Aquaculture Journal doi: 10.3390/aquacj6030035

Authors: Elshafia Ali Hamid Mohammed Gábor Kardos Renáta Bőkényné Tóth Károly Pál

Antimicrobial resistance (AMR) in aquaculture environments has become an increasing concern due to the dissemination of antibiotic-resistant bacteria in aquatic ecosystems. This study investigated the occurrence of presumptive antimicrobial-resistant bacteria in commercial fish farms in Hajdú-Bihar county, Hungary. Between 2023 and 2024, water samples were collected from fishponds from Hajdúszoboszló, Biharugra, and Debrecen, followed by membrane filtration with 0.45 µm pore size mixed cellulose ester membrane filters, bacterial isolation using selective media including vancomycin-resistant enterococci (VRE) agar, Eosin Methylene Blue (EMB) agar, and Endo’s medium. The phenotypic characterization revealed the presence of diverse bacterial populations that could be associated with potential antimicrobial resistance. Bacterial identification using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) showed several bacterial genera, predominantly Acinetobacter, Pseudomonas, Enterococcus, Bacillus, and Escherichia. A total of 16 presumptive antimicrobial-resistant bacterial isolates recovered from selective media were identified using MALDI-TOF MS. Several detected species, including Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus faecium, and Enterococcus faecalis, are recognized as opportunistic bacteria associated with antimicrobial resistance dissemination. The findings demonstrate that aquaculture waters in Hajdú-Bihar county may serve as reservoirs of antimicrobial-resistant bacteria.

Aquaculture Journal doi: 10.3390/aquacj6030034

Authors: Emese Bozánné Békefi István Lénárt Irina Markovina Zsuzsanna Brlás-Molnár Gergő Gyalog Gyula Kasza Dávid Szakos Atilla Kunszabó László Váradi

Laos is one of the 32 landlocked developing countries (LLDCs) of the world, where isolation from the sea and the lack of a large-scale fishing industry have a direct effect on fish supply and fish consumption. Per capita fish consumption in LLDCs amounted to 5.1 kg/year in 2023, which is much lower than the world average (20.3 kg) as well as the Developing Regions average (20.0 kg). However, per capita fish consumption in Laos has reached 28.5 kg/year in 2023, representing the highest among the 32 LLDCs. Relying on the results and experiences of several decades of work in aquaculture development in Laos and taking into account the observations of local and international publications, documents and statistics included, the authors aimed at identifying the principal reasons for the elevated fish consumption in Laos from different perspectives, including that of aquaculture, as well as Lao language, culture, and religion. In this review, the authors analyzed the availability of aquatic resources, the role of fishing and aquaculture in the Lao economy and social life, market realities, as well as the importance of fish in Lao culture.

Aquaculture Journal doi: 10.3390/aquacj6030033

Authors: Maria Vitoria Santos de Almeida Marco Shizuo Owatari Gabriel Fernandes Alves Jesus Adolfo Jatobá

The study evaluated the bioremediation potential of a commercial probiotic composed of multi-strain Bacillus (B. subtilis CCT 0089, B. amyloliquefaciens ATCC 31592, B. licheniformis CCT 7836 and B. megaterium CCT 7935) in biofloc technology (BFT). In vitro, the ideal dosage was identified between concentrations [0.01], [0.10], [1.00], and [10.00] g m−3. Additionally, the growth of probiotic species was characterised in different temperature and oxygen conditions, resistance in 3.0% sodium chloride culture medium, enzyme production (protease, amylase, and lipase) and antibacterial activity. The in vivo experiment evaluated the bioremediation potential of the probiotic and its impact on the growth performance of Nile tilapia Oreochromis niloticus raised in BFT conditions. The group that received the multi-strain Bacillus probiotic at a dosage of 0.10 g m−3 experienced a decrease in floc volume, toxic ammonia, and nitrate levels, leading to environmental enhancements and improved well-being for the cultured organisms. It is advisable to use the multi-strain probiotic at a dosage of 0.10 g m−3 in BFT conditions.

Aquaculture Journal doi: 10.3390/aquacj6030032

Authors: Hyun-Mi Jung Hyun-Jung Kye Sun-Hye Bae Soo-Hwan Kim Su-Kyong Kim Hyun-Chul Kim Seok-Ryel Kim

Acute hepatopancreatic necrosis disease (AHPND) is one of the most devastating bacterial diseases affecting Pacific white shrimp (Litopenaeus vannamei) aquaculture worldwide. Although Vibrio parahaemolyticus has been recognized as the principal causative agent of AHPND, increasing evidence indicates that Vibrio campbellii also plays an important role in disease outbreaks. The present study investigated the pathogenicity and temporal dynamics of pirA transcription in V. campbellii isolated from cultured L. vannamei. The isolate was identified by 16S rRNA sequencing, and pirA expression was quantified during bacterial growth under in vitro conditions and throughout experimental infection in vivo using quantitative real-time PCR. In vitro, pirA transcription increased rapidly during the exponential growth phase and reached its highest level at 6 h after incubation, followed by a gradual decline despite continued bacterial growth. Immersion challenge experiments using juvenile shrimp (1 × 106 CFU/mL) resulted in cumulative mortality exceeding 90% within 48 h post-infection. In vivo, pirA transcription remained relatively low during the early stage of infection but increased markedly at 36 h post-infection, coinciding with rapid mortality and severe hepatopancreatic damage. Histopathological examination revealed progressive epithelial cell sloughing, degeneration of B- and F-cells, tubular collapse, and extensive tissue necrosis, which are characteristic lesions of AHPND. These findings demonstrate that V. campbellii possesses strong pathogenic potential. Temporal induction of pirA transcription was closely associated with severe hepatopancreatic lesions and mortality during experimental infection. Collectively, these findings provide new insights into the temporal dynamics of pirA transcription during AHPND progression and its association with tissue pathology and mortality, supporting the development of early molecular diagnostics, disease surveillance, and biosecurity strategies for sustainable shrimp aquaculture.

Aquaculture Journal doi: 10.3390/aquacj6030031

Authors: Shehu L. Akintola Lateef A. Badmos Akinkunmi S. Ojo Gbenga R. Ajepe Matthew A. Ajibade Mary A. Gbadamosi Victor T. Okomoda Idowu J. Fasakin Sunil Siriwardena Charles Iyangbe Esther W. Magondu Rodrigue Yossa

Error in Institutional Review Board Statement and Informed Consent Statement [...]

Aquaculture Journal doi: 10.3390/aquacj6030030

Authors: Kala-Mallik Meesala Abigeal D. Adeyemi Sarah Janson Jeongwhui Hong Mark P. Polinski Gary Burr Michael Lomas Wendy M. Sealey Deborah A. Bouchard Michael Habte-Tsion

Functional feed ingredients with antimicrobial activities are being explored as a tool to mitigate diseases in Atlantic salmon (Salmo salar L.). Skeletonema marinoi is a marine diatom known to have antimicrobial activity. Here, two separate experiments, including a growth study (Exp. 1) and a bacterial challenge (Exp. 2), were conducted to evaluate the effects of dietary S. marinoi as a functional feed ingredient on the growth, feed utilization, stress biomarkers, antioxidant defense, and immunogenic responses of Atlantic salmon. In Exp. 1, a 16-week growth trial was conducted in a recirculating aquaculture system (RAS) stocked with ten fish (59.6 ± 1.6 g, initial weight) in each of five replicate tanks per treatment. Fish were fed twice daily with either the reference diet or the reference diet supplemented with 0.5% S. marinoi. In Exp. 2, a 27-day bacterial challenge with Vibrio anguillarum Serotype O3 (SO3) was conducted in RAS using 36 fish (100–150 g) per 150 L tank in triplicate. Fish were acclimatized to the RAS for 14 days and fed twice daily with the reference or 0.5% S. marinoi diet prior to the bacterial challenge. Blood plasma, liver, and intestine samples were collected after the growth trial, before (initial, 0 day) and post-challenge (5, 10, 27 days). The results indicated that in Exp. 1, there were no significant differences in survival, final weight, weight gain, feed intake, feed efficiency, condition factor, and hepatosomatic index between fish fed the reference diet and 0.5% S. marinoi diet (p > 0.05). In Exp. 2, before challenge, Atlantic salmon fed the diet with 0.5% S. marinoi showed significantly higher superoxide dismutase (SOD) activity in comparison to fish fed the reference diet. On day 5 post-challenge, significantly higher hepatic malondialdehyde (MDA) was measured in the 0.5% S. marinoi group compared to the reference group. Plasma immunoglobulin M (IgM) level increased (p < 0.05), and intestinal IgM gene expression was up-regulated after challenge in fish fed 0.5% S. marinoi, in contrast to those fed the reference diet at 27 days post-challenge (p < 0.05). Overall, these findings suggest that S. marinoi is more likely to be associated with immune modulation rather than adverse stress response; however, further work is required to confirm pathogen-specific immunity.

Aquaculture Journal doi: 10.3390/aquacj6030029

Authors: Ladan Jahangiri Long Yin Yau Darren Michael Green Margaret Crumlish Spencer Russell Tzu Hsuan Cheng Tanisha Ashley Dias Sophie St-Hilaire

Bacterial stomatitis, or mouth rot (MR), caused by Tenacibaculum maritimum, is a persistent health issue for farmed Atlantic salmon (Salmo salar) in seawater, leading to elevated mortality and reduced growth during the early months of production. Despite its impact, economic estimates of MR have been lacking. We developed a model to estimate selected direct costs associated with MR at the farm and industry levels in British Columbia (BC), Canada. This model incorporated parameters directly affected by MR, including revenue loss from mortality, and antibiotic treatment costs, while accounting for the feed-cost offset associated with mortality. To address variability across farms, MR-associated mortality, non-MR mortality, smolt weight, the number of treatments for MR, fish sale price, feed price, price of drug, and the proportion of farms affected by MR were simulated (Monte Carlo simulation with 10,000 iterations) using ModelRisk. Results indicated that MR imposed an average farm-level economic burden of USD 0.74 million (SD: USD 0.45 million) per production cycle and an industry-level burden of USD 10.58 million (SD: USD 6.54 million) annually. This study provides model-based estimates of selected direct economic costs associated with MR, based on BC specifications, and highlights the need for improved mitigation strategies and policy prioritization for this disease.

Aquaculture Journal doi: 10.3390/aquacj6030028

Authors: Michalis Menicou Marios Charalambides George Triantaphyllidis Stephanos Charalambous Ioannis Kyriakides Rana Abu Alhaija Olympia Nisiforou

This study presents the development and application of an integrated Geographic Information System (GIS)-based Marine Spatial Planning (MSP) framework for identifying suitable offshore aquaculture development zones in Cyprus. The methodology, developed within the OS AQUA project, combines environmental exclusion analysis, weather and proximity assessment, stakeholder and policy evaluation, and carrying-capacity estimation within a unified spatial decision-support framework. A sequential three-phase analytical workflow was applied to progressively refine candidate offshore areas under environmental, operational, infrastructural, regulatory, and governance considerations. The analysis identified four candidate offshore aquaculture zones in Cyprus—Xylofagou West, Larnaka (Faros area), Governor’s Beach, and Aphrodite Hills/Avdimou—demonstrating comparatively favourable conditions for offshore aquaculture development. The results highlight the importance of integrating environmental compatibility, operational feasibility, accessibility, stakeholder acceptance, and sustainability considerations within offshore aquaculture planning processes. Carrying-capacity assessment further indicated substantial offshore production potential under precautionary operational assumptions. Beyond the Cyprus case study, the proposed GIS-MSP framework offers a transferable methodological roadmap for offshore aquaculture zoning, Allocated Zones for Aquaculture (AZA) establishment, and sustainable marine spatial planning in the Mediterranean region.

Aquaculture Journal doi: 10.3390/aquacj6030027

Authors: Tania del Carmen Villalbazo-García Benigno Ortiz-Muñiz María del Refugio Castañeda-Chávez Fabiola Lango-Reynoso Antonio Huerta-Estévez Olaya Pirene Castellanos-Onorio

The contamination of aquaculture products and effluents by Emerging Contaminants (ECs)—originating from both direct chemical applications and peripheral industrial activities—represents a critical global concern due to the environmental and public health risks associated with their persistence, bioaccumulation, and environmental dispersion. This systematic review aimed to synthesize the available scientific evidence on the occurrence, sources, environmental and human health impacts, and mitigation strategies of ECs in aquaculture production systems. A systematic literature search was conducted following the PRISMA 2020 guidelines across the Web of Science, Scopus, and Google Scholar databases. Studies were selected according to predefined eligibility criteria, resulting in a total of 137 studies included in this review. The findings indicate that these pollutants accumulate within the tissues of farmed organisms, posing direct ingestion risks to humans, while contaminated effluents facilitate the widespread degradation of receiving water bodies. Given their environmental persistence and ubiquitous distribution, there is an urgent need for advanced analytical methodologies, robust regulatory frameworks, and the implementation of sustainable treatment technologies—such as advanced oxidation processes and recirculating aquaculture systems—alongside strategies for reducing antibiotics and microplastics. These measures are essential to mitigate the prevalence of ECs and safeguard both ecosystem integrity and human health.

Aquaculture Journal doi: 10.3390/aquacj6030026

Authors: Avishek Bardhan Shivananda H. Murthy Karthik Pulugurtha Haven King-Nobles Camelia Chattopadhyay Debapriyo Mukherjee

Anesthetic agents are widely used in aquaculture to facilitate handling, transport, surgery, vaccination, tagging, and other husbandry procedures. However, most previous reviews have primarily focused on induction time, recovery duration, and welfare outcomes, with comparatively limited emphasis on blood physiology as an indicator of systemic anesthetic safety. The present review synthesizes current evidence regarding hematological, hemato-biochemical, blood gas, and immunohematological alterations induced by major anesthetic classes in aquaculture species. Literature published between 2000 and 2026 was retrieved from Scopus, Web of Science, Google Scholar, PubMed, ScienceDirect, and Springer Nature databases, with approximately 150 studies included following structured screening. Available evidence indicates that anesthetic exposure frequently alters erythrocyte and leukocyte profiles, cortisol secretion, glucose and lactate metabolism, hepatic enzyme activity, electrolyte balance, acid–base regulation, and blood oxygen transport. Respiratory depression, hypercapnia, hypoxemia, and transient metabolic acidosis were recurrent consequences of deep anesthesia, particularly during prolonged exposure or unfavorable environmental conditions. Several anesthetics also modulated innate immune responses through alterations in complement activity, respiratory burst function, cytokine signaling, and leukocyte redistribution. Collectively, the review highlights blood physiology as an essential framework for evaluating anesthetic safety and improving welfare-oriented aquaculture practices.

Aquaculture Journal doi: 10.3390/aquacj6030025

Authors: Aakriti Khanal Khanh Q. Nguyen Cristhian S. Andres Adela N. Araujo Trenton L. Corby Melanie Rhodes Timothy J. Bruce D. Allen Davis

Two growth trials were conducted to evaluate the effects of solvent-extracted soybean meal (SBM), low-oligosaccharide soybean meal (LO-SBM), and enzyme-treated soybean meal (ET-SBM) on the growth performance, feed utilization, and gut microbiome of the Pacific white shrimp (Litopenaeus vannamei). Nine diets were tested, including a basal diet using solvent-extracted soybean meal as the main protein source. The solvent-extracted soybean meal was then replaced with LO-SBM or ET-SBM at 40%, 60%, 80%, and 100% on an isonitrogenous and isolipidic basis. In the 8-week outdoor green water trial, all growth metrics, FCR and apparent net protein retention (ANPR) showed no significant differences among diets (p > 0.05). However, there was a significant effect of LO-SBM on phosphorus retention. In the clear water trial, intermediate inclusion levels of LO-SBM (60–80%) slightly improved growth metrics and phosphorus retention (p < 0.05) without affecting protein utilization, while 100% LO-SBM did not provide additional benefits. Diets with ET-SBM showed similar performance; however, phosphorus retention was reduced. Diets did not affect whole-body composition (p > 0.05), except for phosphorus and moisture. Gut microbiota analysis revealed that shrimp fed 100% ET-SBM had notably higher alpha diversity (Shannon index = 5.45, observed species = 326.41) compared to those fed 100% LO-SBM (Shannon index = 4.59, observed species = 242.69), indicating improved microbial stability with ET-SBM. Nonetheless, there were no significant differences in beta diversity or taxonomic composition between treatments (p > 0.05). This study demonstrates that incorporating 60–80% LO-SBM into the diet improves shrimp growth and nutrient utilization. Additionally, ET-SBM may also support shrimp growth, nutrient efficiency, and microbial diversity, suggesting that both LO-SBM and ET-SBM can be beneficial for shrimp nutrition.

Aquaculture Journal doi: 10.3390/aquacj6030024

Authors: Shozo H. Sugiura

Digestibility is a fundamental concept in animal nutrition and is widely used to evaluate feed ingredients. Although digestibility values are generally expected to be positive, negative values are occasionally reported. Negative values are not analytical or calculation errors; rather, they often convey critical information about feed ingredients. Negative digestibility is most commonly observed for minerals, which readily interact with other components in compound feeds and within the gut lumen. A proper understanding of negative digestibility is therefore essential for formulating nutritionally complete diets. This paper introduces Mellanby’s toxamin theory to illustrate the mechanisms underlying negative digestibility. It also explains the rationale behind digestibility calculations, which sometimes yield mathematically extreme and biologically unrealistic negative values. Finally, the paper proposes in vivo mineral-binding capacity as an alternative metric for expressing ingredient interactions, as negative digestibility values themselves can lead to confusion and misinterpretation. By reinterpreting the biological significance of negative digestibility, this paper seeks to translate an often-confusing observation into a more practical and informative nutritional index.

Aquaculture Journal doi: 10.3390/aquacj6030023

Authors: Carlos A. Mendez María Cristina Morales German E. Merino

In this study, total ammonia nitrogen (TAN) excretion rates were quantified in juvenile (mean weight: 1.79 ± 0.17 g) and adult (mean weight: 15.91 ± 0.63 g) prawns (Macrobrachium caementarius) reared under recirculating aquaculture system (RAS) conditions representative of small-scale farming operations. Prawns were fed a commercial dry pelleted diet (48.5% crude protein) at a daily ration equivalent to 5% of total biomass. Water quality parameters were maintained within species-specific tolerance ranges to ensure normal physiological and metabolic function. TAN excretion rates were estimated using a mass balance approach under closed-flow batch conditions. A significant difference in TAN excretion was observed between life stages (p = 0.008): juveniles excreted 0.009 ± 0.006 mg TAN g−1 h−1 (0.22 ± 0.18 mg TAN g−1 day−1), whereas adults excreted 0.03 ± 0.01 mg TAN g−1 h−1 (0.73 ± 0.06 mg TAN g−1 day−1). Distinct diel postprandial patterns were evident in both life stages, with peak TAN release occurring 1–2 h after each feeding event, followed by a gradual decline. These life-stage differences have direct implications for RAS design and biofilter management and should be interpreted in the context of the dietary conditions used. The quantified excretion rates provide baseline bioengineering parameters for sizing biofilters, estimating nitrogen loading, and optimizing water quality management for this emerging aquaculture species.

Aquaculture Journal doi: 10.3390/aquacj6030022

Authors: David Johane Machate Queenta Ngum Nji Patrick Berka Njobeh

This study evaluated trace element bioaccumulation in Nile tilapia (Oreochromis niloticus) marketed in Brazil and assessed potential implications for food safety and human health. A total of 120 farmed fish samples, including whole fish and tissues (gills, kidneys, liver, and muscle), were analyzed. Concentrations of Al, As, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and compared with ANVISA and FAO/WHO guideline values. Arsenic concentrations complied with ANVISA limits, whereas Pb in whole Nile tilapia exceeded the permissible threshold. Nickel and Se concentrations in muscle and whole fish also surpassed FAO/WHO guidelines. Estimated Se intake from consumption of whole tilapia and muscle (fillet) reached 188.01% of the Recommended Dietary Allowance (RDA) for children aged 8 years. Contamination index values (CI) indicated bioaccumulation of Ni in multiple tissues and Se in edible portions. Human health risk assessment identified carcinogenic risks associated with As, Cr, Ni, and Pb, while non-carcinogenic risk (HI > 1) was primarily driven by As exposure. These findings highlight the need for continuous monitoring of trace elements in aquaculture products.

Aquaculture Journal doi: 10.3390/aquacj6020021

Authors: Zipporah M. Gichana Bonface O. Manono Eric O. Omwenga Kobingi Nyakeya

Global food production systems are increasingly challenged by population growth, climate change, water scarcity, and environmental degradation, necessitating the adoption of sustainable, resource-efficient food production strategies. Aquaponic systems integrate recirculating aquaculture with hydroponic crop cultivation, enabling nutrient recycling and improved water-use efficiency. Simultaneously, CRISPR/Cas9 genome-editing technology has emerged as a powerful tool for precise genetic improvement of economically important aquaculture traits. This review critically evaluates current progress in CRISPR/Cas9 applications in aquaculture, with emphasis on Nile tilapia (Oreochromis niloticus). Evidence from peer-reviewed studies indicates that targeted modification of genes associated with growth regulation, disease resistance, nutrient metabolism, feed efficiency, and stress tolerance can significantly enhance fish productivity and physiological resilience. Genes involved in hypoxia adaptation and nitrogen metabolism may further improve environmental performance in intensive recirculating systems by reducing ammonia accumulation and enhancing nutrient utilization. However, most genome-editing studies have been conducted under laboratory or conventional aquaculture conditions, with limited information available regarding the long-term performance, ecological interactions, microbial dynamics, and biosafety of genome-edited fish in aquaponic environments. Technical limitations including off-target effects, mosaicism, delivery efficiency, regulatory uncertainty, and public acceptance continue to constrain large-scale implementation. In the short term, CRISPR/Cas9 applications are likely to focus on practical trait enhancement under controlled aquaculture systems, whereas longer-term research may explore fish lines specifically optimized for nutrient cycling, environmental resilience, and integrated aquaponic sustainability. Overall, CRISPR/Cas9-mediated genome editing represents a promising but still emerging strategy for improving sustainable aquaculture and aquaponic food production systems.

Aquaculture Journal doi: 10.3390/aquacj6020020

Authors: Pedro Martínez Noguera Raju Podduturi Mikael A. Petersen Niels O. G. Jørgensen

The impact of a commercial microbial population (product name “RAS Right”) on the off-flavours geosmin and 2-methylisoborneol (2-MIB) in water and fish of a recirculating aquaculture system (RAS) for Nile tilapia production was studied over five months. The “RAS Right” product contains a microbiome that is reported to reduce geosmin. In the system that received “RAS Right”, geosmin ranged from 1.6 to 171.2 ng/L, while 2.4 to 89.3 ng/L occurred in the control RAS. After fluctuations in the first two months, water in the control RAS had lower geosmin concentrations (mean of 8.8 ng/L) than the treated RAS (mean of 16.6 ng/L). 2-MIB was low (<4.3 ng/L) or undetectable in both the control and treated systems. In the fish, geosmin varied from 112 to 3683 ng/kg, with the highest levels measured in the treated RAS during three of eight samplings. 2-MIB in the fish ranged from 11.6 to 136 ng/kg and peaked in the treated RAS in one sampling. The results indicate that “RAS Right” did not produce a significant reduction of geosmin or 2-MIB in water or fish. However, optimisation of the treatment with respect to dose or addition frequency may improve its effect, though this remains to be examined.

Aquaculture Journal doi: 10.3390/aquacj6020019

Authors: Eleanor Makin Georgina Shilton Olivia Brotherhood Amaara Rassool-Amin Kyle Gordon Harini Satkunarasa Paula Reynolds Ian Wellby Jessica Locker Omar Qutachi Chris Young

Opportunistic bacterial and fungal infections from surface wounds remain a persistent threat to aquaculture, resulting in significant economic losses and reduced stock welfare. Topical wound sealants are widely employed in recreational aquaculture applications, yet no market regulation or efficacy data exist to support their usage. The broader biological/environmental impacts of these products also remain poorly characterized. This study provides the first quantitative assessment of the antibacterial, antifungal and cellular toxicity of a panel of commercially available topical ‘carp care’ formulations. Our data highlights highly variable to no functional growth inhibition or killing of microbial pathogens, significant inherent cyprinid cellular toxicity, and lack of submerged wet adhesion in all products tested. We show for the first time that commercial propolis solutions are ineffective against the four main pathogenic microorganisms affecting carp. Propolis formulations were also found to induce apoptosis and ROS generation in cyprinid cells in vitro, and permeabilise intact carp skin, questioning the foundation of propolis formulations in topical wound-care treatments for carp rearing/angling. We show improved efficacies can be attained through natural compound implementation, with increased antibacterial and antifungal effects, inherent regenerative benefits to cyprinid fibroblasts, and improved human and environmental safety profiles. This research demonstrates the widespread lack of efficacy in currently commercially available wound sealants for carp; of those tested here, many popular formulations are in fact inherently toxic to carp cells, and also have a permeabilizing effect on intact carp skin due to carrier solvent effects, providing a route for secondary infection; most show no activity against any common carp pathogens; and all uniformly lacked wet adhesion. This work provides a framework standard for the future development of topical wound-care formulations for carp and highlights the need for better dialogue between trade and academia when designing novel wound-care products.

Aquaculture Journal doi: 10.3390/aquacj6020018

Authors: Shehu L. Akintola Lateef A. Badmos Akinkunmi S. Ojo Gbenga R. Ajepe Matthew A. Ajibade Mary A. Gbadamosi Victor T. Okomoda Idowu J. Fasakin Sunil Siriwardena Charles Iyangbe Esther W. Magondu Rodrigue Yossa

This field study examined extant aquatic food production and marketing in the three coastal states of Lagos, Ogun, and Ondo before IMTA across 15 Local Government Areas (LGAs)/Local Council Development Areas (LCDAs). Marketing mix practices in coastal aquatic food systems were explored through a structured, qualitative assessment using a multi-value chain perspective. Monthly sales volumes most frequently fell within the range of 1–5 tonnes. The local market was dominant, with some sales in the international markets. Respondents asserted that post-harvest processing was diverse, and some were satisfied with the technology available to preserve their products. Cold storage practices across coastal states were hindered by unreliable power supply. Zero-level channel distribution dominated among traders, with over 90% relying on word-of-mouth (WOM) to promote their products. Consumers showed a strong preference for the quality of local products and expressed openness to incorporating seaweed into their purchases. Health benefits, taste, and other reasons for purchase decisions varied significantly across the state χ2 (df = 8, n = 300) = 92.39, p < 0.001. These findings provide a baseline for IMTA in Nigeria, highlighting existing strengths, market dynamics, and infrastructure gaps that must be addressed to support sustainable integration.

Aquaculture Journal doi: 10.3390/aquacj6020017

Authors: Nguyen Thanh Vu Kathiresan Purushothaman Maria G. Nayfa Nga Thi Thanh Vu Bing Liang Joyce Koh Hin Hung Tsang Sk. Ahmad Al Nahid Grace Loo Xueyan Shen Jose A. Domingos Dean R. Jerry Shubha Vij

Malabar red snapper (Lutjanus malabaricus) is widely farmed across Asia (e.g., China, Malaysia, Singapore, Taiwan) and is highly valued in regional markets. Despite its importance to fisheries and aquaculture, population structure and genetic connectivity between wild and farmed populations across the South China Sea remain poorly understood. We analyzed 594 individuals retained after quality filtering from an initial dataset of 930 samples, representing eight wild and farmed populations spanning north-eastern Australia (Queensland) and the South China Sea region (Hong Kong, Malaysia, Singapore, Taiwan), using 18,177 SNPs to quantify genetic diversity, population structure, and effective population size (Ne). Genetic differentiation was low but significant. Wild populations from Australia were differentiated from all other populations, indicating regional genetic isolation. In contrast, farmed populations from Malaysia and Singapore clustered closely with wild populations from Hong Kong and Singapore, indicating regional connectivity. Effective population size (Ne) in farmed populations was low (Ne = 49.1–138.6). Farmed populations from Malaysia and Singapore formed a genetically connected cluster, whereas the Taiwan farm population was genetically distinct. Low Ne was observed in farmed populations from Singapore and Taiwan. These findings support aquaculture management by identifying Australian populations as a distinct unit and enabling biosecure broodstock exchange within the Malaysia–Singapore cluster to minimize inbreeding and strengthen sustainable selective breeding programs.

Aquaculture Journal doi: 10.3390/aquacj6020016

Authors: Per Harald Rødvei Knut Ingar Westeren Eva Brod Jon Meisfjord

Smolt production in freshwater is an essential component of the salmonid aquaculture production chain. But it generates sludge (feed waste and fish feces) that must be managed to meet environmental regulations. While sludge can be reused as a resource, there are limited empirical results about cost structures, market conditions, and energy implications in industrial aquaculture. This study analyzes sludge collection, processing, and utilization based on a single-case study of a Norwegian smolt producer (Sisomar AS). The analysis combines company-level production data, accounting information, and process descriptions. In 2023, the company produced approximately 9.2 million smolt (1184 tons of biomass), generating 140 tons of dried sludge. Sisomar’s value creation from production of bio-based fertilizer from sludge is relatively close to that of comparable mineral fertilizers, but a direct comparison here is difficult because of large variations in the prices of mineral fertilizers. The energy consumption is significantly lower for organic fertilizer from Sisomar compared to standard technology for mineral fertilizer production. Bio-based fertilizers are looked at as an important contribution to dealing with environmental challenges, and this study discusses the characteristics of how market structures have importance for this.

Aquaculture Journal doi: 10.3390/aquacj6020015

Authors: Tiruken Aziz Atnafu Anisa Mitra Folasade Damilola Amulejoye Missinhoun Dagoudo Chikumbutso Memory Phiri Amoah Kwaku Lee Seong Wei Sahya Maulu

Aquaculture is expanding rapidly, creating a greater need for sustainable and cost-effective feed ingredients to reduce reliance on traditional protein sources such as fishmeal (FM) and soybean meal (SBM). Insect-derived frass, which consists of insect excrement, molted exoskeletons, uneaten substrate, plus associated microbial biomass, has shown potential as a viable and sustainable ingredient in aquafeed. Although traditionally used as an organic fertilizer, its richness in essential nutrients and bioactive compounds highlights its potential as a partial substitute for conventional feedstuffs. This study synthesizes current research on insect-derived frass, focusing on its nutritional composition and effects on growth performance, immunity, health, and gut microbiota in aquaculture species, alongside environmental, economic, safety, and regulatory considerations. Although a wide range of insect species have been evaluated for use in aquafeeds, research on insect frass has primarily focused on black soldier fly and yellow mealworm, with most studies examining its application in omnivorous fish species. Despite its promise as a circular economy-aligned aquafeed ingredient, challenges remain due to nutritional and amino acid variability, largely influenced by the quality of the original insect rearing substrate, as well as species-specific responses and potential contamination risks. To promote widespread adoption of insect-derived frass in aquafeed, there is a need to optimize insect rearing substrate selection and processing, define inclusion levels by insect and target aquatic species, establish safety protocols, and develop harmonized international standards.

Aquaculture Journal doi: 10.3390/aquacj6020014

Authors: Felipe de Jesús Reynaga-Franco José Pablo Vega-Camarena Jaime Edzael Mendivil-Mendoza Alejandro García-Ramírez Martina Hilda Gracia-Valenzuela Jorge Chávez-Villalba

The discharge of effluents from shrimp farms into coastal lagoons can alter food availability, water quality, and pollutant load, potentially affecting the biological performance and safety of farmed bivalves. This study evaluated the influence of shrimp farm effluents on the growth, total weight, and condition index of the Pacific oyster Crassostrea (Magallana) gigas. Two oyster cultivation zones were established in the coastal lagoon of Los Melagos (Sonora, Mexico): one near a shrimp effluent zone (EZ) and the other in a reference effluent-free zone (FZ). Shell height and length, total weight, and condition index were measured monthly, along with environmental variables, including chlorophyll “a” concentration and sea surface temperature obtained from satellite imagery. Oysters cultivated in EZ showed significantly higher total weight, condition index, and growth rates compared to those in FZ. Seasonal fluctuations in chlorophyll “a” were observed, reflected in growth patterns, suggesting greater food availability in waters influenced by effluents. However, these environments pose health risks that require continuous, integrated environmental and health monitoring.

Aquaculture Journal doi: 10.3390/aquacj6020013

Authors: Mohammad Abu Baker Siddique Ilias Ahmed Balaram Mahalder Mohammad Mahfujul Haque Mariom A. K. Shakur Ahammad

This study applied time-series modeling using autoregressive integrated moving average (ARIMA) to compare the growth performance of tilapia broodfish in pond and recirculating aquaculture systems (RAS) from June 2023 to May 2024. Descriptive statistics showed a higher mean percentage weight gain under RAS (26.69%) than pond culture (23.75%), although monthly variability in the RAS dataset was influenced by an outlier, which may be attributed to influential exogenous factors rather than water-quality parameters. Normality, stationarity, and autocorrelation diagnostics confirmed that both datasets were appropriate for ARIMA modeling without differencing. Multiple ARIMA models were evaluated based on RMSE, MAPE, MAE, AIC, BIC, and residual behavior; ARIMA (1,0,1) emerged as the best fit for both systems. Forecasting up to May 2028 revealed stable long-term growth patterns, with RAS consistently showing slightly higher forecasted growth compared to pond culture, although the difference remained small in absolute terms. Predictions remained within model-generated 95% confidence intervals; however, these results indicate internal model consistency rather than independent validation of predictive accuracy. The findings highlight that RAS offers more consistent and slightly superior growth performance, supporting its potential for optimized broodfish production. Recommendations emphasize adopting RAS for enhanced growth predictability and improved management in tilapia aquaculture.

Aquaculture Journal doi: 10.3390/aquacj6020012

Authors: Lorenzo Zanella Giulio Rova Marco Morin Matteo Martellato Emanuele Rossetti Renato Palazzi

Pre-fattening (also referred to as nursery culture) of Manila clam is a priority for this sector of aquaculture, as it allows hatchery-produced seed (1–3 mg) to reach sowable juvenile sizes of 30–100 mg and reduces reliance on natural juvenile recruitment. This study evaluated the efficiency of two early pre-fattening systems, both in economic terms and in product quality: conventional upwelling units (a high-density system) and flat-bottom tanks (a mid-density system), the latter tested with and without a sand layer. The 51-day trial was conducted under autumn environmental conditions (temperature 13–25.8 °C; salinity 25–28 ppt; chlorophyll-a 3–24 µg/L), starting with 1.34 mg seed maintained under a water flow rate ≥ 15–20 mL/min/g. In upwelling units, the initial density was ~216 ind./cm2. Four grading events produced four size classes, with total mean weights ranging from 6.4 mg in the smallest (tails) to 46.3 mg in the largest (heads). The overall population mean size was 19.0 mg, with a specific growth rate (SGR) of 5.2%/day and mortality of 17.6%. Flat-bottom tanks, stocked at ~30 ind./cm2, achieved higher growth (overall weighted mean: 28.0 mg; SGR ~6%/day), but exhibited higher mortality (26.0% on average), with no significant effect from the presence of bottom sand. Overall, flat-bottom systems showed promising growth performance with reduced labor requirements, suggesting that this system could represent a viable alternative to upwelling. However, the associated rearing protocol could still be improved by optimizing stocking density and water exchange rates.

Aquaculture Journal doi: 10.3390/aquacj6020011

Authors: Serge Dossou Matthew Alun Griffiths Owen Rodrigue Yossa

Sustainable aquaculture growth necessitates innovative strategies to meet the global protein demand while minimizing environmental impacts. This narrative review synthesizes the current understanding and emerging approaches for optimizing nutrient cycling and trophic transfer efficiency in pond-based aquaculture systems. We highlight two primary strategies: ‘demand-oriented feeding’, which adaptively balances feed inputs with natural food availability, and the ‘nutritious pond concept’, which enhances pond ecology through carbon/nitrogen ratio management and waste-driven nutrient recycling. A critical examination of the scalability and environmental trade-offs associated with these strategies is also presented. Despite the challenges presented by these strategies, their combination could create a more dynamic, ecosystem-based approach to aquaculture that is more resource-efficient and environmentally friendly, contributing to the development of ponds as sustainable, productive ecosystems that enhance efficiency, reduce waste, and support economic viability. Finally, we explored polyculture as an ecological strategy, highlighting its synergistic mechanisms for maximizing food web efficiency and its potential to enhance the two primary strategies.

Aquaculture Journal doi: 10.3390/aquacj6010010

Authors: Christina Zantioti Emmanouil E. Malandrakis

Skin pigmentation is a crucial factor influencing the market value of gilthead seabream. A three-month feeding trial evaluated the effects of dietary inclusion of Rhodotorula mucilaginosa on skin and fillet pigmentation of gilthead seabream (Sparus aurata). Four diets containing yeast were tested in triplicate tanks using 120 fish in total. Skin and fillet colours were assessed via computer-based image analysis in CIELAB, RGB and HSB spaces. Analysis of total carotenoids was also performed. Yeast inclusion increased L* and Whiteness values in the operculum and enhanced lightness in ventral skin regions. In the abdominal area, RGB values decreased, particularly in the 3% diet. Fillet responses were limited to the red muscle, where the 3% diet significantly increased a* and Chroma values. Overall, inclusion of R. mucilaginosa exceeding 2% influenced seabream skin brightness and total carotenoid content, while 3% inclusion enhanced red muscle pigmentation, suggesting potential as a natural pigment source in seabream feeds.

Aquaculture Journal doi: 10.3390/aquacj6010009

Authors: Etienne J. de Jongh Kelsey Robertson Jacob A. Narbonne F. Carl Uhland Richard J. Reid-Smith Simon J. G. Otto

The objective of this study was to evaluate relationships between antimicrobial use (AMU) and antimicrobial resistance (AMR) in isolates from farmed Atlantic salmon that could represent finfish pathogens in the British Columbia (BC) aquaculture industry using historical surveillance data. Antimicrobial susceptibility data were obtained for 1040 bacterial isolates from farmed Atlantic salmon submissions to the BC Animal Health Centre for 2007–2018. Antimicrobial use data were provided by the BC Ministry of Agriculture and Food from feed mill prescriptions for BC farmed Atlantic salmon for 2007–2018. Multivariable logistic regression models for all bacterial isolates with a random intercept for species were developed to determine associations with outcomes of resistance to trimethoprim-sulfadiazine (SXT), oxytetracycline (OXY), and florfenicol (FLOR). Resistance to SXT, FLOR, and/or OXY were all significantly associated with each resistance outcome in their respective models. Only the SXT resistance model was significantly associated with AMU, specifically potentiated sulfonamide use, but use was not significantly associated with AMR for any other resistance outcome. The results of this study contribute to the rapidly growing and increasingly pertinent body of literature on AMU and AMR in the unique marine aquaculture environment. Future research at the farm level linking pen-specific AMU to AMR outcomes will provide more understanding of selection pressure for AMR at the local level and provide more guidance for antimicrobial stewardship in finfish aquaculture.

Aquaculture Journal doi: 10.3390/aquacj6010008

Authors: Marissa Breitenstein Elisabeth Bautista Alexis Daniels Andrea Hicks

With the global population projected to continue to increase, the necessity for food security (i.e., a region’s ability to reliably provide food to its residents) becomes ever-present. Aquaculture is currently one of the most prevalent methods for propagating aquatic species, though aquaponics (i.e., combining aquaculture and hydroponics to artificially propagate aquatic species and plants) is often considered a more sustainable food production method in comparison. Though aquaponics is promising both environmentally and socially, the general aquaponics business model is failing to generate proper revenue in many instances. The addition of value-added and value-recovered processes is one option for producers to increase the value of their final products without major capital investment. A paper survey was deployed for this study for both aquaculture and aquaponics operations, given the current prevalence of aquaculture and infancy of aquaponics in the United States. The survey aims to understand the basic parameters of their operation while also gauging interest in the addition of value-added and value-recovered products for their operations. Less than half of the respondents were interested in value-added and value-recovered products for several different reasons. The survey also provides useful information related to operation, prior experiences, and potential future directions for aquaponics in the United States, though investigation into consumer preferences is required for optimized success of the aquaponics industry.

Aquaculture Journal doi: 10.3390/aquacj6010007

Authors: Calixto Quispe-Pilco Inês Ferreira Diogo Oliveira Rui Resende-Pinto André Gomes dos Santos Freddy Walter Delgado-Cabrera Khiara Aliyah Bet Moreno-Salazar-Calderon Cintia P. Fernández-Cárdenas Fredy Esfrayn Tapia-Alave L. Filipe C. Castro Manuel Nande

Background: The reproductive cycle of Octopus mimus is regulated by environmental and hormonal factors, with photoperiod playing a key role in spawning induction and reproductive maturation. Understanding its underlying molecular mechanisms is essential for developing strategies to enhance controlled reproduction in aquaculture. Methods: We analyzed the expression of genes involved in the photoperiod-activated spawning induction cascade in the optic lobe and its downstream effects on the oviducal gland by performing transcriptomic analyses on females exposed to continuous light (24:0), which inhibits reproductive development, and a natural photoperiod, which induces spawning. The mRNA sequencing (RNA-Seq), quality control, gene annotation, and differential expression analyses were conducted using edgeR. Results: Spawning was completely inhibited under constant light, while 80% of control females spawned. Expression profiling revealed 89 downregulated and 34 upregulated genes in the optic lobe, and 178 downregulated and 237 upregulated genes in the oviducal gland (FDR < 0.05, |log2FC| ≥ 2), including key orthologs such as FMRFamide and myomodulin. Conclusions: These results show that the optic lobe integrates photoperiodic cues that modulate reproductive activation via a neuroendocrine cascade and coordinates spawning regulation through the oviducal gland, providing insights for improving reproductive control in aquaculture systems.

Aquaculture Journal doi: 10.3390/aquacj6010006

Authors: Wilson Wasielesky Lucélia Borges Kiefer Menestrino Mariana Holanda Geraldo Fóes Luís Poersch Dariano Krummenauer

The biofloc technology (BFT) system is widely used in aquaculture for the cultivation of Pacific white shrimp (Penaeus vannamei). While the practice of reusing percentages of water from previous crops to initiate the system is common, this study aimed to determine the minimum inoculum of total suspended solids (TSS) required for the rapid stabilization of nitrogen compounds and the bacterial community. The experiment was conducted in 400 L experimental units stocked with juvenile P. vannamei. We compared six treatments with different initial inoculum concentrations: control (0 mg/L), 2.5 mg/L, 5 mg/L, 10 mg/L, 20 mg/L, and 40 mg/L. These concentrations corresponded to inoculations of 0%, 0.625%, 1.25%, 2.5%, 5%, and 10% of mature biofloc water with an initial TSS concentration of 400 mg/L. Treatments with an inoculum showed a more effective oxidation of ammonia and nitrite compared to the control. However, the 2.5 mg/L treatment differed significantly (p < 0.05) from the other inoculated treatments, exhibiting persistently high ammonia concentrations and a slower stabilization time. Survival rates in the 5, 10, 20, and 40 mg/L treatments were significantly higher (p < 0.05) than in the control and 2.5 mg/L treatments, remaining around 95%, while the latter had survival rates of 48.75% and 65.83%, respectively. The final biomass were as follows: control: 479.7 ± 30 g; 2.5 mg 628.1 ± 93.3 g; 5 mg 976.5 ± 128.1 g; 10 mg 850.3 ± 158.1 g; 20 mg 789.6 ± 122.7 g; 40 mg 856 ± 96.9 g. Final biomass and productivity were highest in the 5 mg/L treatment and did not differ significantly among the 10, 20, and 40 mg/L treatments. The results suggest that in a BFT system for P. vannamei, a minimum inoculum of 5 mg/L of TSS is sufficient to achieve high water quality and superior zootechnical performance.

Aquaculture Journal doi: 10.3390/aquacj6010005

Authors: Eirini Schoina Christine Delbarre-Ladrat Laetitia Kolypczuk Françoise Leroi Delphine Passerini George-John Nychas

Tenacibaculosis is a major bacterial disease in aquaculture, with Tenacibaculum discolor being characterized as one of the causative agents. This study evaluated the antimicrobial and antibiofilm potential of three isolated Pseudoalteromonas strains—Pseudoalteromonas sp. GY795-2 (deep-sea), Pseudoalteromonas spongiae MB2 (aquaculture installation), and Pseudoalteromonas tetraodonis SAE 20 (kelps)—against T. discolor strain FMCC B487. Cell-free supernatants (SNs) from each Pseudoalteromonas culture were tested in microtiter assays, assessing planktonic growth measured by OD600 and biofilm biomass quantified by crystal violet (CV) staining. The addition of the Pseudoalteromonas SNs affected both growth and biofilm development of T. discolor strain FMCC B487. A significant decrease in T. discolor strain FMCC B487 growth and biofilm was observed in the presence of P. spongiae MB2 SN, whereas the SN of Pseudoalteromonas sp. GY795-2 promoted both growth and biofilm development of T. discolor strain FMCC B487. To assess whole-cell activity, dual-species biofilms were formed on plastic surfaces. After 24 h, all three Pseudoalteromonas strains reduced the viable T. discolor strain FMCC B487 population while maintaining their own cell numbers comparable to single-culture controls, suggesting an inhibitory interaction. These results demonstrate that these Pseudoalteromonas strains’ metabolites and cells can modulate T. discolor growth and biofilm development, highlighting their potential as biocontrol agents in aquaculture.

Aquaculture Journal doi: 10.3390/aquacj6010004

Authors: Etienne J. de Jongh Kelsey Robertson F. Carl Uhland Richard J. Reid-Smith Kazal Ghosh Simon J. G. Otto

Antimicrobial use (AMU) in finfish aquaculture production raises concerns about the link between AMU and the development of antimicrobial resistance (AMR) in bacteria found in aquatic organisms and potential transmission to humans and the environment. The objective of this study was to describe the antimicrobial susceptibilities of a historical collection of bacterial isolates from diagnostic submissions from farmed finfish in British Columbia (BC), Canada. Antimicrobial susceptibility data were obtained from the BC Ministry of Agriculture via submissions to the Animal Health Centre for 2007 to 2018 for florfenicol (FLOR), oxytetracycline (OXY), trimethoprim-sulfadiazine (SXT), and triple-sulfa compound (TRI). There were 1237 unique isolates from all finfish species (68 unique bacterial species), of which 1042 were from Atlantic salmon. For all fish species, the most common bacterial species isolated were Aeromonas salmonicida (n = 174), Aliivibrio wodanis (n = 84), and Yersinia ruckeri (n = 79). Resistance was detected to most antimicrobials tested, but levels were generally low. Resistance to FLOR was only detected in A. salmonicida. Low annual isolate numbers precluded genera-specific annual comparisons for all pathogens. Multi-drug resistance was detected, but at low levels. These results provide an important baseline for antimicrobial susceptibility data from bacterial isolates that may cause disease in finfish aquaculture in BC, Canada that will support future Canadian AMR surveillance in farmed aquaculture.

Aquaculture Journal doi: 10.3390/aquacj6010003

Authors: Guoxiang Huang Kunlapat Thongkaew Supapan Chaiprapat

Aquatic animal products are vital to global food security and nutrition, necessitating accurate, scalable, and non-destructive methods for quality assessment in aquaculture. Conventional techniques such as dissection and biochemical analysis are invasive, labor-intensive, and unsuitable for real-time or high-throughput decision-making. This review synthesizes six major categories of non-destructive technologies—electrical, spectroscopic, natural sensory, acoustic, radiographic, and infrared and microwave—classified by their underlying sensing mechanisms and therefore differing measurement capabilities and deployment feasibilities. To support objective technology selection, an Analytic Hierarchy Process (AHP) framework was developed using general performance criteria (cost, accuracy, speed, usability) and one decision-critical application-specific criterion (non-invasiveness), and was demonstrated for ovarian maturation staging in mud crabs by ranking 19 candidate techniques. Accuracy had the highest weight (0.416), but non-invasiveness (0.224) and usability (0.197) substantially influenced the final ranking, illustrating how operational and welfare constraints could shift preferred solutions despite differences in analytical accuracy. Based on the global priority weights (GA), computer vision (CV) was identified as the most suitable option (GA = 0.076), balancing affordability, throughput, ease of deployment, and animal welfare compatibility, whereas high-end modalities such as nuclear magnetic resonance (NMR; GA = 0.073) and computed tomography (CT; GA = 0.070) were constrained by cost and operational complexity. Overall, this review–AHP–case study pipeline provides a transparent and reproducible decision-support basis for selecting non-destructive technologies across aquaculture species and quality targets.

Aquaculture Journal doi: 10.3390/aquacj6010002

Authors: Rafael Angelakopoulos Alexia E. Fytsili Arkadios Dimitroglou Leonidas Papaharisis Katerina A. Moutou

Fish is highly prone to spoilage due to a combination of intrinsic biochemical processes and microbial proliferation, which together drive rapid quality deterioration during post-harvest handling and storage. These processes are further accelerated by factors such as elevated temperatures, mechanical damage, and suboptimal handling. In Mediterranean aquaculture, ice slurry is the standard harvesting method. This study aimed to characterize the initial post-harvest enzymatic activity of key proteolytic enzymes, calpain, collagenase, cathepsin B (CTSB), and cathepsin L (CTSL), in the white muscle of three commercially important species (Sparus aurata, Dicentrarchus labrax, and Pagrus major) harvested under standard practices across three seawater harvest temperatures (low, medium, and high). Muscle samples were collected over a 13-day chilled storage period post-harvest, and enzymatic activity was assessed using standardized fluorometric assays. Our findings establish the basal post-mortem proteolytic profiles for each species and reveal marked species-specific differences in enzyme activity patterns. Calpain and collagenase exhibited early and parallel activation, while CTSB and CTSL showed a coordinated increase during storage. Harvest temperature emerged as a critical factor, with the highest enzymatic activities consistently observed during the moderate temperature period. These results underscore the importance of species-specific physiology and seasonal conditions in shaping post-harvest filet degradation, offering a basis for refining harvest strategies to enhance quality management in Mediterranean aquaculture.

Aquaculture Journal doi: 10.3390/aquacj6010001

Authors: Aylin Trujillo-Rogel Iván Gallego-Alarcón Boris Miguel López-Rebollar David García-Mondragón Iván Cervantes-Zepeda Ricardo Arévalo-Mejía Jesús Ramiro Félix-Félix

Inefficient management of dissolved oxygen (DO) in intensive aquaculture systems limits fish welfare and productivity by creating oxygen-deficient zones and promoting hydrodynamic conditions that hinder their dispersion. Because water movement directly influences how oxygen is transported and mixed within the culture unit, inadequate flow management can allow localized hypoxia to persist even when total oxygen input appears sufficient. To address this issue, this study proposes an integrated methodology that combines in situ respirometry measurements with Computational Fluid Dynamics (CFD) simulations to evaluate the spatial distribution of DO and diagnose the operational performance of aquaculture systems. The methodology quantifies oxygen consumption using intermittent-flow respirometry, applies a three-dimensional two-phase CFD model (water–oxygen) incorporating experimental oxygen consumption rates as boundary conditions, and validates the model under real operating conditions, focusing on active metabolism as the most demanding physiological state. The model generates a spatial distribution of DO patterns that are significantly modified by pond geometry, water flow characteristics, the metabolism of the fish and fish positioning. The differences between experimental and simulated values ranged from 7.8% to 10.7%, confirming the accuracy of the proposed method. The integration of in situ metabolic measurements with CFD modeling provides a realistic representation of DO dynamics, enabling system optimization and promoting more efficient and sustainable aquaculture.

Aquaculture Journal doi: 10.3390/aquacj5040028

Authors: Jasmine V. Rajai Mukesh Baraiya Bhavik Kantilal Bhagiya Jigar A. Sutariya Payal A. Bodar Mujeer Habsi Digvijay Singh Yadav Ramalingam Dineshkumar Harshad Brahmbhatt Santlal Jaiswar Rajendra Singh Thakur Mangal S. Rathore Khanjan Trivedi Vaibhav A. Mantri

Controlled environment agriculture technologies are traditionally applied to higher plants to enhance growth and cultivation periods, but such a concept has seldom been applied to seaweed aquaculture. A new dimension has been opened, wherein preliminary investigations in Ulva ohnoi revealed that continuous exposure (24 h) of light modulates chlorophyll-a fluorescence, carbohydrate content, and biochemical composition affecting the daily growth rate. DGR (daily growth rate) increased 2.6 times under continuous illumination for 24 h compared to the 12 h L/D photoperiod. Mg and carbohydrate contents were raised by 1.1 and 1.2 times, respectively, under continuous illumination. DGR formed a strong positive correlation with carbohydrate, protein, carotenoid, chlorophyll-a fluorescence, C, H, and Mg levels. A short cultivation cycle (15 days) was proposed to enable a consistent, continuous high growth and to avoid the induction of reproduction. The feedstock demand for bio-products, aquaculture feed, biomaterials, functional food, and food additives is registering unprecedented feedstock demand for Ulva. However, further detailed studies are desired to understand the seasonality and economic viability of scaling up this technique for commercial implementation.

Aquaculture Journal doi: 10.3390/aquacj5040027

Authors: Muhammad Abdul Aziz Al Mujahid Fahma Fiqhiyyah Nur Azizah Gun Gun Indrayana Nina Rachminiwati Yutaro Sakai Nobuyuki Yagi

Accurate prediction of shrimp body weight is critical for optimizing harvest timing, feed management, and stocking density decisions in intensive aquaculture. While prior studies emphasize environmental factors, operational management variables—particularly harvesting metrics—remain understudied. This study quantified the predictive importance of harvesting-related variables using 5 years of industrial-scale operational data from 12 ponds (5479 cleaned records, 34.94% retention rate). We trained seven machine learning models and applied three independent feature importance methods: consensus importance ranking, SHAP explainability analysis, and Pearson correlations. Main findings: Operational variables (days of culture: 2.833 SHAP, stocking density: 1.871, cumulative feed: 1.510) ranked substantially above environmental variables (temperature: 0.123, pH: 0.065, dissolved oxygen: 0.077). Partial harvest frequency showed bimodal clustering, indicating two distinct viable operational strategies. The Weighted Ensemble model achieved the highest performance (R2 = 0.829, RMSE = 4.23 g, MAE = 3.12 g). Model stability analysis via 10-fold GroupKFold cross-validation showed that the Artificial Neural Network (ANN) exhibited the tightest confidence bounds (0.708 g width, 27.7% coefficient of variation), indicating exceptional consistency. This is the first study to systematically analyze the importance of harvesting variables using SHAP explainability, revealing that operational management decisions may yield greater returns than marginal environmental control investments. Our findings suggest that operational optimization may be more impactful than environmental fine-tuning in well-managed systems.

Aquaculture Journal doi: 10.3390/aquacj5040026

Authors: Reindert Wieger Nauta Lestari Lakhsmi Widowati Restiana Wisnu Ariyati Sri Rejeki Adolphe Oscar Debrot

The Indonesian coastline holds significant potential for aquaculture but is increasingly vulnerable to climate change impacts such as land subsidence, salinization, and floodings. Ensuring stable income for local communities is essential, especially during extreme events like King Tides, which cause extensive floodings. This study assessed the productivity and economic returns of an agaroid seaweed monoculture compared to co-cultivation with Giant tiger prawn, Milkfish, and Barramundi during a King Tide. The experiment was conducted in conventional ponds with seaweed monoculture or combined with one of the three other commodities. The experiment ran from May until October in 2022 and was performed in triplicate. Floodings equalized water parameters. The results demonstrated that all systems provided stable income, with co-cultivation increasing profitability. Average revenues per hectare were USD 777 (seaweed monoculture), USD 832 (with shrimp), USD 1622 (with Milkfish), and USD 2014 (with Barramundi). Agar content was significantly higher in the seaweed monoculture, and gel strength was found to be significantly higher in the seaweeds co-cultivated with shrimp and Milkfish. Total agar production did not differ between the treatments. These findings suggest that integrated aquaculture systems can enhance income resilience while supporting food security in climate-impacted coastal zones. The approach offers a promising strategy for combining livelihood stability with adaptive coastal management and reduced environmental impact but needs to be tailored to local conditions.

Aquaculture Journal doi: 10.3390/aquacj5040025

Authors: Larissa Aparecida Moreira de Castro Tatiana da Gama Cunha Marco Shizuo Owatari

This study introduced a new small-scale semi-mechanized planting method for Kappaphycus alvarezii (Doty) and compared its efficiency to traditional methods. A semi-mechanized sewing (S-MS) device was designed to speed up the planting process using affordable materials. To validate the S-MS model, three different cultivation systems (S-MS method, tie-tie, and tube-net systems) using two color morphotypes of K. alvarezii were implemented, each in triplicate. The experiment spanned 40 days. Water quality and technical indicators were monitored, and data on material consumption and productivity were analyzed. The exclusive S-MS mechanism was successfully completed. The S-MS significantly reduced rope usage by 4.3 times per each propagule sewn to the main cable and planting time (S-MS = 1 min 12 s per meter) compared to the traditional method (tie-tie = 1 min 48 s per meter). Final biomass varied among treatments (p < 0.05), with the S-MS method showing a higher final biomass (15.26 ± 0.88 kg) with olive green K. alvarezii. The average daily growth rates (6.38%) were higher for the S-MS method with olive green K. alvarezii. The S-MS technique offers cost and time savings for seaweed farmers, making it a viable alternative to traditional methods, showed comparable productivity to tie-tie but superior efficiency and resource economy.

Aquaculture Journal doi: 10.3390/aquacj5040024

Authors: Giuseppe Portacci Isabella Parlapiano Marcella Narracci Antonella Di Leo

The management of fouling through exposure of mussels to air has become risky due to rising temperatures, as it can negatively impact product quality and farm productivity. Since the early 2000s, during air exposure, mussel farmers of the Mar Piccolo have been using high-density polyethylene (HDPE) cloths to cover mussels and prevent their overheating, thus contributing to marine litter from husbandry practices. In this context the aim of the present study was to evaluate whether the use of alternative types of air exposure facilities (wooden, without and with hemp cloth vs. galvanized iron, without and with HDPE cloth) can impact mussel condition index (CI). Since the most damaged mussels during exposure to air are those in contact with galvanized iron structures, for each facility, it was evaluated if there were differences between the mussels in contact with galvanized iron/wood racks and those near the sea surface. Overall, the results showed that the CI of mussels cleaned on wooden racks, ranging from 11.4 ± 2.7 to 12.5 ± 2.7, did not differ significantly from that of mussels before air exposure (CI = 13.1 ± 2.3), except for those near the sea surface without cover (CI = 9.6 ± 2.6). In contrast, a significant decrease in CI was observed in mussels cleaned on galvanized iron racks, with the lowest values observed in covered mussels (CI = 8.2 ± 2.3).

Aquaculture Journal doi: 10.3390/aquacj5040023

Authors: Menny M. Benjamin Christopher J. Carbon Heather L. Spalding Aaron Watson George S. Hanna Laura M. Kasman

The lack of an established seaweed aquaculture industry in the Atlantic Southeast reflects the persistent challenges in identifying macroalgal species that can consistently produce year-round under regional environmental conditions. As a result, in this study, locally abundant Charlestonian Ulva spp. were selected as sustainable algal candidates for a pilot investigation, due to their resilience to abiotic (e.g., seasonal changes in temperature and nutrients) and biotic (e.g., predation and epiphytes) factors, thus allowing for practical land-based aquaculture. Ulva spp. were analyzed for their seasonal biomass and potential bioremediation applications using the existing land-based aquaculture infrastructure of the SCDNR in Charleston, South Carolina. The biomass of tank-cultivated Ulva spp. was monitored on a biweekly basis for 16 months and was found to be highest (31.8 kg) in the spring, increasing by 22% in just two weeks as water temperatures rose. A synthetic nutrient fertilizer was incorporated into aquaculture at the latter stages of this study to observe the effects on algal biomass while simulating an anthropogenic event. Interestingly, inorganic supplementation did not induce growth but was absorbed by the algal tissue, significantly lowering the δ15N to <7‰. Additionally, Vibrio spp. bacteria proliferated following the inorganic nutrient spike, while coliform populations decreased. Biochemical composition analyses comparing tank-cultivated and wild in situ Ulva spp. revealed variations in essential trace element (e.g., potassium: tank—19,530; wild—5520 mg/kg) concentrations, yet shared similar trace metal (e.g., arsenic: tank—4.47; wild—4.52 mg/kg) and pesticide (e.g., DEET: tank—0.048; wild—0.040 mg/kg) concentrations. This is the first reported macroalgal aquaculture research in South Carolina and serves as a pilot study for future research or commercialization in the Lowcountry and the greater southeastern coastal communities of the United States.

Aquaculture Journal doi: 10.3390/aquacj5040022

Authors: Marcel Afonso Provenzi Gislaine Fongaro Juliano De Dea Lindner Itaciara Larroza Nunes Beatriz Pereira Savi Lucas Zanchetta Svetoslav Dimitrov Todorov Michael Leonidas Chikindas Marilia Miotto

Bivalve molluscs represent an important food source and have a significant economic impact through their commercialization in many countries. As high-capacity filter feeders, they can bioaccumulate contaminants and pathogens, creating tangible consumer health risks. This study presents the first comprehensive patent landscape of bivalve mollusc decontamination technologies indexed in international patent databases (Espacenet). The survey identified 30 patents filed between 1989 and 2025. Unlike reviews based solely on scientific literature, this work provides, for the first time, a global mapping of technological developments aimed at enhancing the safety of bivalves-derived foods. The analysis highlights depuration as the predominant technology, which continues to be refined and optimized. It also reveals the emergence of disruptive approaches—such as photodynamic sterilization, the use of probiotics, immunopotentiators, natural antimicrobial compounds, and genetic hybridization—developed to preserve the viability and sensory quality of the organisms. The novelty of this study lies in providing a technological overview of innovation within the aquaculture sector, emphasizing the transition from conventional methods to cleaner, integrated, and sustainable technologies. Furthermore, the research identifies the advancement of hybrid decontamination systems that combine microbiological efficiency, environmental preservation, and commercial value, contributing to safer and more technologically advanced shellfish production.

Aquaculture Journal doi: 10.3390/aquacj5040021

Authors: Eugenio Alberto Aragón-Noriega Edgar Alcántara-Razo José Adán Félix-Ortiz Samuel Angiee Ayón-Jiménez

Parameterizing nonlinear models presents an ongoing challenge in fisheries and aquaculture research. While additive and multiplicative error structures have been traditionally applied, a more recent alternative—the observed error structure—is gaining increasing acceptance. This study aimed to analyze the variability of individual growth during the early developmental stages of totoaba (Totoaba macdonaldi), shrimp (Penaeus vannamei), and pearl oyster (Pteria sterna). The observed variance was incorporated as a central component for parameterizing individual growth models. All three datasets were derived from controlled laboratory conditions. Information theory was applied to identify the most appropriate variance criterion (observed, additive, or multiplicative). The Schnute model, case 1, was utilized to estimate the growth curve for each species. Distinct growth patterns were observed: sigmoid in totoaba, rectilinear in shrimp, and exponential in pearl oyster. These findings indicate that incorporating observed variability at each age enhances the parameterization of individual growth models across diverse taxonomic groups, including fish, crustaceans, and mollusks.

Aquaculture Journal doi: 10.3390/aquacj5040020

Authors: Daercy Maria Monteiro de Rezende Ayroza Mauro Parolin Bruna Larissa Maganhe Eduardo Gomes Sanches

We investigated the occurrence of Radiospongilla inesi in a tilapia aquaculture facility located at the Chavantes Reservoir, Paranapanema River, Brazil. Specimens were collected from both artificial (net cages) and natural substrates along the reservoir margins in October and November 2024. Morphological analyses of 8 sponge samples, including 20 structures per sample (gemmules, megascleres, microscleres and spicules), identified the species as Radiospongilla inesi (Spongillidae). This is the third documented record of R. inesi in Brazil, and the first within the Paraná River Basin and in aquaculture net cage systems. Morphological features were consistent between individuals from natural and artificial substrates, although gemmules were absent in specimens colonizing the cages. The proliferation of R. inesi poses biofouling challenges by obstructing cage mesh openings, reducing water flow and dissolved oxygen levels, and potentially compromising fish welfare and production efficiency. These impacts increase operational costs and highlight the need for sustainable management strategies in freshwater aquaculture. Additionally, this study raises questions regarding the species’ native status in the Paraná Basin versus potential invasive dispersal, emphasizing the need for further ecological and distributional investigations. Potential dispersal mechanisms and possible biofouling impacts are discussed, with recommendations for future quantitative and molecular studies.

Aquaculture Journal doi: 10.3390/aquacj5040019

Authors: Ram C. Bhujel Patcharee Kaeoprakan Raquel Codina Moreno Óscar Castro Eva León Alvira Insaf Riahi

Shrimp farming often suffers due to high mortalities and poor growth. Mycotoxins can be one of the causes but often underestimated. BIŌNTE® QUIMITŌX® AQUA PLUS, an anti-mycotoxin additive (AMA) was tested to assess its efficacy and determine the best dose for Pacific white shrimp (Litopenaeus vannamei). Four treatments (0, 1, 2, and 3 g/kg of diet) were randomly allocated in 12 aquaria during larval rearing (day 1–20) and 12 fiberglass tanks during subsequent grow-out (day 21–111). Results showed positive impacts on feed conversion, protein efficiency, survival, and growth. A decreasing trend in FCR and increasing trend in PER with the increase in AMA dose. The higher the dose, the better was the immunity as indicated by the survival of shrimp against bacterial challenge. However, the survival and growth showed significant quadratic relationships indicating that the dose of 1.4 g/kg can have the highest daily weight gain (66.7 mg) and the dose of 2.5 g/kg results in the highest survival (60.3%) which is more than double the survival of the control group (27.3%). Therefore, the doses between 1.4 and 2.5 g/kg of feed are recommended for the grow-out phase to enhance growth and survival of shrimp. However, further studies should be conducted in outdoor pond conditions for varying feeding regimes, contamination levels and stocking densities.

Aquaculture Journal doi: 10.3390/aquacj5040018

Authors: Md. Naim Mahmud Abu Ayub Ansary Farzana Yasmin Ritu Neaz A. Hasan Mohammad Mahfujul Haque

Aquaculture has rapidly become a vital sector for ensuring global food security by meeting the growing demand for animal protein. Bangladesh, one of the world’s leading aquaculture producers, recorded a production of 4.91 million MT in 2022–2023, largely driven by inland farming systems. Despite this remarkable growth, the sector is highly vulnerable to disease outbreaks, which are aggravated by different factors. Pathogens such as bacteria, viruses, fungi, and parasites cause significant losses, while conventional disease diagnosis in Bangladesh still depends mainly on visual assessment and basic laboratory techniques, limiting early detection. This narrative review highlights recent advances in diagnostics as molecular tools, immunodiagnostics, nanodiagnostics, machine learning, and next-generation sequencing (NGS) that are widely applied globally but remain limited in Bangladesh due to infrastructure gaps, lack of skilled manpower, and resource constraints. Current treatment strategies largely rely on antibiotics and aquaculture medicinal products (AMPs), often misused without proper diagnosis, contributing to antimicrobial resistance (AMR). Promising alternatives, including probiotics, immunostimulants, vaccines, and enhanced biosecurity, require greater adoption and farmer awareness. The near-term priorities for Bangladesh include standardized disease and AMR surveillance, prudent antibiotic stewardship, phased adoption of validated rapid diagnostics, and investment in diagnostic and human capacity. Policy-level actions, including a national aquatic animal health strategy, stricter antimicrobial regulation, strengthening diagnostic infrastructure in institution, are crucial to achieve sustainable disease management and ensure long-term resilience of aquaculture in Bangladesh.

Aquaculture Journal doi: 10.3390/aquacj5030017

Authors: Andrew Watterson

A global debate is underway about how to achieve economic growth, which has led to a push for even greater ‘better regulation’ than already exists in the US and UK, including Scotland. ‘Better regulation’ can include softer regulation, less regulation, or even deregulation. Another regulatory model involves the precautionary principle and there is tension between the two. The ‘better regulation agenda’ has influenced the environmental quality standards adopted for emamectin benzoate in Scottish sea lice treatment. To explore how these complex regulatory models have been used or advocated for and why over 25 years, a process tracing analysis focusing on Scottish Government and Parliament web entries was conducted. Such an analysis has both strengths, providing new perspectives, and weaknesses, regarding the possible quality and extent of information available. The results reveal the ‘better regulation’ model in practice was initially adopted in the 2000s, supported by Scottish Government advisors and implemented by its regulators. Gradually, however, the model was challenged, at times, by researchers, regulators, Members of the Scottish Parliament, environmental non-governmental organizations, and by investigative journalists. This resulted in new environmental quality standards on emamectin benzoate being proposed, then sometimes tightened or blocked. Hence, ‘better regulation’ remains highly influential in the sector, with the fish farming industry able to weaken precautionary policies and enforcement in practice, directly and indirectly.

Aquaculture Journal doi: 10.3390/aquacj5030016

Authors: Tanisha Nayak Debabrata Panda Namita Naik Santosh Kumar Udgata Dharitri Choudhury Sovan Sahu Bindu R. Pillai

CIFA-GI Scampi® is a genetically improved, fast-growing strain of giant river prawn (Macrobrachium rosenbergii) developed by ICAR-Central Institute of Freshwater Aquaculture. Each year, selected broodstock are reared family-wise in nylon hapas for 3–4 months before use as parents for the next generation. However, this group rearing phase (GR) results in loss of quality broodstock due to aggression and cannibalism. This study evaluated individual rearing (IR) as an alternative to group rearing (GR). GR involved rearing of males or females in separate hapas, while IR placed males and females in separate hard plastic mesh boxes in ponds (18 boxes each). Results showed significantly higher average daily weight gain in GR, but IR achieved 100% survival for both sexes, compared to 50% (males) and 77.8% (females) in GR. No significant differences were observed in female maturity or male morphotypes (small male and no claw morphotypes). Given the markedly higher survival in IR, it is a viable alternative for post-selection rearing to minimize loss of valuable broodstock in the selective breeding program.

Aquaculture Journal doi: 10.3390/aquacj5030015

Authors: Divas Karimanzira

For aquaculture systems, maximizing feed efficiency is a major challenge since it directly affects growth rates and economic sustainability. Feed is one of the largest costs in aquaculture, and feed waste is a significant environmental issue that requires effective management strategies. This paper suggests a novel approach for optimal fish feeding in pond aquaculture systems that integrates vision language models (VLMs), optical flow, and advanced image processing techniques to enhance feed management strategies. The system allows for the precise assessment of fish needs in connection to their feeding habits by integrating real-time data on biomass estimates and water quality conditions. By combining these data sources, the system makes informed decisions about when to activate automated feeders, optimizing feed distribution and cutting waste. A case study was conducted at a profit-driven tilapia farm where the system had been operational for over half a year. The results indicate significant improvements in feed conversion ratios (FCR) and a 28% reduction in feed waste. Our study found that, under controlled conditions, an average of 135 kg of feed was saved daily, resulting in a cost savings of approximately $1800 over the course of the study. The VLM-based fish feeding behavior recognition system proved effective in recognizing a range of feeding behaviors within a complex dataset in a series of tests conducted in a controlled pond aquaculture setting, with an F1-score of 0.95, accuracy of 92%, precision of 0.90, and recall of 0.85. Because it offers a scalable framework for enhancing aquaculture resource use and promoting sustainable practices, this study has significant implications. Our study demonstrates how combining language models and image processing could transform feeding practices, ultimately improving aquaculture’s environmental stewardship and profitability.

Aquaculture Journal doi: 10.3390/aquacj5030014

Authors: Vimala Balasubramaniam Devi-Nair Gunasegavan Rathi Suraiami Mustar June Chelyn Lee

Aquaculture is the fastest-growing food production sector and plays a pivotal role in global food security. However, the reliance on conventional fishmeal and fish oil in aquafeeds raises sustainability concerns due to overfishing, high costs, and ecological burden. This review explores the valorisation of microalgae as a sustainable and functional alternative for aquafeed development. Microalgae are rich in proteins, polyunsaturated fatty acids, bioactive compounds, and pigments that support aquatic animal growth, immunity, and product quality. We critically examine the integration of green technologies, including cultivation systems, biomass harvesting, and eco-friendly extraction methods for optimising microalgal biomass and bioactive recovery. The review also discusses recent innovations in bioremediation and circular aquaculture systems, highlighting the role of microalgae in reducing nutrient discharge, carbon footprint, and operational cost. Challenges such as scalability, digestibility, and economic feasibility are also addressed, providing insight into pathways toward industrial adoption. This review aims to provide an updated and holistic perspective on microalgae-based aquafeeds in advancing sustainable aquaculture practices.

Aquaculture Journal doi: 10.3390/aquacj5030013

Authors: Cecilie I. Lie Carlos Zarza Sverre B. Småge Pablo Ibieta Pablo Ibarra Linda B. Jensen

The emergence and spread of pathogens pose significant challenges to the sustainability and productivity of aquaculture globally. For the Chilean salmon farming industry, salmonid rickettsial septicemia (SRS), caused by the facultative intracellular bacterium Piscirickettsia salmonis, constitutes one of the main disease challenges. In this study, the efficacy of various oral doses of florfenicol (FFC) (5, 7.5, and 10 mg/kg BW/day) against SRS was assessed in Atlantic salmon, when treatment was initiated at an early stage of infection. Since salmonids infected with P. salmonis typically lose appetite as the disease progresses, and the therapeutic FFC dose is dependent on a normal specific feeding rate (SFR), the treatments were administered 5 days post-challenge (DPC5). On the day of challenge, experimental fish were intraperitoneally (IP) injected with 0.2 mL of P. salmonis genogroup LF-89 inoculum (9.07 × 107 CFU mL−1). Fish mortality, behavior, clinical signs of disease, feed intake and SFR were monitored throughout the study. Conclusions: An important finding in this study was that all tested antibiotic doses halted disease progression and prevented mortality in fish challenged with P. salmonis when administered DPC5. In the control group, mortality reached 32.2% with fish displaying clinical signs of SRS.

Aquaculture Journal doi: 10.3390/aquacj5030012

Authors: Menaga Meenakshisundaram Jimmy B. Mboya Felix Sugantham Akshaya Panigrahi Juliana L. Gamba Sevgan Subramanian Shaphan Y. Chia Dennis Beesigamukama Jonathan Munguti Erick Ogello Rodrigue Yossa Chrysantus M. Tanga

This study investigated the effects of integrating biofloc with microalgae on growth performance and immune gene expression in red tilapia (Oreochromis sp.). The experiment consisted of four treatments: C (Biofloc), T1 (Chlorella vulgaris and Nannochloropsis sp.; 1:1), T2 (Biofloc + Chlorella vulgaris and Nannochloropsis sp.; 1:1), T3 (Biofloc + Chlorella vulgaris and Nannochloropsis sp.; 2:1) in 500 L plastic tanks for 60 days. T2 and T3 exhibited the lowest ammonia and nitrite levels, respectively. T3 exhibited the highest chlorophyll a and chlorophyll b levels, while T2 showed the highest carotenoid content. T2 showed the highest weight gain (142 ± 0.7 g) and SGR (1.61 ± 0.02) and the lowest FCR (1.79 ± 0.009). T2 exhibited the highest gene expression levels in the intestine, with 7.8-fold upregulation of the cathepsin L (ctsl) gene, 3-fold upregulation of toll-like receptor 7 (tlr7), 6.7-fold upregulation of interleukin-1 b (il-1b), 4.7-fold upregulation of tumor necrosis factor-alpha (tnf-a), and 2.8-fold upregulation of metallothionein (mt). In the head kidney, the mt upregulation was highest in T3 (7.2-fold), while tnf-a and tlr7 upregulations were highest in T2 (5.9-fold and 5-fold, respectively). In the liver, the gene expressions were highest in T3, with 6.4-fold upregulation of mt, 5-fold upregulation of ctsl, 2.7-fold upregulation of tlr7, 3-fold upregulation of il-1b, and 5.4-fold upregulation of tnf-a. These results suggest a synergistic effect of algae and bacteria on immune and antioxidative capacity in red tilapia.

Aquaculture Journal doi: 10.3390/aquacj5030011

Authors: Ilias Ahmed Mohammad Abu Baker Siddique Shanur Jahedul Hasan Mohammad Mahfujul Haque Md. Mahmudul Hasan A. K. Shakur Ahammad

Selenium nanoparticles (SeNPs), with their high absorption and antioxidant properties, hold promise as feed additives in aquaculture, enhancing growth and reproductive health in fish. This review evaluates how selenium nanoparticles influence growth and reproductive traits in Asian seabass (L. calcarifer). Using the PRISMA approach, we examined the impacts of selenium nanoparticles (SeNPs) on the growth performance and gonadal development of Asian seabass (L. calcarifer) by synthesizing findings from the existing literature. Meta-analysis explored that selenium nanoparticles (SeNPs) supplementation significantly improved specific growth rate (SGR) (pooled effect size = 3.97; 95% CI: 3.68–4.26) and feed conversion ratio (FCR) (pooled effect size = 0.81; 95% CI: 0.75–0.86), with low heterogeneity. Regarding reproductive outcomes, SeNPs enhanced gonadal development, sperm quality, and steroidogenesis. Significant improvements were observed in gonadosomatic index (effect size = 0.5), fertilization rate (0.6), and testosterone levels (0.5), along with a reduction in abnormal embryogenesis (−0.3) (p < 0.05). While an optimal level of SeNPs is effective for enhancing aquaculture performance, excessive use may lead to toxicity; therefore, their economic viability, environmental impact, and sustainability in large-scale aquaculture warrant further investigation. This review provides insights for researchers, policymakers, and industry stakeholders on the potential of SeNPs in advancing sustainable aquaculture through fish productivity and reproductive performance.

Aquaculture Journal doi: 10.3390/aquacj5030010

Authors: Yael José Trejo-Sánchez Graciela María Pérez-Jiménez Gabriel Núñez-Nogueira Luis Daniel Jiménez-Martínez Otilio Méndez-Marín Gloria Gertrudys Asencio-Alcudia Uriel Rodríguez-Estrada Rafael Martínez-García Carlos Alfonso Álvarez-González César Antonio Sepúlveda-Quiroz

The objective of this work was to evaluate the effects of three commercial diets for ornamental fish (BIOMAA Spiruflake® (T1), Tetra TetraMin Tropical Flakes® (T2), LOMAS tropical fish flakes® (T3)) compared to a balanced feed for trout (Silver Cup TM (T4)) on the growth, survival, digestive enzyme activity, and intestinal and liver morphology of guppy (Poecilia reticulata) fry after 31 days of feeding. The highest growth was in T2 (0.101 ± 0.004 g) and T4 (0.084 ± 0.008 g) (p < 0.05). Fish fed with T1, T2, and T4 presented the greatest total length. T4 (98 ± 2.828%) and T1 (96 ± 5.656%) had the highest survival. Fish fed with T2 and T4 showed the best growth index values (AWG, SGR, FCR). T4 showed greater alkaline protease, trypsin, and chymotrypsin activity and better in vitro digestibility. The fish fed the T4 diet had the lowest intestinal fold height and the smallest hepatocyte diameter. A cheaper aquaculture diet (T4) significantly improved guppy juvenile nutrition compared to ornamental feeds. Further research should focus on developing species-specific ornamental diets for enhanced fish welfare.

Aquaculture Journal doi: 10.3390/aquacj5020009

Authors: Gabriel Artur Bezerra Dara Cristina Pires André Luiz Watanabe Celso Carlos Buglione Neto Alex Júnio da Silva Cardoso Andre Rozemberg Peixoto Simões Hamilton Hisano

To meet the growing demand for sustainable aquaculture, the biofloc technology (BFT) system has emerged as a promising solution, offering high productivity, improved water use efficiency, and enhanced environmental and biosecurity performance. Economic and risk analyses are essential tools for identifying the key technical and economic factors that determine the profitability and long-term sustainability of aquaculture systems. This study aimed to evaluate the economic feasibility and the risk associated with Nile tilapia juvenile production in a BFT system. Economic viability indicators were calculated using real data on capital investment, operational costs, and zootechnical performance from a production cycle. Scenario analyses were conducted to assess the effects of fluctuations in input prices and survival rates on overall economic outcomes. Stochastic simulations were also conducted to determine the probabilities of economic results. The items with the greatest impact on costs were the acquisition of the greenhouse and fingerlings, representing 27.64% of the initial investment and 33.24% of the operating cost, respectively. The BFT system showed a positive net margin and profitability per production cycle, with the exception of the pessimistic scenario. The risk analysis demonstrated that in 87.29% of the simulations resulted in a positive profit. Thus, the production of tilapia juveniles in a BFT system is an economically viable investment. However, its success is contingent upon specific technical and market conditions, underscoring the need for careful management and context-specific planning.

Aquaculture Journal doi: 10.3390/aquacj5020008

Authors: Angel Algarra-Paredes Ana-Lucia Ortega-Larrea María-Julia Bordonado-Bermejo

The Green Agenda is a priority of the European Union. The development of environmentally friendly economic activities is high on the agenda of the EU institutions. Aquaculture is presented as an alternative activity to traditional fishing. For this reason, European funds have been allocated to promote aquaculture in the EU. The Court of Auditors of the EU has carried out the first complete audit on the efficiency of the financial resources received by the countries. This article analyzes the strengths and weaknesses of the aquaculture sector, the conclusions of the European Court of Auditors, and the main changes to be undertaken in the future. The reports conducted thus far are insufficient to establish measurable results. Additionally, these audits should be coordinated more effectively in terms of objectives and work plans to generate relevant data for the design of a European aquaculture policy that adequately addresses the sector’s needs.

Aquaculture Journal doi: 10.3390/aquacj5010007

Authors: Nhien Thi Nguyen Nam Hoang Tran

The rising scarcity and cost of fishmeal due to overfishing and environmental challenges demand alternatives. Black soldier fly (Hermetia illucens) larvae (BSFL) meal, with its nutritional value, shows promise as a sustainable supplement for aquaculture species. This study evaluated the effects of BSFL meal supplementation on growth performance, survival, feed conversion efficiency, and meat quality in juvenile swamp eels (Monopterus albus) initially weighing 4.0 ± 0.5 g. The eels were fed diets with 0% (control), 10%, 30%, and 50% BSFL meal for three months. Growth performance was assessed using the absolute growth rate (AGR) and the specific growth rate (SGR). Feed conversion ratios (FCRs), survival rates, and meat quality metrics, including fillet percentage, crude protein, and moisture content, were analyzed. Statistical differences among groups were evaluated using one-way ANOVA followed by Tukey’s post hoc test for pairwise comparisons. The 30% BSFL group exhibited superior performance, achieving the highest AGR and SGR (p < 0.05) and the lowest FCR (2.33 ± 0.03). Fillet percentage was highest in this group (27.3% ± 0.7%), with no significant differences in crude protein or moisture content. Survival rates were consistent across treatments (75.2–76.0%, p > 0.05). These results confirm that 30% BSFL supplementation optimally enhances productivity and meat quality in swamp eels, highlighting BSFL meal’s potential as a sustainable aquafeed alternative.

Aquaculture Journal doi: 10.3390/aquacj5010006

Authors: Hayin Tamut Robin Ghosh Kamal Gosh Md Abdus Salam Siddique

The expansion of aquaculture necessitates innovative disease detection methods to ensure sustainable production. Fish diseases caused by bacteria, viruses, fungi, and parasites result in significant economic losses and threaten food security. Traditional detection methods are labor-intensive and time-consuming, emphasizing the need for automated approaches. This study investigates the application of convolutional neural networks (CNNs) for classifying freshwater fish diseases. Such CNNs offer an efficient and automated solution for fish disease detection, reducing the burden on aquatic health experts and enabling timely interventions to mitigate economic losses. A dataset of 2444 images was used across seven classes—bacterial red disease, bacterial Aeromoniasis disease, bacterial gill disease, fungal disease, parasitic diseases, white tail disease, and healthy fish. The CNNs model incorporates convolutional layers for feature extraction, max-pooling for down-sampling, dense layers for classification, and dropout for regularization. Categorical cross-entropy loss and the Adam optimizer were used over 50 epochs, with continuous training and validation performance monitoring. The results indicated that the model achieved an accuracy of 99.71% and a test loss of 0.0119. This study highlights the transformative potential of artificial intelligence in aquaculture for enhancing food security.

Aquaculture Journal doi: 10.3390/aquacj5010005

Authors: Zhangwang Lu Jun Wang Donghuo Jiang Yan Wang Hui G. Jiang

The covert mortality nodavirus (CMNV), an emerging pathogen that infects several species severely in aquaculture, including marine shrimps, freshwater prawns, and crabs, has been detected in both wild Artemia and commercial Artemia cysts. Utilization of Artemia from unknown sources can impose considerable biosecurity risks in hatchery operations; therefore, effective hatching methods to eliminate the pathogenic potential from CMNV-positive (CMNV+) Artemia cysts are urgently needed. In this work, we assessed the efficacy of three treatment methods of disinfecting CMNV+ Artemia cysts during hatching: (1) decapsulation of Artemia cysts with Na2CO3 (sodium carbonate) and NaClO (sodium hypochlorite) at various durations before hatching; (2) application of different concentrations of formalin in hatching water; (3) combinations of decapsulating Artemia cysts and formalin-treated hatching water. Hatching CMNV+ Artemia with disinfected seawater only served as the control. The virus located on the cyst shells attached/infected Artemia larvae during hatching and remained active for a prolonged time of 7 days. The viral load of empty shells decreased with the decapsulation treatment time. After a 45 min treatment of decapsulation, CMNV on shells, as well as larvae, were eliminated successfully. Furthermore, decapsulation shortened the hatching time of the cysts from 19 h to 12 h. Ten ppm formalin in the hatching water could block the transmission of CMNV from the shells to the newly hatched larvae, although at this level it was insufficient to eliminate the virus from the shells completely. While use of 30 ppm formalin or higher dosage could eliminate CMNV, however, it also reduced the hatching rates of the Artemia cysts. A combination of decapsulation (treated with Na2CO3-NaClO for 15 min) and 10 ppm formalin in hatching water effectively eliminated the CMNV. This study developed a practical, effective, and reliable treatment method for hatching Artemia to ensure biosecurity in aquaculture hatcheries.

Aquaculture Journal doi: 10.3390/aquacj5010004

Authors: Silvia Gomez-Jimenez Elisa M. Valenzuela-Soto Julio C. Zamorano-Apodaca Luis A. Gamez-Alejo Cesar Muñoz-Bacasehua

High evaporation rates due to solar intensity and low precipitation could represent a challenging culture environment in northwestern Mexico, generating osmotic stress in shrimp due to high salinity. Bacterial infections by pathogenic Vibrio strains are highly virulent in shrimp culture. This study evaluated betaine aldehyde dehydrogenase (BADH) activity and glycine betaine (GB) levels in Litopenaeus vannamei under high salinity levels plus experimental infection with virulent Vibrio parahaemolyticus. At 35 ppt (control group) and 40 ppt after infection, GB levels increased two-fold in the gills except at 45 ppt and were significantly higher at 50 ppt. The highest GB levels were in the hepatopancreas of the uninfected group at 45 ppt. In the gills, BADH activity decreased after 2 h of exposure at 40 and 45 ppt; at 50 ppt, there was a significant increase in the uninfected groups. However, upon infection, activity increased at all salinities except 50 ppt. In the hepatopancreas of the uninfected groups, the highest activity was at 40 ppt and this was lowest at 50 ppt after 8 h. In the muscles, BADH was detectable at all salinities; infection caused an increase in its activity at 45 and 50 ppt. Despite sudden exposure to high salinity plus experimental infection, our results show that Litopenaeus vannamei does not inhibit BADH activity, allowing GB synthesis, which may play a role in shrimp survival under these conditions.

Aquaculture Journal doi: 10.3390/aquacj5010003

Authors: Nicole McCarty Jill M. Voorhees Michael E. Barnes David Bergmann

Disinfection of fish eggs with iodophor is a common biosecurity procedure. This study evaluated the effects of three concentrations of iodine on walleye (Sander vitreus) egg survival and bacterial loadings. Approximately five hours post fertilization, eggs from ten female walleyes were disinfected in active iodine concentrations of 0, 100, 200, and 400 mg/L for 10 min. There was a significant decrease in survival in the 200 mg/L treatment group compared to the 0 mg/L (control) and 100 mg/L groups. Near-total mortality occurred in the eggs receiving the 400 mg/L disinfection regime. Bacterial Colony Forming Units (CFU) were significantly reduced with any iodine disinfection compared to the control, but there was no significant difference in CFU among any of the iodine treatment concentrations. There was no relationship between egg survival and either pre- or post-disinfection CFU levels. These results indicate that 10 min treatments of active iodine at a concentration of 100 mg/L can be safely used to reduce bacterial loadings on newly spawned walleye eggs, but complete disinfection will not occur. Higher iodine concentrations, which lead to walleye egg mortality, do not further decrease bacterial numbers.

Aquaculture Journal doi: 10.3390/aquacj5010002

Authors: Thomas Wilke Slim Bendag Annalena Barth Tim Reinold Patrick Schubert

Comparable and reproducible research is needed to improve Pacific white shrimp (PWS) aquaculture. These experiments typically involve before-and-after measurements of the same individual for paired statistical testing. However, marking shrimp with external or internal tags is challenging, especially for juveniles. A possible alternative is to rear shrimp individually in single-shrimp systems. While such systems may also prevent competitive interactions, PWS are considered social animals and individual rearing may negatively affect social behavior. Therefore, the general goal of this study was to evaluate the effects of single-shrimp versus multi-shrimp systems on the survival, growth, and welfare of juvenile PWS using a randomized controlled trial with group sizes of one, three, and five individuals. We found that shrimp kept individually had a higher survival rate, higher final body weights and lengths, and longer antennae than shrimp kept in groups of three or five. The incidence of eye cataracts was not significantly different among groups. Based on these results, we conclude that the individual rearing of juvenile PWS has no negative effects on survival, growth, or welfare. Therefore, a single-shrimp system could be an alternative to individually marked shrimp to allow paired statistical testing in experimental trials, especially when using post-larvae or juvenile specimens.

Aquaculture Journal doi: 10.3390/aquacj5010001

Authors: Emilly Cordeiro Petillo Aline da Cunha Ferreira Christiane Patrícia Feitosa de Oliveira Lian Valente Brandão Thiago Marinho-Pereira Bruno Adan Sagratzki Cavero

The tambaqui (Colossoma macropomum) is Brazil’s most farmed native species, playing a crucial role in aquaculture. This study aimed to evaluate growth, hematological, biochemical, and body condition (Kn) parameters of tambaqui under two stocking densities in a recirculating aquaculture system (RAS). A total of 240 tambaqui (12.2 ± 4.1 g; 6.63 ± 0.73 cm) were distributed across six experimental units in two treatments (SD1 = 140 fish m−3; SD2 = 180 fish m−3) with three replicates. After 45 days, no significant differences were observed in water quality or zootechnical performance (p > 0.05), with final productivities of 8.64 ± 1.85 kg m3 and 9.46 ± 1.95 kg m3 for SD1 and SD2, respectively. Elevated plasma glucose, cholesterol, and triglyceride levels indicated energy reserve mobilization, suggesting some physiological response to higher stocking densities. However, other hematological and body condition parameters, including condition factor (Kn), indicated no significant adverse effects. These findings suggest that tambaqui can tolerate these stocking densities in RAS without compromising body condition, supporting the species’ intensive farming potential in controlled systems. This study highlights the importance of balancing productivity and physiological conditions in aquaculture management.

Aquaculture Journal doi: 10.3390/aquacj4040024

Authors: Erick Ogello Mavindu Muthoka Nicholas Outa

This review evaluates regenerative aquaculture (RA) technologies and practices as viable pathways to foster resilient, ecologically restorative aquaculture systems. The key RA technologies examined include modern periphyton technology (PPT), biofloc technology (BFT), integrated multitrophic aquaculture (IMTA), and alternative feed sources like microalgae and insect-based diets. PPT and BFT leverage microbial pathways to enhance water quality, nutrient cycling, and fish growth while reducing environmental pollutants and reliance on conventional feed. IMTA integrates species from various trophic levels, such as seaweeds and bivalves, to recycle waste and improve ecosystem health, contributing to nutrient balance and reducing environmental impact. Microalgae and insect-based feeds present sustainable alternatives to fishmeal, promoting circular resource use and alleviating pressure on wild fish stocks. Beyond these technologies, RA emphasizes sustainable practices to maintain fish health without antibiotics or hormones. Improved disease monitoring programs, avoidance of unprocessed animal by-products, and the use of generally recognized as safe (GRAS) substances, such as essential oils, are highlighted for their role in disease prevention and immune support. Probiotics are also discussed as beneficial microbial supplements that enhance fish health by promoting gut microbiota balance and inhibiting harmful pathogens. This review, therefore, marks an important and essential step in examining the interconnectedness between technology, agroecology, and sustainable aquaculture. This review was based on an extensive search of scientific databases to retrieve relevant literature.

Aquaculture Journal doi: 10.3390/aquacj4040023

Authors: Shubha Vij Yeng Sheng Lee Kathiresan Purushothaman Dean Jerry

Singapore’s aquaculture sector is critical to achieving the nation’s ‘30 by 30’ food security goal, which aims to produce 30% of its nutritional needs locally by 2030. However, the sector faces several significant challenges. Limited land and water resources, high operational costs, disease outbreaks, reliance on imported seedstock, and environmental impact are among the key issues. Additionally, the industry struggles with a shortage of skilled manpower and high dependency on foreign labour. This study explores these challenges in detail and suggests potential solutions to enhance the sustainability and productivity of Singapore’s aquaculture. Innovative farming techniques such as recirculating aquaculture systems (RASs) and vertical farming, advanced water quality management, and the adoption of renewable energy sources are recommended to address space and cost constraints. Developing local breeding facilities, enhancing education and training programs, and adopting sustainable practices are also crucial. The establishment of a national hatchery and increased investment in research and development (R&D) are essential for long-term growth. By implementing these strategies, Singapore can overcome the challenges in its aquaculture sector and ensure a sustainable future for local food production.

Aquaculture Journal doi: 10.3390/aquacj4040022

Authors: Md. Mehedi Alam Mohammad Mahfujul Haque Morena Santi

The rapid growth of pangasius and tilapia aquaculture has created export opportunities for Bangladesh; however, this industry is facing multiple barriers to becoming a competitive whitefish exporter in the international market. We analyzed a widely used conceptual framework and reviewed the available literature to unpack the barriers to pangasius and tilapia exports in mainstream global markets. Primary data were collected by interviewing 60 associated stakeholders to consolidate the research objectives. A meta-analysis of the literature and primary data revealed that pangasius and tilapia exporters face various internal (company and product barriers) and external (industry, market, and macroenvironment barriers) barriers. To overcome these barriers, the pangasius and tilapia industries need separate export-oriented policies and legislation to be developed by the competent authority, namely, the Department of Fisheries (DoF), which needs to provide common guidelines to meet international standards of aquaculture practices, food safety, quality, certification, and export markets. The DoF should ensure robust oversight through effective monitoring and surveillance mechanisms to implement the regulations and policies. Drawing insights from China and Vietnam’s experiences in responsible aquaculture practices, navigating export markets, and instituting aquaculture certification could provide invaluable lessons for Bangladesh. Using these lessons to overcome impediments could catalyze the flourishing of Bangladesh’s pangasius and tilapia sectors in the global whitefish market.

Aquaculture Journal doi: 10.3390/aquacj4040021

Authors: Demitri Lifgren Sarah M. Turner Timothy J. Welch Deborah Bouchard Mark P. Polinski

Preliminary evidence has showed an emergent serotype O3 (SO3) strain of Vibrio anguillarum to cause mortality in pre-smolt Atlantic salmon (Salmo salar) by injection with >105 colony forming units (cfus). Here, we sought to identify the susceptibility of Atlantic salmon post-smolts to this emergent strain by both injection and cohabitation to better understand transmission risk within cultured salmon and possibly between salmon and Atlantic menhaden (Brevoortia tyrannus), where this strain was identified. We identified that although mortality could be induced with a high-dose (>106 cfus) intraperitoneal injection of the emergent SO3 strain (cumulative mortality of 40%), post-smolt Atlantic salmon were highly refractory to a low dose (<106 cfus; cumulative mortality of 3%) or cohabitation exposure (no mortality). A qPCR assay targeting this strain was developed and analytically validated, revealing the limited presence of bacterial DNA in the spleen of low-dose-injected fish (2/36) and no detections in sampled cohabitants (0/70) across three timepoints during the 27-day challenge. These results suggest that although Atlantic salmon can succumb to high-dose artificial infections with V. anguillarum SO3, the risk of natural transmissibility and susceptibility of Atlantic salmon to this emergent strain is anticipated to be low.

Aquaculture Journal doi: 10.3390/aquacj4040020

Authors: Rafael Angelakopoulos Andreas Tsipourlianos Alexia E. Fytsili Themistoklis Giannoulis Katerina A. Moutou

European sea bass (Dicentrarchus labrax) is one of the most significant species farmed in the Mediterranean, yet a very perishable product. Its quality deteriorates rapidly as a result of three mechanisms: microbial activity, chemical oxidation, and enzymatic degradation. Microbial spoilage is the mechanism that contributes most to the quality deterioration of fresh and non-processed fish. To this end, our study aims to identify for the first time the combined effect of aquatic environment and harvest method on the composition and trajectory at storage at 0 °C of the European sea bass skin microbiome. Sampling was performed in two commercial fish farms in Western (WG) and Central Greece (CG) where fish were harvested using different methods: direct immersion in ice water or a mixture of slurry ice; application of electro-stunning prior to immersion in ice water. Samples were collected on harvest day and one week post-harvest. To profile the bacterial communities in the fish skin, 16S ribosomal RNA gene sequencing was used. The results and the following analyses indicated that the aquatic environment shaped the original composition of the skin microbiome, with 815 ASVs identified in the WG farm as opposed to 362 ASVs in the CG farm. Moreover, Pseudomonas and Pseudoalteromonas dominated the skin microbiome in the WG farm, unlike the CG farm where Shewanella and Psychrobacter were the dominant genera. All these genera contain species such as Shewanella putrefaciens, Pseudomonas aeruginosa, Pseudoalteromonas spp., and Psychrobacter sp., all of which have been implicated in the deterioration and spoilage of the final product. The different harvest methods drove variations in the microbiome already shaped by the aquatic environment, with electro-stunning favoring more diversity in the skin microbiome. The aquatic environment in combination with the harvest method appeared to determine the skin microbiome trajectory at storage at 0 °C. Although Shewanella had dominated the skin microbiome in all samples one week post-harvest, the diversity and the relative abundance of genera were strongly influenced by the aquatic environment and the harvest method. This study sheds light on the hierarchy of the factors shaping the fish skin microbiome and their importance for controlling post-harvest quality of fresh fish.

Aquaculture Journal doi: 10.3390/aquacj4040019

Authors: Nguyen Huu Yen Nhi Trinh Thi Lan Kartik Baruah Torbjörn Lundh Anders Kiessling

A 60-day feeding experiment was conducted to examine whether (i) soybean meal (SBM) protein in the diet of Nile tilapia (Oreochromis niloticus) can be replaced with protein from spent brewer’s yeast (SBY); (ii) co-rearing with biofloc alters fish growth, feed conversion and protein efficiency compared with rearing in clear water; and (iii) accumulated protein quantity and quality in biofloc acts as a possible feed source for the fish in periods of low feed intake. The fish were reared in either a bio-recirculating aquaculture system (Bio-RAS) or a clear-water RAS (Cw-RAS). In Bio-RAS, the mechanical and biological filters used in Cw-RAS were replaced with an open bioreactor that delivered heterotrophic-based biofloc to the rearing tanks and also acted as a sedimentation trap for effluent water before recirculating it back into the rearing unit. The fish were fed four iso-nitrogenous and iso-energetic diets (~28% crude protein, ~19 MJ kg−1 gross energy) in which SBM protein was replaced with increasing levels of SBY, with triplicate tanks per inclusion level. The results revealed that average fish growth was greater in a biofloc environment compared with clear water and also greater at higher inclusion levels of SBY. However, in both rearing environments, fish growth displayed a second-degree polynomial distribution with increasing SBY inclusion level, with a peak between 30% and 60% inclusion. Fish in the biofloc environment showed better feed conversion ratio and protein retention, likely through ingesting both given feed and biofloc. Biofloc contained a significant amount of accumulated protein with a high biological profile, thereby constituting a possible feed reserve for the fish. A conclusion underlined by the apparent improved feed conversion of Bio-RAS reared fish, where that ingestion of biofloc will reduce the need for external feed per unit growth.

Aquaculture Journal doi: 10.3390/aquacj4040018

Authors: Pablo Sanchez-Jerez Javier Atalah Ingeborg Mathisen Sætra Thomas Bøhn Bjorn-Steinar Saether Torild Johansen Nigel Keeley Terje van der Meeren Pål Arne Bjørn

Coastal aquaculture and local fisheries interact in shared marine environments, influencing each other synergistically and/or antagonistically. Salmon farming, notably with open-net sea cages along the Norwegian coast, attracts wild fish due to increased food availability from uneaten feed, but it also exposes wild fish to farm emissions like waste and toxic chemicals (de-lice treatments, antifouling and medical agents). The attraction behaviour of wild fish can impact fatty acid composition in fish tissues, influenced by the high terrestrial fat content in salmon aquafeed. We study how the Atlantic cod, aggregating around salmon farms in a subarctic fjord in Northern Norway, can be affected, potentially altering their natural diet and fatty acid profiles. Our study compares the muscle-tissue fatty acid compositions of cod caught near aquaculture facilities (impact) versus fish caught in neighbouring fjords (control), and we hypothesise decreased omega-3 fatty acids near farms. The analysis revealed no significant differences in the fatty acid concentrations or categories between the impacted and control fish, challenging our initial expectations. However, differences were found for C18:1(n9)t (elaidic acid), with a higher value in the impacted fish. These findings suggest that salmon farming’s influence on cod’s fatty acid profiles in the flesh (i.e., relevant for the nutritional quality of the fillets that consumers eat) may be limited or minimal despite their aggregative behaviours around farms. The threshold levels of salmon feed consumed by wild cod before it affects the quality and survival of, e.g., sperm or other life stages, are not known and require new investigations. This study underscores the complexity of interactions between aquaculture and wild fisheries, impacting both ecological dynamics and consumer perspectives on seafood quality and health benefits.

Aquaculture Journal doi: 10.3390/aquacj4040017

Authors: Oghenefejiro Adagha Jerimoth Kesena Ekelemu Oster Francis Nwachi Arnold Ebuka Irabor

This study evaluates the effects of Christmas melon (Laganaria breviflorus)-based diets on the growth and hematology of African catfish (Clarias gariepinus) after a 6 (six)-month feeding trial. A total of 240 C. gariepinus juveniles with an average weight of 10.68 g were procured from the Fisheries and Aquaculture Department Hatchery Unit for the feeding trial. After acclimating for a week (7 days) using 2.00 mm Coppens feed (45% CP) twice per day, the fish samples were randomly distributed into 12 tarpaulin tanks of 4 ft × 4 ft × 4 ft with a 200 L water holding capacity (four (4) different treatments presented in triplicate). Twenty (20) fish per tank were fed twice daily with the compounded feed with varying dietary inclusion levels of Christmas melon (0% (control), 5%, 10% and 15%). The weights and lengths of the sampled fish were measured biweekly to determine the growth performance, while hematological parameters, such as the packed cell volume, erythrocytes, hemoglobin, and leucocytes were determined midway through and at end of the feeding trial. The data collected were analyzed using ANOVA, and the results revealed the optimum growth and nutrient utilization and hematological and serum biochemical parameters of C. gariepinus in T3. The length–weight relationship results revealed that the fish exhibited an isometric growth pattern with B-values above 3 across the treatments. In conclusion, the results obtained in this study revealed that Christmas melon (L. breviflorus) could replace wheat offal by up to 10% in the diet of C. gariepinus without negative effects on the obtained optimal growth performance, hematological parameters, or serum biochemistry.

Aquaculture Journal doi: 10.3390/aquacj4040016

Authors: Mayra da Silva Gonçalves Andrezza Carvalho Jorge Santos Mariana Holanda Luís Henrique Poersch César Serra Bonifácio Costa

The incorporation of aquaponics into saline integrated multitrophic aquaculture (IMTA) systems, employing biofloc technology (BFT), relies on the cultivation of halophytes capable of withstanding the physical–chemical conditions created by the unique microbial communities in BFT systems. This study aimed to evaluate the integration of the halophyte Salicornia neei with tilapia (Oreochromis niloticus) and marine shrimp (Litopenaeus vannamei) reared in BFT systems dominated by chemoautotrophic (CHE) and heterotrophic (HET) microorganisms over a period of 84 days in southern Brazil. Each BFT treatment had three replicates, composed of IMTA units. The stocking densities were 400 ind. m−3 (17 m3 circular tanks), 44 ind. m−3 (4 m3 circular tanks), and 30 ind. m−2 (4.8 m2 hydroponic benches) for shrimp, fish, and halophyte, respectively. The highest S. neei individual shoot production (up to 31 g per 30 days) was observed in the CHE treatment, along with favorable agronomic characteristics, possibly due to overall elevated nitrate (98.41 mg N−NO3 L−1) and phosphate concentrations (4.62 P−PO4 L−1). Shrimp in the CHE treatment displayed higher average final weight, specific growth rate, productivity, and survival (11.24 g, 2.88% day−1, 3.86 kg m−3, and 90%, respectively) compared to the HET treatment. Results indicated no significant difference in tilapia zootechnical performance between treatments.

Aquaculture Journal doi: 10.3390/aquacj4030015

Authors: Silas Ochieng Erick Ogello Kevin Obiero Maureen Cheserek

This paper analyzes the factors influencing households’ resilience capacities to shocks within Kenya’s fisheries and aquaculture sectors and draws from primary data collected from 419 fish-dependent households across Kisumu, Busia, Mombasa, and Kilifi counties. The sample represents a total of 48,000 fishing households. The study adopted a quasi-longitudinal design and computed the household resilience capacity index (RCI) using the resilience index measurement and analysis (RIMA-II) model. The results indicate that male-headed households’ mean household RCI scores (mean = 45.07 ± 10.43) were statistically significant to that of female-headed households (mean = 38.15 ± 9.25), suggesting that female-headed households are associated with lower resilience capacities than male-headed households. Moreover, the study identifies differences in resilience levels across various occupations within the sector. For instance, RCI scores among fish traders (mean = 40.71 ± 9.97), a function performed mainly by women, statistically differed (p < 0.005) from male-dominated cage farming (mean = 48.60 ± 10.47), whereas RCI scores at the production level for fisher folks (mean = 44.89 ± 10.09) and pond farmers (mean = 44.04 ± 12.07) showed no statistical difference (0 > 0.05. Additionally, households with more income sources tend to have higher resilience capacities. Seasonality in fishing cycles limited households’ ability to recover from climate-induced shocks; the more months without fishing activity, the less the odds of recovery from shocks (OR = 0.532, 95% CI [0.163, 0.908], p = 0.022). Furthermore, households that lacked guaranteed market access and inputs during COVID-19 were less likely to recover during and after the shocks (OR = 0.401, 95% CI [0.161, 0.999], p = 0.05). Households organized in cooperatives with better access to credit showed a higher chance of recovery. The study recommends (a) adopting gender-sensitive approaches in fisheries and aquaculture interventions to empower women in trade, (b) strengthening policies to enhance access and adoption of climate-smart technologies such as cage fish farming, (c) promoting livelihood diversification to sustain households’ income during fishing off-seasons, and (d) enhancing market linkages in the fish value chain through coordinated producer organizations. Further research should explore the possibilities of introducing index-based weather insurance and other tested suitable safety nets for the fisheries and aquaculture sector.

Aquaculture Journal doi: 10.3390/aquacj4030014

Authors: Cecília de Souza Valente Arielly Fávaro Mendes Caio Henrique do Nascimento Ferreira Bernardo Baldisserotto Berta Maria Heinzmann André Martins Vaz-dos-Santos Eduardo Luis Cupertino Ballester

This study evaluated the anaesthetic potential of clove basil (Ocimum gratissimum) essential oil (EO-OG) in the post-larvae (PLs) of M. rosenbergii. The PLs were individually transferred to aquariums (500 mL) containing 50, 100, 150, 200, or 300 μL L−1 EO-OG. A sixth group of PLs was exposed to freshwater only, and a seventh group was exposed to the highest concentration of ethanol used to dilute EO-OG. Upon reaching the anaesthesia stage, the PLs were transferred to aquariums (500 mL) with freshwater only to evaluate the recovery time. The shortest sedation times were observed at 200 (15.98 s) and 300 μL L−1 (25.85 s). The shortest anaesthesia time was observed at 200 μL L−1 (22.52 s). The longest recovery time was observed at 100 μL L−1 (1367.10 s); the shortest recovery time was observed at 150 μL L−1 (630.10 s). No mortality or adverse effects were observed in any experimental group. The concentration of 150 μL L−1 resulted in sedation (49.24 s), anaesthesia (80.10 s), and recovery (630.10 s) times within those suggested as adequate for freshwater prawn farming. This research demonstrated the sedative and anaesthetic properties of EO-OG and its potential application in prawn farming. This study recommends using 150 μL L−1 of EO-OG in M. rosenbergii PLs.

Aquaculture Journal doi: 10.3390/aquacj4030013

Authors: Evans Kamwi Simasiku Kudakwashe Hove Margaret Ndatoolewe Kanyeme Simon Kamwele Awala Kenneth Kamwi Matengu Titus Iipinge Iita

This study compared the effects of three supplementary diets—egg yolk, Artemia, and commercial pellets with 48% crude protein—on the growth performance and survival rate of redbreast tilapia (Coptodon rendalli) under intensive culture conditions at the Kamutjonga Inland Fisheries Institute in the Kavango East region of Namibia. The study was conducted from December 2023 to January 2024 using a complete randomized design replicated thrice. Results showed that fish fed with commercial pellets exhibited the highest specific growth rate (1.39 ± 0.80%) compared to egg yolk (0.94 ± 0.54%) and Artemia (0.33 ± 0.19%). Commercial pellets also had the best survival rate (76.19 ± 43.099), compared to egg yolk and Artemia (70.47 ± 40.69; 33 ± 19.05), respectively. However, egg yolk had the best feed conversion ratio (0.20 ± 0.05) compared to the commercial pellets (0.22 ± 0.04) and Artemia (0.26 ± 0.07). Critical water quality parameters were maintained within acceptable survival ranges for C. rendalli across all treatments. These findings highlight the importance of dietary protein content in optimizing the growth and survival of C. rendalli under intensive culture conditions and provide insights for effective feeding strategies. However, commercial pellets are expensive and inaccessible to small-scale fish farmers. As an alternative, egg yolk emerged as a viable and affordable feed option, promoting fish growth and supporting the establishment of small-scale farming practices in the region.

Aquaculture Journal doi: 10.3390/aquacj4030012

Authors: Anacleto M. Argayosa Mary Nia M. Santos Vina B. Argayosa Rolando V. Pakingking William Buhian Mizpah L. Salvador Rosaneth E. Teh

Motile aeromonad septicemia (MAS), caused by the Aeromonas species, has been a serious problem in fish health management, particularly in Nile tilapia (Oreochromis niloticus). This study characterized an Aeromonas species isolated from farmed tilapia fingerlings in Binangonan, Rizal, Philippines, and tested for its pathogenicity in tank trials. The isolate, designated as Aeromonas veronii DFR01 (Diseased Fish Rizal), was identified based on 16S rRNA phylogenetic analysis, 16S rRNA homology, and MALDI-TOF mass spectrometry. Its biochemical profile was generated from API and Biolog Gen III systems. A median lethal dose of A. veronii DFR01 was determined to be 107 CFU/mL in tank trials and was utilized as a whole-cell inactivated antigen for oral vaccine development. The immunized tilapia fingerlings produced elevated levels of immunoglobulin M (IgM) in the blood as determined by an enzyme-linked immunosorbent assay (ELISA). There was a significant increase in IgM levels 14 days post-vaccination. A quantitative polymerase chain reaction (qPCR) showed increasing levels of IgM gene expression after vaccination until 38 days of culture. Vaccinated fish showed 25–35% cumulative mortality after the challenge, while non-vaccinated-challenged fish showed 75% mortality. The findings of this research suggest that the fish oral vaccine may prove beneficial for farmed tilapia populations. The vaccine elicited improved immune responses in the fish and resulted in higher survival rates.

Aquaculture Journal doi: 10.3390/aquacj4030011

Authors: Anderson Paixão Hungria Monique Damasceno Pinto Antônia Rafaela Gonçalves Macedo Osnan Lennon Lameira Silva Regiara Croelhas Modesto Lenilton Alex de Araujo Oliveira Lian Valente Brandão Fabricio Nilo Lima da Silva

Despite the huge potential of aquaculture in the Amazon, several producers have abandoned the activity due to a lack of assistance, technology, and innovation. Thus, the objective of this study was to identify factors that have contributed to the withdrawal of aquaculturists from the municipality of ‘Vigia de Nazaré’, state of Pará (Northern Region of Brazil). This case study took place in 2022 through a quanti-qualitative survey, applying structured questionnaires to former aquaculturists. A total of 30 fish farms were investigated, with 11 of them being abandoned. They are distributed across 10 rural communities that have developed fish farming, with ‘Vila de Itapuá’ (18.2%) being the most representative. When active, fish farming was practiced by men (100%) aged between 51 to 60 years (54.5%) with an incomplete primary education (100%), who carried out the activity for an average of 5 years (81.8%), quitting fish farming between the years 2019 and 2020 (72.7%). All former aquaculturists owned small properties, with excavated ponds in an extensive system and used family labor. The absence of technical assistance and the high cost of feed were pointed out as the main problems in the production chain. It is worth noting that the monoculture of Tambaqui (Colossoma macropomum) accounted for 63.6% of the species produced in rural communities. In conclusion, former aquaculturists express the desire to return to fish farming due to its socio-economic importance. For this, government actions supporting technical assistance and advanced studies in fish nutrition by educational, research, and extension institutions are necessary.

Aquaculture Journal doi: 10.3390/aquacj4030010

Authors: Jailson Novodworski Émerson José Alves Matos Rafaela Mocochinski Gonçalves Robie Allan Bombardelli Fábio Meurer

This study aimed to determine the protein requirements of the fattening phase for Nile tilapia (Oreochromis niloticus) fed fish meal-free diets. A total of 75 Nile tilapia were maintained in a water recirculation system, and five isoenergetic diets were formulated with increasing protein levels encompassing three repetitions each. The findings revealed that protein levels significantly affected (p < 0.05) certain Nile tilapia performance, yield, and composition parameters. The determined parameter values clearly indicated that Nile tilapia can be fed fish meal-free soybean meal and corn-based diets. Furthermore, the metabolic plasticity of this species concerning dietary protein concentrations was also demonstrated, with adequate performance results achieved in treatments containing from 267 to 294 g/kg digestible protein (DP), or 298 to 327 g/kg crude protein (CP), where the balance between essential and non-essential amino acids and energy resulted in adequate performance correlated to satisfactory feed conversion values and filet yields and composition. A DP concentration of 267 g/kg (298 g/kg CP) is recommended when offering corn and soybean meal-based diets during the Nile tilapia fattening phase to fish weighing between 400 and 700 g.

Aquaculture Journal doi: 10.3390/aquacj4030009

Authors: José Antonio Pérez Agúndez Pascal Raux Loeiza Lancelot Jean-Emmanuel Rougier

Aquaculture development is a challenge for the economic growth of coastal territories and to promote the food security of their populations. Many efforts have been made by international, national, and local public institutions to develop this sector. Despite this political objective, the coastal zones of Europe and the Mediterranean in general are faced with problems that strongly limit this development. This is linked to several factors, including social opposition, which raises the question of the social acceptability of aquaculture development. Beyond understanding the factors that explain the social rejection of this sector or its products, the key question concerns the capacity of private and public institutions to deal with this social opposition in a practical way. Based on fieldwork and a participatory approach, this paper analyzes the constraints of aquaculture development in Monastir Bay, Tunisia, and in particular, those relying on social dimensions. Under this participatory approach, the authors propose a research–action framework allowing the building of bases for engaging stakeholders in a co-construction process of a shared vision of aquaculture development in Monastir, in accordance with the constraints and ambitions expressed by the local communities regarding territorial needs. This paper shows the value of building the transition from an individual or group vision to a collective vision through a participatory approach that is likely to form a consensus, as opposed to an aggregation of individual visions that can lead to social unacceptance. It also argues that involving citizens in the exploration of aquaculture development scenarios adapted to the territory is an essential prerequisite to exploring the conditions that question the social acceptability and its improvement.

Aquaculture Journal doi: 10.3390/aquacj4030008

Authors: Renata Ávila Ozório Rafael Garcia Lopes Felipe do Nascimento Vieira Norha Constanza Bolívar-Ramírez Carlos Yure Barbosa de Oliveira Margherita Anna Antonia Maria Barracco Marco Shizuo Owatari Debora Machado Fracalossi Roberto Bianchini Derner

Sulfated polysaccharides (SPs), especially those with immunostimulant effects on shrimp and fish, are bioactive compounds with potential use in aquaculture. In this study, Pacific white shrimp (Penaeus vannamei) were fed diets containing 0%, 0.5%, 1.0%, 1.5%, or 2.0% crude extracts from the microalga Porphyridium cruentum for 30 days. After dietary supplementation, the shrimp were exposed to Vibrio alginolyticus, allowing the assessment of phenoloxidase activity (PO) and total hemocyte count (THC) pre- and post-challenge, as well as shrimp survival rates. Shrimp that received the 1.0% treatment had greater survival (90%) at 48 h post-challenge, while the 0% and 2.0% treatments had survival rates close to 63% in the same period. Furthermore, at 48 h post-challenge, THC was significantly greater (p < 0.05) in the shrimp that received crude extract supplementation compared to that in shrimp of the control group (0%). PO showed a proportional increase according to crude extract inclusion levels. Such dose-dependency in response to PO increases became significantly greater (p < 0.05) in the 2.0% treatment group compared to that in the 0% treatment group in the pre-challenge period and that in the 0% and 0.5% treatment groups in the post-challenge period. These results showed that crude extracts from P. cruentum could be considered immunostimulants by increasing the resistance of P. vannamei exposed to V. alginolyticus, potentially representing a major breakthrough for marine shrimp farming.

Aquaculture Journal doi: 10.3390/aquacj4030007

Authors: João Rui Tanoeiro Gustavo W. Fehrenbach Patrick Murray Rui Pedrosa Yuanyuan Chen

This study investigated the adaptability of Dunaliella salina to different salinity levels, with an emphasis on growth, pigment concentration, and desalination potential. It was found that among the 21 salinity levels, Salinity 75 produced consistently favorable results in cell count (13.08 × 103 ± 1.41 × 103 cells/mL), dry biomass (2.46 ± 0.06 g/L), pigment content (chlorophyll a = 97,500,000 ± 100,000 pg/L, chlorophyll b = 123,600,000 ± 300,000 pg/L), and desalination (9.32 ± 0.47 reduction). Therefore, Salinity 75 was selected for the final trial (scale-up), which revealed unanticipatedly high cell counts (58.96 × 103 ± 535.22 cells/mL), with the dry biomass weight being statistically different (higher) than expected (4.21 ± 0.02 g/L) (p < 0.0001), most likely due to the high cell count and energy reserve storage for high-salinity adaption in the form of bio-compounds. Pigment growth continued (chlorophyll a = 95,400,000 ± 2,200,000 pg/L, chlorophyll b = 128,100,000 ± 5,100,000 pg/L), indicating pigment production under salt stress. Notably, desalination did not occur in this stage, possibly due to the necessity for a bigger initial inoculate, prolonged exposure or bioaccumulation becoming the prevailing mechanism over desalination. Nevertheless, the trial highlights D. salina’s strong adaptation to various salinity levels. This suggests a promising future in halophyte research, particularly in understanding the mechanisms that prevent salt accumulation in cells and how to overcome this barrier. Additionally, these results suggest that microalgae could be a viable resource in saline-rich environments unsuitable for conventional agriculture, promoting industrial adaptation to adverse conditions.

Aquaculture Journal doi: 10.3390/aquacj4020006

Authors: Eirini Schoina Laetitia Marchand Agata Zykwinska Corinne Sinquin Françoise Leroi Christine Delbarre-Ladrat George-John E. Nychas

Tenacibaculum discolor develops biofilm in marine aquaculture production tanks and is identified as one of the causative agents of tenacibaculosis, a bacterial disease that causes significant losses in marine aquaculture production. In this study, the biofilm characteristics of T. discolor strain FMCC B487 were evaluated. Cell growth and biofilm formation and development were studied in miniaturized assays to assess the effect of different levels of environmental factors temperature and salinity, as well as the presence of monosaccharides potentially found in aquaculture hatcheries. The ability of the strain to grow and develop strong biofilms in ambient to high temperatures and at salinities above 20 g/L was shown. Mannose was the monosaccharide with the most prominent impact on the T. discolor strain FMCC B487 biofilm. The composition of planktonic cell extract, biofilm extracts, and extracellular polymeric substances (EPS) produced by T. discolor strain FMCC B487 were investigated by means of colorimetric and fluorometric assays as well as analyses by electrophoresis, gas chromatography, and high-performance size-exclusion chromatography coupled with a multiangle light scattering detector, revealing the dominance of proteins and lipids and the absence of high-molecular-weight polysaccharides. This information may serve as a basis for considering anti-biofilm strategies against the pathogen T. discolor.

Aquaculture Journal doi: 10.3390/aquacj4020005

Authors: Lucia Tudini Andrea Forgione

The Italian shellfish industry mainly comprises clams, mussels, and oysters. While clam production thrives and Italy leads Europe, mussel farming faces economic challenges. Oyster production is relatively new and holds potential. Sustainable development is crucial for meeting growing seafood demand while ensuring resource conservation and food safety. This paper, part of the VALUE-SHELL project funded by the Italian Ministry of Agriculture, Food Sovereignty and Forests (MASAF) as part of support activities for the National Strategic Plan of Aquaculture, combines desk research on industry structure and public interventions using a collaborative approach involving stakeholder interviews and focus groups with producers and local entities to assess the sector’s most compelling needs. The collaborative process highlighted key challenges across the following four sustainability pillars: environmental (global warming, predator control, and pollution mitigation are critical concerns for ecosystem balance); economic (increased production costs and limited diversification opportunities affect profitability); social (fear of generational decline due to limited training and education opportunities poses a threat to the industry’s future); and institutional (lack of a dedicated aquaculture law and fragmented governance hinder long-term planning). The project identifies policy bottlenecks hindering the sector’s potential, caused by not fully addressing producer needs. Sustainable development strategies are essential for addressing these challenges and ensuring the Italian shellfish industry’s future.

Aquaculture Journal doi: 10.3390/aquacj4020004

Authors: Ignacio Eduardo Martín-Montero Juan Manuel Martínez-Vázquez Inmaculada Rasines Perez Miguel Torres Juan Antonio Martos-Sitcha Felipe Aguado-Giménez

Chelon labrosus represents a promising species for current aquaculture to lean towards a more sustainable model. The control of reproduction in captivity is essential to develop the industrial production of new species. This work adds to the knowledge of the reproductive aspects of males and females of this species. We aim to (1) develop a methodology for sex identification of reproductive and prereproductive specimens of the studied species based on the plasma levels of steroid hormones—estradiol (E2) and 11-ketotestosterone (11-KT); (2) determine the maturity evolution of the females throughout the spawning season by gonadal biopsy; and (3) describe sperm quality throughout the breeding season (volume, motility, density). The results show that an 11-KT/E2 ratio > 0.4 is 100% effective in distinguishing males from females, provided that individuals present a size greater than that of first sexual maturity. A double trend was observed in the development of oocytes, with an increase in the initial diameter until the middle of the spawning season, followed by a divergence of the group, with some females continuing the maturation process and others going into regression. Sperm data show stable quality at the beginning and in the middle of the spawning season and a significant loss of quality at the end of the reproductive period. The present study also shows that, between the beginning and the middle of the reproductive season, males of this species can recover sperm volume removed by stripping.

Aquaculture Journal doi: 10.3390/aquacj4020003

Authors: Zhixuan Loh Ting Wei Lim Shanshan Wu Howland Sunita Awate Laurent Renia Jinmiao Chen Ee Chee Ren

The study aims to characterize the immune cell landscape in convalescent Asian seabass (Lates calcarifer) blood samples after exposure to scale-drop disease virus (SDDV). Traditional immunophenotyping approaches used in human and mouse studies are impractical for non-model organisms like the Asian seabass due to the lack of specific antibody-based reagents. To overcome this challenge, 10x Genomics single-cell RNA sequencing was employed. The analysis of blood samples revealed 24 distinct leukocyte clusters, with elevated proportions of B cells, granulocytes, and T cells in the convalescent group compared to the uninfected group. While distinguishing granulocyte and macrophage subsets was challenging, the analysis of differential gene expression in the macrophage population indicated that the upregulated genes were linked to inflammatory processes. Specific T cell clusters showed notable expressions of cd4-1, cd8a, perforin-1 and il-2rβ, suggesting the presence of CD4+ T helper (Th), CD8+ cytotoxic T (Tc) cells, immature T cells, and naive T cells. Attempts to categorize CD4+ T cells into Th subtypes lacked clear distinctions, while CD8+ T cells exhibited three clusters, predominantly Tc1 cells. Furthermore, comparisons between convalescent and uninfected groups revealed increased percentages of activated and antibody-secreting B cells in the convalescent group. This single-cell analysis provides vital insights into the immune cell dynamics in convalescent and uninfected Asian seabass, providing valuable information on potential immune responses to SDDV infection.

Aquaculture Journal doi: 10.3390/aquacj4010002

Authors: Nicole McDonald Kristen Lovric Amy Cosby

The digitisation of the agriculture industry provides an opportune context for accelerating sustainable food production. Aquaculture is among the fastest-growing agriculture sectors and is well placed to help address food supply shortages, directly contributing to the achievement of UN Sustainable Development Goal 2. However, the sector currently has inadequate digital capability and enabling conditions to thrive. Social cognitive career theory asserts that career choices and persistence are directly influenced by a person’s thoughts, including their self-efficacy; therefore, the upskilling and reskilling of labour is required to build confidence in their digital capabilities and reduce turnover intentions. Consequently, this study sought to identify the key skills and needs for this workforce to transition to digitally driven ways of working. The results indicated that a range of skills and abilities that enable people to improve their digital capabilities were required. The findings are presented and discussed.

Aquaculture Journal doi: 10.3390/aquacj4010001

Authors: Dariano Krummenauer André Freitas da Silva Missileny Xavier Geraldo Kipper Foes Luís H. Poersch Alessandro Cardozo Wilson Wasielesky

Shrimp farming in the Biofloc Technology System (BFT) is already considered an alternative to the traditional culture. The bioflocs maintain the water quality and can be used as a food supplement for shrimp. The Pacific white shrimp Litopenaeus vannamei forms the basis for most of the production in BFT. However, its culture is limited by the low temperatures. Thus, the BFT culture potential of native species, such as the pink shrimp Farfantepenaeus brasiliensis, should be considered. The present study aimed to compare the cultures of F. brasiliensis and L. vannamei in the grow-out phase in the BFT system. The experiment comprised two treatments: (FB), grown out of F. brasiliensis, and (LV), grown out of L. vannamei. The study lasted 70 days and was conducted at the Marine Station of Aquaculture at the Federal University of Rio Grande, Rio Grande do Sul State, Brazil. The stocking density was 100 shrimp/m² for both species. The shrimp were fed twice a day with commercial food. The physicochemical parameters of the water were monitored throughout the experimental period. The results showed that all physicochemical parameters of the water remained within the tolerated limits for both species. However, during the growth phase in the BFT, it was observed that the L. vannamei shrimp showed a better zootechnical performance than F. brasiliensis. The results indicate that L. vannamei has a higher capacity to catch bioflocs as supplementary food, demonstrating a better response of that species to the BFT system in the grow-out phase compared to F. brasiliensis.

Aquaculture Journal doi: 10.3390/aquacj3040018

Authors: Jesús G. Arellano-Carrasco Rafael Martínez-García Alberto Asiain-Hoyos Juan L. Reta-Mendiola Pablo Díaz-Rivera Susana A. Frías-Gómez Talhia Martínez-Burguete Gloria Gertrudys Asencio-Alcudia Luis Daniel Jiménez-Martínez Rocio Guerrero-Zarate Cesar A. Sepúlveda-Quiroz Carlos A. Álvarez-González

We determined the effects of sodium propionate (SP) added to the diets of Atractosteus tropicus juveniles with respect to the growth, survival, digestive enzyme activity, and expression of genes that are associated with the immune system. Five treatments (0, 0.5, 1.0, 1.5, and 2.0%) were evaluated in triplicate on 180 fish (3.65 ± 0.12 g) distributed among 15 (70 L) tanks. The juveniles were fed five times a day with 5% feed in relation to the biomass of the organism. The treatment with 0.5% SP showed a final weight value of 25.7 ± 4.5 g, absolute weight of gain (AWG) of 21.93 ± 4.39 g, and specific growth rate (SGR) of 3.1 ± 0.26. Treatments with 1.5 and 2.0% SP showed the highest survival (91.6%). The control group (0%) showed a greater activity of lipases. There was a tendency that the highest activity of alkaline proteases and chymotrypsin occurred in the 0 and 0.5% treatments. The maximum relative expression of the genes ocln, muc2, and nod2 occurred in the 1.5% treatment. The inclusion of SP in the diet of A. tropicus juveniles could benefit the activity of some digestive enzymes as well as the expression of genes related to the function of the intestinal barrier, therefore benefitting the survival of the organisms.

Aquaculture Journal doi: 10.3390/aquacj3040017

Authors: Gustavo Alberto Arbeláez-Rojas Maria da Graça Gama Melão

Freshwater fish larviculture techniques still have deficiencies in cultivation and feeding. In this study, we evaluated experimentally different cultivation and feeding systems in the Brycon amazonicus (matrinxã) larviculture. Seven treatments with different live foods were used: T1 = a semi-intensive mesocosm system with green water; T2 = a clear water system containing Artemia sp. as food; T3 = a clear water system containing Dendrocephalus brasiliensis as food; T4 = a clear water system containing a combination of Artemia sp. and D. brasiliensis as food (a proportion of 1:1); T5, T6 and T7 were the same as T2, T3 and T4, respectively, but with a swimming exercise system. During the experiment, the water quality parameters were measured and maintained suitably for the cultures. The highest values of final weight (42.97 ± 2.58 mg) and specific growth rate (31.77 ± 0.60%) were observed in T5 (p < 0.05). Regarding the nutritional composition, the larvae of B. amazonicus that were fed nauplii of D. brasiliensis had a better profile of amino acids and essential fatty acids than those fed other live foods. Therefore, nauplii of D. brasiliensis can be used as an adequately nutritional food for larvae of B. amazonicus.

Aquaculture Journal doi: 10.3390/aquacj3030016

Authors: María de Jesús Contreras-García Wilfrido Miguel Contreras-Sánchez Manuel Mendoza-Carranza Alejandro Mcdonal-Vera Leonardo Cruz-Rosado

The common snook (Centropomus undecimalis) is a protandric hermaphrodite fish that undergoes a sex change during its life cycle. In nature, common snook females develop directly from males shortly after spawning. However, the factors triggering this process remain unknown. This knowledge gap poses challenges for managing the species in captivity. To address this, we conducted a study on sex change induction in three-year-old males using estradiol and evaluated the potential effects of photoperiod manipulation on early maturation. Four treatment groups were employed: (1) fish with estradiol + natural photoperiod; (2) fish without estradiol + natural photoperiod; (3) fish without estradiol + controlled photoperiod; and (4) fish with estradiol + controlled photoperiod. The effectiveness of these treatments was assessed through histological procedures, which allowed for the examination of the fishes’ gonads. Furthermore, the concentration of alkali labile phosphorus in fish plasma was measured and correlated with the histological results. Our findings revealed that administering 2 mg/kg estradiol implants resulted in a remarkable 100% female population within the estradiol-treated groups. No significant effect on fish maturation was observed due to the manipulated photoperiod conditions. This protocol offers improved management strategies for captive broodstock. Firstly, the concentration of estradiol used in this study proved sufficient to induce sex change in this hermaphroditic species, enabling the production of viable females at an early age and smaller size and facilitating easier broodstock manipulation. Secondly, the implementation of the alkali labile phosphorus technique allows for sex identification without the need to sacrifice the fish. In conclusion, our study provides valuable insights into sex change induction and photoperiod manipulation in common snook. The findings contribute to enhanced management practices for captive broodstock. However, further research is needed to explore the underlying mechanisms triggering sex change and to optimize protocols for long-term maintenance and successful reproduction in captivity.

Aquaculture Journal doi: 10.3390/aquacj3030015

Authors: Olanrewaju Oladokun

One fifth of the world’s population and critical infrastructures are close to the coast and regions of high-risk sea level rise elevation. The last decades have been characterized by increasing extreme events, including storm surges, flooding, coastal erosion, enhanced coastal vulnerability with associated livelihood, and economic losses. Nature-based engineering solutions are being adopted as sustainable solutions for helping existing technologies live their design life and providing climate change adaptation and resilience for coastal and riverine communities. This paper involves the investigation of nature-based eco-hydraulic soft coastal engineering to cultivate seaweed for coastal protection. In this context, the present study involves an advanced risk evaluation performed by conducting an extreme bore interaction with seaweed as a soft engineering coastal protection measure. The load reduction on the inland structure during extreme flooding conditions, incorporating seaweed, is addressed. The present study indicates that the load on inland structures can be reduced by as much as 14% in extreme flooding conditions in the presence of seaweed with two rows of seaweed, indicating the usage of seaweed as a part of coastal protection over existing site protection infrastructure for improved coastal mitigation.

Aquaculture Journal doi: 10.3390/aquacj3030014

Authors: Md. Shahzad Kuli Khan Krishna R. Salin Amararatne Yakupitiyage Takuji W. Tsusaka Loc Thai Nguyen Mohammad Abdul Momin Siddique

Severe cannibalism can result in a significant loss of productivity during the nursery phase of Asian seabass, Lates calcarifer. The present study aimed to determine the effect of dietary tryptophan on growth, feed utilization, cannibalism, survival, and muscle proximate composition of Asian seabass juveniles (initial size, 2.77 ± 0.04 cm in length and 0.29 ± 0.01 g in weight) in a recirculating aquaculture system (RAS) at different stocking densities. The tryptophan levels were set at 0.41% (control diet, standard dosage for normal growth and survival of Asian seabass), 1.00% (Diet 1), and 1.50% (Diet 2), while the stocking densities were set at 0.5 ind./L and 1.5 ind./L. The results indicated that dietary supplementation with L-tryptophan (TRP) and fish stocking density had a significant effect on fish growth parameters, feed utilization, cannibalism, survival, and muscle lipid content (p < 0.05) over the 45-day trial. The maximum length, weight, WG, and SGR were 11.64 ± 0.35 cm, 22.93 ± 2.67 g, 22.64 ± 2.67 g, and 9.63 ± 0.27%, respectively, in the fish fed Diet 2, and 11.35 ± 0.22 cm, 24.38 ± 1.28 g, 24.09 ± 1.28 g, and 9.82 ± 0.11% at a 1.5 ind./L stocking density. The lower FCR (0.81 ± 0.04) and higher PER (2.98 ± 0.16) ensured better utilization of Diet 1 than the other diets. Moreover, significant interaction effects between diet and stocking density were observed in total yield, cannibalism, and survival of the Asian seabass. Significantly higher survival rates of 76.11 ± 3.90% in the Diet 1 group and 76.28 ± 2.88% in 0.5 ind./L stocking density were obtained, which is promising. The study concludes that dietary supplementation with 1.00% TRP was effective in reducing cannibalism and increasing the survival of the Asian seabass nursery reared in RAS at a lower stocking density (i.e., 0.5 ind./L), whereas 1.50% supplemental TRP at a higher stocking density (i.e., 1.5 ind./L) significantly increased the cannibalism and growth, which in turn reduced the survival rate.

Aquaculture Journal doi: 10.3390/aquacj3020013

Authors: Nathan J. Thomas Kam W. Tang Christopher J. Coates

Symsagittifera roscoffensis is an intertidal Acoel flatworm that forms a symbiotic relationship with the alga Tetraselmis convolutae. Members of the genus Tetraselmis are known to have a high nutritional value and have been widely used to enrich intermediate prey for fish within the aquaculture industry; therefore, S. roscoffensis could be a good candidate as a trophic shortcut to deliver algal nutrition to fish. In this study, we investigated the likelihood of five ornamental tropical freshwater and six ornamental marine fishes to consume this worm, either as live feed or in freeze-dried form. We also tested the ability of S. roscoffensis to form a symbiotic relationship with alternative algal species, analysing the nutritional profile of S. roscoffensis when grown in different media. All the experimental fish consumed live worms to some degree, with the exception of one species (Meiacanthus grammistes); the response time to the worms ranged from 1.1–68.6 s for freshwater ornamental species to 1–24 s for marine ornamental species, and in most cases, this was comparable to or shorter than their response time to the reference diet Artemia. The fishes showed no negative effects after consuming the worms. We obtained similar results with freeze-dried worms in terms of the number of worms eaten, response time, and feeding time. Symsagittifera roscoffensis was able to form a symbiotic relationship with all the tested algal species of the genus Tetraselmis, but not with members of other genera. Worms grown in nutrient media (f/2 and f/4) had significantly higher contents of protein, pigments, and total and polyunsaturated fatty acids, including eicosapentaenoic acid (20:5n − 3) and α-linolenic acid (18:3n − 3), than those grown in seawater. These results show that S. roscoffensis was acceptable to many ornamental fish species, delivering key algal ingredients that are beneficial to fish health; hence, it is a promising alternative to conventional fish feeds for the ornamental pet trade.

Aquaculture Journal doi: 10.3390/aquacj3020012

Authors: Salifu Ibrahim Zhenxiao Zhong Xuan Lan Jinping Luo Qiongying Tang Zhenglong Xia Shaokui Yi Guoliang Yang

The giant freshwater prawn (GFP), Macrobrachium rosenbergii, is one of the largest palaemonids in the world, found in tropical marine, estuarine, and freshwaters, and is among the most commercially cultured crustaceans. According to research, mature males usually develop differences in cheliped morphology, growth characteristics, and agonistic behavior. The identification of such morphotypes is critical for effectively managing and handling prawns. The present study aimed to describe the GFP male population structure in culture ponds (the Yangtze River delta, China). Sixteen morphometric traits and four weight data were measured for each four male morphotype. Principal component and clustering analyses were conducted to investigate the morphological variation among the four morphotypes. The study of relative growth was also employed to estimate the growth patterns of body structures (dependent variables) in relation to the carapace length (independent variable). A detailed description of the cheliped’s macroscopic characteristics that differed among morphotypes was provided, which corroborated with previous studies of the species. The four morphotypes were statistically different regarding the cheliped morphology, size, and morphometric relationships and equations, indicating a considerable variation in growth among the four male morphotypes. The present results contribute to a clear understanding of the population biology of GFP and support future management and broodstock selection activities.

Aquaculture Journal doi: 10.3390/aquacj3020011

Authors: Inmaculada Rasines Ignacio Eduardo Martín Felipe Aguado-Giménez

The polychaete Hediste diversicolor is a suitable species for industrial aquaculture; however, cost-effective culture techniques need to be developed for its intensive production. The aim of this study is to evaluate the effects of worm density and substrate height and their interaction, as well as feeding frequency, on the rearing performance of H. diversicolor. Two trials were conducted. In trial 1, the effects of two substrate heights—6 and 12 cm—and two rearing densities—1000 and 4000 individuals m−2—were assessed in terms of worm growth and biomass production. Worm initial wet weight was 48 mg, and specimens were fed with commercial fish feed during a 70-day assay. The results show no interaction between rearing density and substrate height, and confirm density as a key factor in growth; however, a density of 4000 individuals m−2 results in a significant increase in production (final biomass three times higher for the highest rearing density) without affecting survival. In trial 2, the effect of three levels of feeding frequency—seven days a week; three times a week; and once a week—on growth in individuals of three weight classes—small (25–50 mg); medium (100–150 mg); large (250–350 mg)—was evaluated in a 15-day growing assay. Feeding frequency showed a major influence on the smallest size class, with the best growth indicators obtained at the highest feeding frequency. This study shows that Hediste diversicolor can be reared at a high stocking density to obtain a higher biomass production, and that feeding frequency must be considered as an important factor and adapted to the culture phase.

Aquaculture Journal doi: 10.3390/aquacj3020010

Authors: Franz Lahnsteiner Elias Lahnsteiner Anna Duenser

First feeding of many fish larvae depends on live feed. A comparative investigation on the effectiveness of different types of live feed is not available to our knowledge. Hence, we conducted a study to examine the effect of different types and combinations of live feed on the performance (survival rate, total length, body width, body mass, malformation rate) of pikeperch, Sander lucioperca, larvae. From day 0 (onset of exogenous feeding) to day 10, the saltwater rotifer Brachionus plicatilis, the freshwater rotifer Brachionus calyciflorus, the ciliate Paramecium bursaria, copepods (nauplii and copepodites) from a lake population, and Artemia nauplii were tested. Feeding with B. plicatilis, B. calyciflorus, and P. bursaria resulted in high survival rates of 80% and a homogenous and significant growth (increase in total length of 50% and in body width of 20%). As follow-up feed, copepod nauplii and Artemia nauplii were tested from day 11 to day 20. Copepod nauplii were superior to Artemia nauplii, as larvae fed with copepods showed higher survival rates (67–70% versus 38–47%) and a more homogeneous growth. A switch from seawater live feed to freshwater live feed or vice versa resulted in decreased survival rates. Therefore, a feeding regime consisting of B. calyciflorus or P. bursaria followed by copepods is considered optimal as first feed of pikeperch. The malformation rate was not affected by the tested feeding regimes. To investigate the wider applicability and transferability of these findings, complementary investigations were performed on burbot, Lota lota, and the freshwater whitefish Coregonus atterensis. The feeding regimes used for S. lucioperca larvae were also suitable for Lota lota. Moreover, L. lota could be fed with lake copepods from the onset of exogenous feeding. For C. atterensis, initial feeding with B. plicatilis, B. calyciflorus, or P. bursaria had no positive effects. Feeding with copepods from the onset of exogenous feeding was optimal considering survival rate and growth. Therefore, optimal first feeding regimes are very species specific and should be established for each new species.

Aquaculture Journal doi: 10.3390/aquacj3020009

Authors: Likentso Sylvia Shuping Izanne Susan Human Jan Frederik Rykers Lues Arnelia Natalie Paulse

The disposal of treated and untreated sewage near shellfish harvesting areas is a global concern. Discharged sewage may be contaminated with enteric viruses present in human faeces. Bivalve molluscs, in turn, act as vectors for enteric viruses through bioaccumulation and retention of these viruses during the filter-feeding process, resulting in outbreaks of infections due to the consumption of contaminated shellfish. This review was conducted using peer-reviewed articles published from 2012 until September 2022, obtained from online databases such as Google Scholar, Scopus, and Science Direct, highlighting the challenges that the shellfish industry is faced with concerning pollutants ending up in the shellfish production areas. Developed countries have made some advancements by upgrading sewage infrastructures, which reduced viral loads in sewage. However, it is difficult to measure the significance of these improvements, as there are no regulations in place which stipulate the permissible limits for viruses. In most developing countries, including South Africa, there is a lack of effective management plans for virus monitoring in shellfish harvesting areas. The findings of this study indicated a need for extensive research on the origin of viruses, their interactions with other organisms within the marine ecosystem, the quantification of viruses within the Saldanha Bay harbour, and the development of virus management plans which currently are non-existent.

Aquaculture Journal doi: 10.3390/aquacj3020008

Authors: Mohammad Abu Baker Siddique Balaram Mahalder Mohammad Mahfujul Haque Abul Bashar Md. Mahmudul Hasan Mobin Hossain Shohan Md. Mahamudun Naby Talukdar Jatish Chandra Biswas A. K. Shakur Ahammad

Embryonic and larval development of tilapia (Oreochromis niloticus) is very vulnerable to climate change. This study was conducted for an assessment of the embryonic and larval development of Nile tilapia in traditional hatchery and re-circulatory thermostatic systems. Daily changes in embryonic and larval development were measured through microscopic observation and image analysis in the laboratory. Climatic data and water quality parameters were measured every day using appropriate devices. Water temperature was varied with room temperature at the traditional hatchery system while it was maintained at 28.50 °C in the re-circulatory thermostatic system. A total of 200 unhatched eggs were stocked in every three trays of both systems. The egg diameters of the gastrula, segmentation, and pharyngula stages were measured at higher (2261.47 ± 81.66 µm, 2646.24 ± 17.98 µm, and 2710.90 ± 16.60 µm) in the re-circulatory thermostatic system than in the traditional hatchery system (2261.07 ± 81.52 µm, 2645.47 ± 18.24 µm, and 2710.01 ± 16.45 µm), respectively. For both systems, egg colors, egg size, black pigments, germinal ring, eye shape, tail, and heartbeat were determined through microscopic observation. Higher hatching and survival rates were found under the re-circulatory thermostatic system (95% and 97%) than under the traditional hatchery system (85% and 81%). About 6 h less hatching time was required under the re-circulatory thermostatic system than under the traditional system. At the end of 30 DAH (Days After Hatching), larval length and weight under the re-circulatory thermostatic system were found to be higher (15.736 ± 0.424 mm and 0.0528 ± 0.004 g) than under the traditional hatchery system (15.518 ± 0.415 mm and 0.050 ± 0.004 g), respectively. Larval growth patterns for both systems were found to have an exponential trend. PCA analysis revealed that two components were identified, one primarily associated with morphometric characteristics and the other with climatic and water quality parameters. These components showed that there were several interrelationships between the morphometric changes and the climatic and water quality parameters. The characteristic changes of larval development under the re-circulatory thermostatic system and the traditional hatchery system were found to be remarkably similar except for some deformities denoted under the traditional hatchery system. The changes of yolk sac, body pigmentation, dorsal and caudal fin shape, eye size, and head length and width were determined from 1 DAH to 30 DAH. After absorbing the yolk sac, ready-made feed was provided. The water temperature was varied from 30.50 °C to 35.50 °C in the traditional hatchery system. The highest air temperature and humidity were 33.87 °C and 69.94% while the lowest were 29.63 °C and 45.62%, respectively, in the traditional hatchery system. There has been no such comprehensive comparative study on hatchery production in Bangladesh, and therefore, further research might be carried out on broader aspects. This research would be highly beneficial for improving seed production at the tilapia fish hatchery level in the country.

Aquaculture Journal doi: 10.3390/aquacj3010007

Authors: Ram C. Bhujel Anusha D. Perera Nemanja Todorović Jog Raj Rui A. Gonçalves Marko Vasiljević

Mycotoxins have become a serious issue in the animal feed industry and have also affected the aquaculture industry. Mycotoxins can create serious health problems in aquatic and terrestrial animals, and their presence in agricultural products may result in significant economic losses. To reduce the impact of mycotoxins on Nile tilapia fry, two commercially available products—Organically Modified Clinoptilolite (OMC) and multi-component mycotoxin detoxifying agent (MMDA)—were used in this study. Six diets as treatments (T1 = Control (C); T2 = Control + OMC 2 g/kg (OMC); T3 = Control + MMDA 2 g/kg (MMDA); T4 = AFB1 0.5 mg/kg (AF); T5 = AFB1 0.5 mg/kg + 2 g/kg OMC (AFOMC); T6 = AFB1 0.5 mg/kg + MMDA 2 g/kg (AFMMDA)) with similar crude protein levels (35.75 ± 0.35%) were formulated and fed to Nile tilapia fry (1.97 ± 0.1 g) for a period of 84 days. These fish were housed in 18 aquaria (100 L) at a density of 50 fish/aquarium. The results from this study showed that MMDA significantly (p < 0.05) improved the survival of fish by 16% as compared to the control group. Nevertheless, growth parameters were not affected among the treatments. These results also indicated that protein intake was significantly higher in the control and OMC diet (T2) compared to aflatoxin B1-fed tilapia. The protein efficiency ratio (PER) was significantly higher in the AFMMDA as compared to the control and MMDA. A 14-day bacterial challenge test with Aeromonas hydrophila demonstrated that diets containing MMDA or OMC improved survival when AFB1 was present in the diet. Therefore, the supplementation of feed with MMDA or OMC is recommended to ameliorate the negative effects of AFB1 in Nile Tilapia feeds.

Aquaculture Journal doi: 10.3390/aquacj3010006

Authors: Eduardo De La Cruz-Marín Rafael Martínez-García Jenny F. López-Hernández Otilio Méndez-Marín Susana C. De la Rosa-García Emyr S. Peña-Marín Dariel Tovar-Ramírez Cesar A. Sepúlveda-Quiroz Graciela M. Pérez-Jiménez Luis D. Jiménez-Martínez Gloria G. Asencio-Alcudia Carlos A. Álvarez-González

The effect of adding inulin to balanced diets for tropical gar (Atractosteus tropicus) larvae on growth, survival, digestive enzyme activity, and antioxidant activity was evaluated. The diets were supplemented with 0.5, 1.0, 1.5, 2.0, and 2.5% inulin in addition to a control diet (0% inulin). A total of 1800 larvae of A. tropicus distributed in 18 tanks were used; the larvae were fed five times a day (8:00, 11:00, 13:00, 15:00, and 18:00) with Artemia nauplii from the absorption of the yolk (from 3–7 days after hatching, DAH) up to 10 DAH, which was mixed with the experimental feeds from 8–11 DAH (co-feeding) and exclusively with the balanced diets from 12 DAH to 21 DAH. Larvae fed the control diet (0% inulin) had the highest growth in weight and length, followed by fish fed the 2.5 and 2.0% inulin inclusions. However, survival showed that the fish fed with the inclusion of 2.5% inulin had the highest percentage (34.7%) compared to the rest of the treatments. On the other hand, the highest digestive enzymatic activities (acid and alkaline proteases, amylase, and lipase) were recorded in the larvae fed with 2 and 2.5% inulin. Likewise, catalase (CAT) and superoxide dismutase (SOD) activities were higher in larvae fed the control diet with 0% inulin. Supplementation of 2.0% to 2.5% inulin in the diet is recommended for A. tropicus larvae as it improves survival and digestive enzyme activity during this early stage of life.