Aquac. J., Volume 5, Issue 4 (December 2025) – 11 articles

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. Full article

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. Full article

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. Full article

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. Full article

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). Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article