Search Results (184)

Global marine coastal aquaculture increased by 6.7 million tons in 2024, with whiteleg shrimp (Penaeus vannamei) dominating crustacean production. However, reliance on a single species raises sustainability concerns, particularly in the face of climate change. Diversifying shrimp farming by cultivating native species, such as the European brown shrimp (Crangon crangon), presents an opportunity to develop a sustainable blue bioeconomy in Europe. C. crangon holds significant commercial value, yet overexploitation has led to population declines. Integrated Multi-Trophic Aquaculture (IMTA) offers a viable solution by utilizing fish farm wastewater as a nutrient source, reducing both costs and environmental impact. Research efforts in Germany and other European nations are exploring IMTA’s potential by co-culturing shrimp with species like sea bream, sea bass, and salmon. The physiological adaptability and omnivorous diet of C. crangon further support its viability in aquaculture. However, critical knowledge gaps remain regarding its lipid metabolism, early ontogeny, and reproductive biology—factors essential for optimizing captive breeding. Future interdisciplinary research should refine larval culture techniques and develop sustainable co-culture models. Expanding C. crangon aquaculture aligns with the UN’s Sustainable Development Goals by enhancing food security, ecosystem resilience, and economic stability while reducing Europe’s reliance on seafood imports. Full article

Sea lice have been a persistent pest of the salmon farming industry for more than 50 years. In this study, we aimed to identify if different strains of Atlantic salmon with discrete long-term lice exposure histories had variable resistance to copepodid attachment and/or different attachment-specific transcriptome patterns. We additionally sought to characterize lice distributions on fins, head, and skin and identify if attachment location influenced transcriptomic profiles of lice. Lice counts were correlated with body size and highest on St. John River (SJR; open ocean-run) relative to Grand Lakes Stream (GLS; 200-year restricted ocean-run) or Sebago Lake (CAS; ~11,000 years landlocked) Atlantic salmon. However, lice density was similar between strains. Skin and fins had expectedly different transcriptomic profiles; however, notable differences were not observed between salmon strains. Variance in lice transcriptomes was minimally affected by attachment location even though lice strongly preferred fins relative to head or body. Attached lice did have different transcriptomic profiles on GLS relative to CAS or SJR. This study cumulatively identified a minimal host evolutionary component for sea lice attachment resistance, although lice behavior post-attachment appeared somewhat affected by strain. Non-uniform settlement distributions and tank-specific variability in lice attachment were observed across populations. Full article

Standard blood agar medium with 2% NaCl (BAS) and Marine Agar (MA) are commonly used in bacteriological investigations of winter ulcers in farmed Atlantic salmon (Salmo salar Linnaeus) in Norway and allow easy recovery of Moritella viscosa based on its characteristic viscous colonies and β-hemolytic activity. However, the recent increase in cases of winter ulcers involving Tenacibaculum spp. and the potential emergence of T. maritimum due to rising temperatures highlight the need for improved methods of isolation and identification. Indeed, the recovery of Tenacibaculum spp. from outbreaks of winter ulcers or tenacibaculosis can be challenging. Despite the development of several agar media over the years to overcome this issue, such as Flexibacter maritimus medium (FMM), it remains difficult to differentiate Tenacibaculum species. We evaluated the growth dynamics and phenotypic characteristics of 13 bacterial isolates commonly associated with ulcer outbreaks on five different agar media, including two new formulations: kanamycin-supplemented marine blood agar for the selective isolation of Tenacibaculum spp. (KABAMA) and general blood agar for marine bacteria (BAMA). These new media facilitate the identification of Tenacibaculum spp., including T. maritimum, by distinguishing colonies based on their specific color, shape, and hemolytic activity. Full article

Aquaculture advancement depends on alternative raw materials to reduce reliance on fishmeal (FM) and fish oil (FO) from extractive fisheries. Strategies like restricted feeding reduce costs and improve sustainability by minimizing feed waste and enhancing water quality, while selective breeding boosts growth and adapts fish to innovative diets. However, these measures may affect quality and shelf life. Gilthead seabream selected for high growth or non-selected were fed in 500 L tanks for 300 days until apparent satiety (AS) or with food restrictions (85AS or 65AS) using a control diet with low FM and FO balanced with vegetable ingredients, and an alternative diet (ALT) where FM was substantially replaced with insect, poultry by-product, feather, and porcine blood meals, while FO was completely replaced by microalgae, poultry, and salmon by-product oils. The ALT diet improved EPA + DHA levels, n-3/n-6 ratio, and fillet hardness. The selected fish outperformed the non-selected ones in growth and were more resilient to ALT diet and feeding restrictions. The 85AS feeding strategy optimized fillet quality by preventing lipid accumulation and muscle adaptations, as observed with the other feeding strategies. Combining sustainable feed formulations, genetic selection, and moderate feed restriction enables a viable, long-term strategy for high-quality, environmentally responsible seabream farming. Full article

Melanosis, or melanized focal changes (MFCs), is a significant issue in the Atlantic salmon (Salmo salar) farming industry, causing economic losses due to fillet downgrading. Nevertheless, molecular mechanisms underlying melanosis remain poorly understood, particularly in Chilean aquaculture. This study aimed to characterize transcriptional regulation associated with melanogenesis and inflammation in salmon muscle tissues exhibiting melanosis. Samples were collected from fish at three productive stages, all with MFCs in muscle in common: freshwater at two different origins and accumulated thermal units “ATUs” (300 ATUs post-antibiotic overdose, “Security”; 600 ATUs post-vaccination, “Vaccination”) and seawater harvest (“Harvest”). Gene expression analysis by qPCR targeted melanogenesis-related genes (mitf, tyr, and dct) and immune markers (arg2, inos2, and il-1β). Results revealed significant transcriptional modulation in freshwater samples, including downregulation of mitf, upregulation of dct, and changes in immune-related genes (arg2 and inos2). In contrast, seawater (“Harvest”) samples showed significant upregulation of tyr and dct, but no significant immune gene modulation. These findings indicate distinct molecular responses depending on the MFCs’ development stage, emphasizing early stages as critical points for intervention. Unlike recent studies, which have predominantly focused on samples from the harvest stage, this work uniquely integrates results from both the freshwater phase and the harvest stage. Full article

This study presents numerical simulations of the Aysén tsunami, which occurred on 21 April 2007. The tsunami was triggered by hundreds of landslides caused by a magnitude 6.2 earthquake. With an estimated wave height of 50 m at the northern tip of the Mentirosa Island, the event resulted in 10 fatalities and the destruction of multiple salmon farms along the fjord. We employed the NHWAVE and FUNWAVE-TVD numerical software to conduct a series of simulations using various landslide configurations and two approaches to model landslide motion: a viscous flow and a solid slide governed by Coulomb friction. The numerical results indicate that the solid landslide model without basal friction provides the most accurate representation of the measured in situ run-up heights and generates the largest inundation areas. Furthermore, the simulation results show that the arrival time of the tsunami waves was approximately 600 s. Our findings indicate that the volume of the landslide is the most critical factor in determining tsunami wave heights. Additionally, the Coulomb friction angle is another significant parameter to consider in the modeling process. Full article

Fish red blood cells (RBCs) are nucleated, transcriptionally active, and key players in both gas transport and immune responses. They are the primary targets of Orthoreovirus piscis (PRV), the etiological agent of heart and skeletal muscle inflammation (HSMI), which includes three genotypes (PRV-1, PRV-2, and PRV-3), linked to circulatory disorders in farmed salmon. In Chile, PRV-3 affects the coho salmon (Oncorhynchus kisutch), but host–pathogen interactions remain poorly characterized. This study compared the interactions of PRV-3 in coho salmon and PRV-1 in Atlantic salmon (Salmo salar) using RBC infection models. RBCs were isolated from healthy juvenile salmon (n = 3) inoculated with either PRV-1 (Ct = 18.87) or PRV-3 (Ct = 21.86). Poly I:C (50 µg/mL) was used as a positive control for the antiviral response. Cells were monitored for up to 14 days post-infection (dpi). PRV-3 infection in coho salmon RBCs caused significant metabolic disruption, apoptosis from 7 dpi, and correlated with increasing viral loads. In contrast, PRV-1 infection in Atlantic salmon RBCs showed limited apoptosis and maintained cell viability. Coho salmon RBCs upregulated rig-i, mx, and pkr transcripts, indicating activation of the type I interferon pathway, whereas Atlantic salmon RBCs exhibited a more attenuated response. PRV-3 induced notable morphological changes in coho salmon RBCs, although neither PRV-3 nor PRV-1 caused hemolysis. These findings highlight species-specific differences in RBC responses to PRV infection and provide new insights into the pathogenesis of PRV-3 and PRV-1. Full article

Aquaculture is currently the fastest-growing sector in animal production, with an average annual growth rate of 7.5% since 1970. In Chile, the industry is largely driven by salmonid farming, with Salmo salar (Atlantic salmon) accounting for over 65% of national production. This species has shown the most significant growth within the sector. This growth is achieved by having high-density farming, which results in high levels of stress due to overcrowding and the appearance of pathogens such as the Infectious Salmon Anemia (ISA) virus, Bacterial Kidney Disease (BKD), Caligus sea lice (Caligus rogercresseyi), and Piscirickettsiosis (SRS) caused by Piscirickettsia salmonis, among others. This study evaluated the toxicity of the two most commonly used antibiotics in the salmon industry—oxytetracycline and florfenicol—at four concentrations each, using primary liver cell cultures of Atlantic salmon (Salmo salar). Oxidative stress was assessed through enzymatic activity and gene expression of oxidative markers, including cytochrome P450, catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx). Samples were analyzed at 1, 3, 6, 12, and 48 h post-exposure. These findings reveal time- and dose-dependent oxidative responses in salmon liver cells to OTC and FLO, providing critical insights into the sublethal cellular effects of antibiotics commonly used in aquaculture, which indicates the presence of a high amount of free radicals in the liver cells, indicating toxicity of both antibiotics. Full article

Geothermal water, as a by-product of renewable energy generation, can be appreciated as part of a sustainable Blue Economy in terms of resource effectiveness. This could be part of urban geothermal resource parks in the near future. City aquaculture integrated with urban farms running in a cascading model of energy and material consumption can provide an advanced energy-water-food nexus in densely populated areas, evolving into a refined Nature 4.0 habitat. This case study of the world’s first climate-controlled, closed salmon farm based on geothermal resources presents inclusive, water-sensitive design principles and resilient urban planning, where architecture brings aquatic ecosystems indoors. This is also an example of how to reduce investment risk and integrate geothermal development with sustainable, innovative fish farming based on water circulation systems (RAS) and digital technologies to sustain life-support systems. This greenfield project on Poland’s Baltic coast highlights the potential for geothermal investments, demonstrating that even low-temperature extracted water can serve as both a renewable energy source and a valuable resource. Having operated successfully for over a decade with positive certification, this model of efficient geothermal resource utilization appears to be well-suited for replication and broader implementation. Full article

Sustainably farmed Atlantic salmon could drive global food system solutions by contributing essential nutrients to the human diet while delivering high-quality protein. One of the biggest obstacles to sustainable salmon aquaculture in Chile is the prevalence of piscirickettsiosis disease caused by the Gram-negative bacteria Piscirickettsia salmonis and the excessive amount of antibiotics used to eradicate this disease. Farmed salmon products can be consumed without prior processing and therefore present a substantial risk for the transfer of resistant pathogens to humans. Antibiotics also carry the risk of antibiotic residues and damage to the environment. An alternative to antibiotics is the use of natural antimicrobials without the negative influence on the consumer’s microbiome. Here, we evaluate the potential antimicrobial activity against P. salmonis of the marine microalgae Microchloropsis gaditana. A non-genetically modified M. gaditana was grown with nitrogen deprivation to improve the synthesis of the eicosapentaenoic fatty acid (EPA). A spray-dried M. gaditana concentrate (Mg) was elaborated and given to Atlantic salmon for a period of 49 days, and serum and fillet samples were collected. Our results showed a significant increase in the nutritional quality improving the levels of EPA+ Docosapentaenoic acid (DPA) (23%) and Vitamin D₃ (106%) of the fillets treated with Mg. Fish fed serum were challenged with P. salmonis, and serum antibacterial activity was measured. Sera from fish fed Mg-enriched diets showed a significant increase in antibacterial activity (85.68%) against P. salmonis. Our results indicate that Mg can be used as a viable alternative to address the critical problem of microbial resistance and to assure consumers that farm-raised Atlantic salmon is safe. Full article

Predicting seafood consumption behavior is essential for fishing companies to adjust their production plans and marketing strategies. To achieve accurate predictions, this paper introduces a model for forecasting seafood consumption behavior based on an interpretable machine learning algorithm. Additionally, the Shapley Additive exPlanation (SHAP) model and the Accumulated Local Effects (ALE) plot were integrated to provide a detailed analysis of the factors influencing Shanghai residents’ intentions to purchase salmon. In this study, we constructed nine regression prediction models, including ANN, Decision Tree, GBDT, Random Forest, AdaBoost, XGBoost, LightGBM, CatBoost, and NGBoost, to predict the consumers’ intentions to purchase salmon and to compare their predictive performance. In addition, Bayesian optimization algorithm is used to optimize the hyperparameters of the optimal regression prediction model to improve the model prediction accuracy. Finally, the SHAP model was used to analyze the key factors and interactions affecting the consumers’ willingness to purchase salmon, and the Accumulated Local Effects plot was used to show the specific prediction patterns of different influences on salmon consumption. The results of the study show that salmon farming safety and ease of cooking have significant nonlinear effects on salmon consumption; the BO-CatBoost nonlinear regression prediction model demonstrates superior performance compared to the benchmark model, with the test set exhibiting RMSE, MSE, MAE, R² and TIC values of 0.155, 0.024, 0.097, 0.902, and 0.313, respectively. This study can provide technical support for suppliers in the salmon value chain and help their decision-making to adjust their corporate production plan and marketing activities Full article

Background. The increase in antibiotic resistance in human-impacted environments, such as coastal waters with aquaculture activity, is related to the widespread use of antibiotics, even at sub-lethal concentrations. In Chile, the world’s second largest producer of salmon, aquaculture is considered the main source of antibiotics in coastal waters. In this work, we aimed to characterize the genetic and phenotypic profiles of antibiotic resistance in bacterial communities from salmon farms. Methods. Bacterial metagenomes from an intensive aquaculture zone in southern Chile were sequenced, and the composition, abundance and sequence of antibiotic resistance genes (ARGs) were analyzed using assembled and raw read data. Total DNA from bacterial communities was used as a template to recover floR gene variants, which were tested by heterologous expression and functional characterization of phenicol resistance. Results. Prediction of ARGs in salmon farm metagenomes using more permissive parameters yielded significantly more results than the default Resistance Gene Identifier (RGI) software. ARGs grouped into drug classes showed similar abundance profiles to global ocean bacteria. The floR gene was the most abundant phenicol-resistance gene with the lowest gene counts, showing a conserved sequence although with variations from the reference floR. These differences were recovered by RGI prediction and, in greater depth, by mapping reads to the floR sequence using SNP base-calling. These variants were analyzed by heterologous expression, revealing the co-existence of high- and low-resistance sequences in the environmental bacteria. Conclusions. This study highlights the importance of combining metagenomic and phenotypic approaches to study the genetic variability in and evolution of antibiotic-resistant bacteria associated with salmon farms. Full article

This study explored harmful algal bloom (HAB) risk as a function of exposure, hazard and vulnerability, using Scotland as a case study. Exposure was defined as the fish biomass estimated to be lost from a bloom event, based on the total recorded annual production. Hazard was estimated from literature-reported bloom events. Vulnerability was calculated from records of the number of employees (2020), as an estimate of aquaculture-based employment. The dinoflagellate Karenia mikimotoi was identified as the HAB species with the highest frequency of reported bloom events in Scotland, with variable spatial and temporal reports, but environmental and climatological variables regulating these events are currently unknown. The Shetland Islands region exhibited the highest combined HAB risk, with the highest scores in all three components. Vulnerability was particularly important to overall risk within an island setting, where a larger proportion of the population was dependent on aquaculture. The analysis demonstrated the potential to evaluate the economic and social consequences of HAB events on the aquaculture industry. As fish-killing HABs and fish health impacts are likely under-reported, more transparent reporting of events and related fish health and physiological consequences is recommended for a more quantitative application of this approach. Full article

Acoustic lice treatment (AcuLice) is a newly developed system which uses a composite acoustic sound image with low-frequency sound to remove salmon lice (Lepeophtheirus salmonis) from Atlantic salmon (Salmo salar). The effect of AcuLice treatment on salmon lice dynamics was measured by weekly salmon lice counting at a full-scale production facility from mid-summer 2019 to late-spring 2024. We monitored four production cycles, with AcuLice applied for two of the production cycles and with no AcuLice treatment applied during the other two production cycles as control. This is a follow-up study to our previous work. The numbers of salmon lice treatments and of weeks until the first salmon lice treatment were also compared in the two experimental groups. For the small (sessile and mobile stages) salmon lice, a significantly lower number (mean ± SEM) was shown for the AcuLice group (0.73 ± 0.03) compared with the control group (1.18 ± 0.05). For the mature female salmon lice, a significantly lower number (mean ± SEM) was found for the AcuLice group (0.12 ± 0.01) compared with the control group (0.22 ± 0.03). In addition, the mean (±SEM) number of C. elongatus varied between the two experimental groups and was higher in the control group (0.12 ± 0.01) compared with the AcuLice group (0.03 ± 0.01). In addition, a lower number (mean ± SEM) of salmon lice treatments (1.4 ± 0.17 vs. 4.22 ± 0.20) and a longer production period before the first salmon lice treatment occurred was observed for the AcuLice group (11.2 ± 0.1 weeks) compared with the control group (24.1 ± 2.3 weeks). These data suggest that the use of the AcuLice system significantly reduces the number of salmon lice (by 40–60%) and C. elongatus (by 70%) on farmed Atlantic salmon and reduces the need for traditional salmon lice treatments (by 65%). Full article

Background/Objectives: Habitual dietary changes that could help reduce the potential consequences of excessive body mass, such as hyperlipidemia and increased cardiovascular disease risk, are needed. The aim of this study is to assess the impact of a farmed-salmon-based dietary intervention on lipid profile parameters in young women with excessive body mass. Methods: The 8-week intervention involved 38 pair-matched women aged 18–30 years with excessive body weight defined as BMI ≥ 25.0 kg/m². Participants were randomly assigned to the intervention (200 g of smoked salmon weekly) or the control group. Lipid profile parameters (total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TAG)), as well as atherogenic indices (Atherogenic Index of Plasma (AIP), Atherogenic Coefficient (AC), Cholesterol Index (Cholindex), Castelli Risk Index 1 (CRI-1), Castelli Risk Index 2 (CRI-2) and the TAG/HDL ratio) were assessed before, during, and after the intervention. Results: At baseline, 47% of participants had at least one of the lipid profile parameters outside the recommended range. No statistically significant differences were observed in the TC, HDL, non-HDL, LDL, or TAG concentrations or in the various atherogenic indices between the intervention and the control group after the 8-week-long intervention. However, differences in the change of the LDL concentration were noted, with a decrease of 8.2 ± 20.7 mg/dL in the intervention group compared to an increase of 9.5 ± 20.0 mg/dL in the control group (p = 0.011), as well as in the change of the Cholindex for which a median decrease of 4.4 mg/dL was noted in the intervention group, while a median increase of 0.8 mg/dL in the control group was observed (p = 0.040). Additionally, across participants with a waist-to-height ratio (WHtR) greater than 0.5, an increase of 50.0 ± 68.3 mg/dL in the intervention group and a decrease of 8.6 ± 56.6 mg/dL in the control group was noted for the TAG concentration change (p = 0.040). Conclusions: Concerning the observed beneficial influence of increasing farmed salmon intake to the recommended fish-intake amounts on decreasing LDL and Cholindex in young women with excessive body weight after 8 weeks, it seems that such a diet alteration might be recommended for this group to decrease their risk of cardiovascular disease in the future. Nonetheless, regarding the diverse influence on TAG, further studies are needed to assess the influence of increasing the intake of fatty fish available on the market at present on human health. Full article