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The proliferation of salmon lice is one of the most challenging problems in salmon farming, seriously affecting the welfare of both farmed and wild salmonids. The detection of salmon lice in seawater, especially in the (pre-) infectious stage, supports the accurate management of salmon lice proliferation. Methods for detecting salmon lice in seawater to date involve traditional light and fluorescence microscopy and Polymerase Chain Reaction (PCR) methods. However, these methods require sample pre-processing and are laborious and time-consuming, rendering them difficult to apply for the task of continuous, rapid salmon lice detection in large water volumes. This study aims to develop a rapid and easy-to-use method for the detection of salmon lice in seawater. A novel approach was introduced for the detection of salmon lice at different larval stages in seawater by leveraging machine learning. A setup for the rapid acquisition of images of salmon lice in seawater was developed, and a dataset comprising 8316 images encompassing salmon lice "Nauplius Live," "Nauplius Shell" and "Copepodite" was created. Then 16 object detection models including one- and two-stage Convolutional Neural Network (CNN-) based models and Transformer-based models were trained, tested, and compared on this comprehensive dataset. RT-DETR showed the best performance among all models tested with a precision of 0.972 and a recall of 0.978. The YOLO series models, except for YOLOv3, showcased remarkable inference speeds (ranging from 152 to 416 frames per second) while maintaining high precision (ranging from 0.968 to 0.977) and recall (ranging from 0.964 to 0.970). To our knowledge, this is the first time machine learning has been applied to the task of rapidly detecting salmon louse larvae at different stages in seawater samples. The results demonstrate that the machine learning approaches can achieve rapid easy-to-use and cost-effective detection of salmon lice in seawater. In the future, this study has the potential for application in measuring salmon louse larvae numbers in aquatic environments, supporting the enhancement of the welfare of both farmed and wild salmon. • We used machine learning to detect salmon louse larvae at different stages in seawater for the first time. • Our image dataset contained 8316 images with salmon louse "Nauplius live," "Nauplius shell" and "Copepodite". • A total of 16 object detection models were compared with the YOLO series and RT-DETR models having the best performance. • We preliminary tested YOLOv8n in real seawater samples with good results. • It seems feasible to monitor the presence of salmon lice in seawater as a possible solution to the risk of infection of both farmed and wild salmon. [ABSTRACT FROM AUTHOR]

In fish, sex dimorphism generates benefits for farming when one gender displays better production traits than the other. In such cases, farming exclusively one sex becomes more profitable. The tambaqui (Colossoma macropomum) is the Brazilian native species with the highest production in the Brazilian fish industry. In tambaqui farming, it is more lucrative to produce females because they grow faster than males. As the species has the XX/XY genetic sex determination system, the use of XX neomales (masculinized genetic females) as breeders to produce solely all-female populations is the most sustainable approach. With the aim of obtaining tambaqui neomales, we tested three doses of mesterolone (1-α-methylandrosterone; at 10, 20 and 40 mg kg−1) through the diet of pre-differentiated juveniles for three months, to masculinize the females. The sex ratio and immediate and long-term effects on the physiology of the fish were evaluated by hematological and biochemical analyses of the blood plasma at the end of the treatment, and three months later. Possible hepatotoxic and mutagenic effects of mesterolone were assessed via liver histopathology, hepatic enzyme production and the micronucleus test (fragmented DNA) in the erythrocytes. The results indicate that 20 and 40 mg kg−1 of mesterolone produced over 76% phenotypic males, have no influence on growth and on the biochemical parameters, do not cause DNA damage, nor do they have toxic effects in the liver of tambaqui. A decrease in the hepatosomatic index and an increase in some hematological parameters were observed during the treatment, but all values were similar to the control three months after the end of the experiment. • 20 mg kg−1 mesterolone in the feed of tambaqui results in 77% of phenotypic males. • Mesterolone does not affect tambaqui growth. • Hematocrit, hemoglobin, erythrocyte, MCH and MCHC are immediately affected by mesterolone. • Mesterolone added to the diet does not cause mutagenic effects in tambaqui. [ABSTRACT FROM AUTHOR]

The Mediterranean mussel, Mytilus galloprovincialis Lamarck, 1819 is a widely distributed commercially important bivalve species, and is one of two cultivated bivalve species in the Adriatic Sea, with the Krka River estuary being a key aquaculture location. Understating the feeding ecology of M. galloprovincialis could help aquaculture be more efficient. The aim of this study is to use stable isotopes to advance our understanding of M. galloprovincialis feeding ecology, as well as explore the potential of their shell as proxies for environmental change. We analyzed stable isotope composition (hereafter, δ13C and δ15N), of M. galloprovincialis soft tissue, as well as the δ15N signature of its shell, over one year at multiple sites in the Krka River estuary. Mussels showed differences in the isotopic niche depending on the site, indicating that feeding varies according to geographic location, likely due to specific conditions in the Krka River estuary and differences in food availability. During our entire survey period, marine organic carbon was the dominant source in the mussels cultivated in the Krka estuary. However, in the period from late summer to late autumn, the contribution of freshwater carbon sources increased for both sites situated in the middle estuary. The distinct feeding patterns observed at each sampling site could be attributed to a combination of factors such as local hydrographic conditions, food availability, and the presence of other competing species. Overall, the stable isotope results present valuable information on the feeding ecology of Mytilus galloprovincialis , highlighting the complex interactions between environmental factors and feeding habits. The results of our study contribute to the isotope data archive for M. galloprovincialis. Furthermore, this work shows the potential of M. galloprovincialis shell δ15N values as an indicator for nitrogen loading in aquaculture settings and coastal marine environments. • Mytilus galloprovincialis in the Krka River estuary show spatial variation in feeding behaviour and carbon sources. • Krka River estuary offers a natural experimental design to explore spatial and temporal variability in shell geochemistry. • δ15N CBOM in Mytilus galloprovincialis shells has potential as proxies for environmental variations [ABSTRACT FROM AUTHOR]

Deviating heart shapes and poor cardiac health is a recurring concern in farmed Atlantic salmon. Morphometric analysis has so far improved our understanding of salmonid cardiac morphology, but assessment of morphological cardiac variation is usually performed manually through measurements of lengths, ratios, and angles. Manual assessment of heart shape is tedious, time-consuming, and not very standardized. It also requires training and alignment of personnel to achieve reliable results. Considering these challenges, we aimed to automate this process using a deep learning model for computer vision to measure the morphological variations of the heart. Here we developed an algorithm for a diagnostic tool to detect variation in cardiac morphology in farmed Atlantic salmon, which we believe can assess cardiac morphological variation in a more objective, reproducible, and reliable manner compared to the manual process. The knowledge derived from this study may represent a crucial step in comprehending and eventually reducing cardiac abnormalities in farmed salmonids, which is essential for improving fish health and welfare and ensuring aquaculture's sustainable growth. [Display omitted] • Automated measurements of Atlantic salmon cardiac morphology using computer vision. • Classification of cardiac morphology in Atlantic salmon using machine learning. • Comparison of hearts of farmed Atlantic salmon from Norway and the Faroe Islands. • Novel method may support risk assessments and sustainable growth in aquaculture. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila is a widely distributed Gram-negative waterborne pathogen responsible for large-scale outbreaks of hemorrhagic septicemia in fish, causing severe economic losses to the global aquaculture industry. In view of few therapeutic drugs currently available for use in aquaculture and the emergence of multidrug-resistant A. hydrophila , there is an urgent need to develop new antimicrobial agents as an alternative to antibiotics. Antimicrobial peptides (AMPs) have strong antimicrobial effects and unique machanisms of action, and are not easy to induce bacterial resistance, making them an ideal alternative to antibiotics. In this study, we identified a new functional gene from marine crab Scylla paramamosain , named Spasin, which encodes a mature peptide of 240 amino acids and expressed widely in various tissues of crabs. Notably, a truncated peptide Spasin 141 – 165 derived from Spasin, showed potent and broad-spectrum antibacterial and antifungal activity at minimum inhibitory concentrations (MICs) ranged from 0.75 μM–48 μM, which is a novel AMP. It effectively killed S. aureus and A. baumannii within 2 h and 90 min, respectively. Importantly, it is not toxic to HEK-293 T, RAW 264.7, and ZF4 cell lines. Mechanistic studies showed that addition of 8 μg mL−1 lipoteichoic acid or lipopolysaccharides decreased bacterial susceptibility to Spasin 141 – 165. In addition, Spasin 141 – 165 altered the permeability of the inner and outer cell membranes, and resulted in the release of ATP and the accumulation of intracellular reactive oxygen species. Notably, Spasin 141 – 165 significantly increased the survival rate of zebrafish infected with A. hydrophila , redcued the bacterial load in the spleen, and effectively inhibited the expression of inflammation-associated factors (e.g. , IL-1β, TNF-α, etc.). Taken together, Spasin 141 – 165 is a potential antibacterial agent for the treatment of A. hydrophila infections in aquaculture and a promising antibiotic alternative. • Identification of a potent antimicrobial peptide from mud crabs. • Spasin 141 – 165 killed pathogenic microorganisms by disrupting cell membranes. • Spasin 141 – 165 significantly improved the survival of zebrafish infected with Aeromonas hydrophila. • Spasin 141 – 165 remarkably inhibited the inflammatory response in zebrafish after Aeromonas hydrophila infection. [ABSTRACT FROM AUTHOR]

To evaluate the raw material digestibility, the physical characteristics of diet pellets and faeces, and the postprandial nitrogen excretion in greater amberjack (Seriola dumerili) reared in recirculating aquaculture systems (RAS), 10 diets were obtained by mixing a reference diet (CP: 51.8% DM; EE: 13.6% DM) with one of ten raw materials (7:3 ratio), i.e. fishmeal (FM), porcine haemoglobin (PH), fermented soybean (FS), soybean protein concentrate (SPC), hydrolysed wheat protein (HWP), potato protein (PP), beet pulp (BP), beer yeast without fat (BY), beer yeast with fat (BYF), and Lithothamnium seaweed (LS). Twenty fish (268.9 ± 94.3 g) were randomly distributed into 5 RAS tanks (4 fish per tank) and fed for 140 days the experimental diets. A Latin square experimental design was used based on 5 diets × 5 tanks for two rounds (10 ingredients, 2 weeks per diet per tank). The highest ADCs of dry matter and protein were recorded for PH (83.0% and 88.4%, respectively), FM (81.8% and 84.3%), SPC (77.4% and 82.5%), and BYF (73.0% and 80.9%) while the lowest ones for BY (64.4% and 70.8%), HWP (59.8% and 69.9%), PP (48.3% and 69.8%), and BP (53.7% and 55.8%) (p < 0.05). The ADCs of EAA were the highest for PH, FM and SPC compared to the other raw materials; ADCs of lipids was above 90% for all raw materials (p > 0.05). Regarding pellets properties, FM was associated with the highest value for oil leakage whereas BP to the lowest (0.18% vs. 0.11%; p < 0.05); FS, HWP, BYF, and PH produced less turbidity in water after 15 min than BY (3.68 mg L−1 on average vs. 6.01 mg L−1; p < 0.05). Regarding faeces size, fish fed FS, BYF, and FM produced the lowest volume of fresh faeces of fine-size class than those fed the other raw materials (62.1% vs. 69.2% on average; p < 0.05); the highest rate of dry faeces retained at a sieve mesh interval of 1.0 < mm < 1.2, was produced by fish fed BYF and the lowest rate by those fed BY (1.16% vs. 0.34%; p < 0.05). A maximum of postprandial nitrogen excretion (mg N-NH 4 + × kg fish −1 × h) was reached between 2 and 4 h after feed ingestion without differences among diets (p > 0.05). Overall, the findings of this investigation will contribute to the sustainable formulation of RAS aquafeed optimized and tailored for this promising Mediterranean aquaculture species. • Animal-based raw materials have the highest digestibility of protein and dry matter. • Beet pulp reduces oil leakage of diets. • Plant-based raw materials and beer yeast reduce water turbidity. • Fermented soybean and fishmeal produce large fish faecal particles. [ABSTRACT FROM AUTHOR]

Villorita cyprinoides (Gray, 1825) also called the Indian black clam is a native species from the Indian peninsula directly related to the livelihood of many beneficiaries. The wild population of this Cyrenid clam is confronted with substantial challenges, including various climatic stressors and anthropogenic pressures such as overfishing and habitat destruction. A balance between capture fisheries and aquaculture through the development of hatchery technology is inevitable for ensuring the sustainable use of resources. The declining population of V. cyprinoides underscores the urgency of standardizing breeding protocols and implementing proper farming practices to foster a sustainable black clam fishery, given that Villorita is a potential candidate species for aquaculture. This paper describes the first successful induced spawning of the clam with successful rearing of larvae up to the umboned veliger stage and evaluates the efficacy of induced spawning through combined physical and chemical stimuli. Furthermore, our study employs eDNA metabarcoding to analyze plankton dynamics in waters from native clam beds. This sheds light on the potential microalgal dietary preferences of the species, which can be valuable in preparing diets for larval development and aquaculture in the future. • The first successful report on induced spawning in Villorita cyprinoides was achieved through physical and chemical stimuli. • Induced spawning indicated, V. cyprinoides as a potential candidate species for aquaculture with streamlined protocols. • Statistical analyses showed a significant correlation between physical stimuli and spawning. • eDNA metabarcoding revealed the dominant biota in the natural bed of black clams during peak breeding season. • The effective implementation of NGS provides initial insights into the advancements of artificial diet formulation. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) related mass mortality events in land-based recirculating aquaculture systems (RAS) are associated with the sudden release of substantial amounts of H 2 S, resulting in acutely toxic exposure. However, the production and release of H 2 S can also occur at slower constant rates, leading to continuous exposure to sublethal H 2 S concentrations, the effects of which are unknown. Here, we examined growth rates, feed conversion ratios, and apparent nutrient digestibility in post-smolt Atlantic salmon, following a 10-day exposure to one of two sublethal concentrations of H 2 S, compared against a control group. The H 2 S concentrations of the low exposure (LE) and moderate exposure (ME) groups throughout the trial were 1.8 ± 0.8 μg/L and 4.1 ± 1.9 μg/L, respectively. Neither exposure regime affected growth, feed utilization, or the apparent nutrient digestibility. The results suggest that Atlantic salmon tolerate exposure to sublethal H 2 S concentrations for 10 days, without a discernible effect on the production performance. For aquaculture systems, specifically RAS, this means that while higher concentrations of H 2 S should be strictly avoided, the presence of low H 2 S concentrations for a limited period might not be detrimental to fish welfare or production. The RAS environment is complex, and the potential combined effects of H 2 S and factors pertinent to RAS may influence fish performance differently in a production setting. • Atlantic salmon (Salmo salar) were exposed to two sublethal H 2 S concentrations for 10 days. • Exposure to low (1.8 ± 0.8 μg/L) and moderate (4.1 ± 1.9 μg/L) H 2 S regimes did not affect the growth. • FCR and apparent digestibility coefficients (ADCs) were similar between the treatments. • Exposure to either H 2 S regime did not have a significant effect on the production performance. [ABSTRACT FROM AUTHOR]

Despite the growing emphasis on aquatic disease monitoring via environmental DNA (eDNA) in water samples, detecting low concentrations of viruses in aquatic environments remains challenging. Prior studies demonstrated that plankton act as mechanical vectors for several aquatic viral pathogens but not for the viral hemorrhagic septicemia virus (VHSV). In this study, we aimed to identify the potential interaction between VHSV and microplankton and further assess the effectiveness of the water concentration method using a plankton net for VHSV detection in water. Briefly, VHSV was co-cultured with Chlorella , rotifer, and microcosms generated using plankton nets with sieve sizes of 20, 40, and 70 μm. A close interaction between VHSV and rotifer and microplankton collected with the 70 μm-plankton net with an abundant zooplankton population was found, likely influenced by the filter-feeding behaviors of zooplankton. We also found that VHSV could adsorb to fish feces at concentrations 25–88 times higher than that in the equivalent volume of seawater. Subsequently, we evaluated the efficiency of a 70 μm-plankton net for VHSV concentration in rearing water containing infected fish compared to the iron flocculation method. Notably, the plankton net outperformed the iron flocculation method in terms of sensitivity (∼10 to 20-fold), possibly due to its ability to capture fish-derived organic materials, such as feces, shed from infected fish. Our overall findings advocate for the plankton net concentration approach, not only for its pronounced sensitivity but also its operational simplicity, identifying it as a promising avenue for efficient VHSV detection in aquaculture water monitoring. • This study demonstrates an association between VHSV and microplankton. • Concentration of rearing water using a plankton net outperformed iron-flocculation in terms of viral detection. • The plankton net method, with its operational simplicity, can be an effective eDNA tool for monitoring aquatic diseases. [ABSTRACT FROM AUTHOR]

Microeukaryotes play a crucial role in maintaining microbial diversity and stability of aquaculture pond ecosystems. Despite their importance, our understanding of microeukaryotic community assembly and temporal dynamics throughout the aquaculture cycle remained limited. This study investigated microeukaryotic community dynamics in nine shrimp (Litopenaeus vannamei) farming ponds over 60 days using 18S rRNA gene sequencing. The results indicated that microeukaryotic community dynamics in the pond system can be divided into two stages: a fluctuating stage from day 0 to day 40 and a stable stage from day 40 to day 60. The alpha diversity of the microeukaryotic community in sediment increased in the first stage and decreased in the second stage, while it remained relatively stable in water. The community structure, network complexity, and stability of the microeukaryotic community in water were more stable in the second stage than in the first stage. Additive partitioning analysis indicated local diversity and within-habitat variation were the primary contributors to the total microeukaryotic metacommunity diversity of aquaculture pond system. Furthermore, the species pool in both water and sediment primarily originated from historical sources within the microeukaryotic metacommunity, and the dispersal route between habitats (water and sediment) was strengthened in the second stage compared to the first stage. Additionally, the assembly of microeukaryotic community was primarily governed by stochastic processes in the first stage and deterministic processes in the second stage. Specifically, increasing nitrogen loading influenced the relative abundance of dominant green algae and strengthened the homogeneous environmental selection of the microeukaryotic community. Overall, this study demonstrates the significant impact of historical species pool and nutrient loading in structuring the microeukaryotic metacommunity in the aquaculture pond system. • Microeukaryotic communities fluctuated early but stabilized in later stages. • Dispersal between habitats increased over time, but historical sources remained primary contributors to species pools. • Community assembly shifted from stochastic to deterministic with more nutrients. • Dominant green algae drove assembly patterns and were influenced by nitrogen compounds. [ABSTRACT FROM AUTHOR]

Like other vertebrates, fish exhibit physiological and behavioural rhythms that are synchronized by the cyclic variations in the external environment, being photoperiod, i.e. , the alternation of light and dark during the 24-h cycle, the most predictable and powerful environmental cue. Many of these rhythms are endogenous and controlled by a molecular clock present in cells from early developmental stages. In a previous study, we have developed and characterised a new monoclonal embryonic stem cell line, SAEC-H7, derived from the morula stage embryos of a marine teleost, the gilthead seabream (Sparus aurata), a species with high commercial value for European aquaculture. In the present study, we aimed to identify the main components from the positive (clock and bmal1) and negative (cry1a , per1 , per2 and per3) feedback loops of the molecular clock in this embryonic cell line and characterise putative daily variations and circadian rhythms in their expression under different photoperiod regimes, as well as the effects of nocturnal light pulses on their transcriptional activation. Our results revealed that SAEC-H7 cells contain a molecular clock that is entrained by the daily light-dark (LD) cycle. All clock genes analysed showed daily rhythms under LD conditions and were able to re-entrain to a 12-h phase shift (DL) in the photocycle, some of them (clock , bmal1, per1 , per3) exhibiting circadian rhythms that persisted over a certain period under constant conditions, although with affected amplitudes and acrophases. Both cry1a and per2 genes showed a statistically significant increase in expression after a nocturnal light pulse, confirming the light-inducible character of these clock genes. The results obtained reveal that seabream embryonic cells are highly sensitive to light and already contain the phototransduction pathways that entrain the molecular clock and overt rhythms from the morula stage, making this embryonic cell line a useful tool for developmental and chronobiological studies in fish. Our results also reinforce the importance of maintaining natural cyclic light conditions in in vitro studies performed with fish cell lines as well as in embryonic and larval rearing protocols in aquaculture practices. • An embryonic stem cell line was used to characterise the clock machinery of Sparus aurata. • SAEC-H7 cells contain a molecular clock entrained by the daily light-dark cycle. • Some clock genes showed circadian rhythms that persisted under constant conditions. • Natural cyclic light conditions are recommended in rearing protocols in aquaculture. • SAEC-H7 cells are a useful tool for developmental and circadian studies in fish. [ABSTRACT FROM AUTHOR]

In recent years, the rapid development of the large-scale aquaculture industry has generated substantial economic benefits, positioning it as one of the fastest-growing sectors in global agricultural production. However, improper management practices in aquaculture, including overfeeding, improper feed selection, antibiotic misuse, high stocking densities, inappropriate choice of aquaculture species, and improper discharge of aquaculture wastewater, have resulted in significant watershed pollution in agriculture and the wastage of valuable resources. To address these challenges, extensive research and application of wastewater treatment technologies have been conducted in large-scale aquaculture in China. This review provides an overview of current cases and applications of wastewater treatment in large-scale aquaculture in China, focusing on four common intensive wastewater treatment methods: constructed wetland treatment model, ecological ditch treatment model, Integrated Multi-trophic Aquaculture model, and recirculating aquaculture model. The constructed wetlands utilize plants and microorganisms to purify both organic and inorganic pollutants in water, while ecological ditches employ engineering measures such as sedimentation ponds, interception ditches, and aeration devices to achieve wastewater treatment. Additionally, other aquaculture models are highlighted, such as Integrated Multitrophic Aquaculture (IMTA), which emphasizes synergistic interactions between aquaculture species and the recycling of nutrients, and the Recirculating Aquaculture Systems (RAS), which utilize water circulation and treatment equipment for wastewater treatment. The consequences and benefits of these systems in pollution reduction are described. These treatment technologies have made significant progress, offering theoretical guidance for environmentally friendly aquaculture production and the maintenance of ecological stability in aquaculture water bodies. Each wastewater treatment model has a different function, target, and methodology. Finally, this paper proposes directions and recommendations for future pollution management in large-scale aquaculture in China, including strengthening technological research and development, the combined application of multiple treatment models, promoting industry collaboration, and achieving resource sharing. These efforts will contribute to further promoting the sustainable development of China's aquaculture industry and provide valuable experiences and references for other countries and regions. • CWs and ecological ditch use plants and microorganisms to purify wastewater. • IMTA maximizes species interactions for efficient nutrient cycling. • RAS uses equipment to remove pollutants from aquaculture water for recirculation. • Utilizing multiple purification modes can enhance wastewater treatment efficiency. [ABSTRACT FROM AUTHOR]

For food safety challenges, sustainable aquaculture emerges as a significant source in recent years; however, despite its potential, the industry still facing challenges, notably the exposure of cultured animals to pesticidal pollution. This pollution originating from agricultural practices that can enter aquaculture system directly: to integrated-agriculture aquaculture practices, or indirectly via soil leakage. Current research based on glyphosate (GLY) toxicity and its amelioration by lycopene (LYC). Four fish groups used for six-weeks experiment in which four groups were used. Control group (CL) was fed with basal commercial diet only without any LYC and GLY exposure; 2) LYC group: exposed to LYC supplemented diet (15 mg/kg per fish diet); 3) GLY group: exposed to glyphosate only (1/5th of 96 h LC 50 : 0.0892 mg/L) with basal commercial diet, and; 4) GLY + LYC group: exposed to both lycopene supplemented diet (15 mg/kg per fish diet) and glyphosate (1/5th of 96 h LC 50 : 0.0892 mg/L). GLY observed to decrease growth parameters and feed utilization whereas, lycopene ameliorated growth rate (WG, SGR, HSI, CF) and feeding utilization (FCR) as compared to the control group. Also, GLY induced toxicity within hematobiochemical parameters with alleviation by LYC supplementation. GLY induced cytotoxicity was observed within RBCs as lobbing, notching, vacuolation, blebbing, micronuclei, and condensation. Increase in reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) were observed by GLY exposure. Also, there is observed reduction in antioxidant enzyme activities (CAT, SOD, POD, TPC and GSH) upon GLY exposure. Lipid peroxidation (malondialdehyde: MDA), 8-OHdG (8-hydroxy-2′-deoxyguanosine) and DIY (dityrosine) observed to increase by GLY toxicity. There was improvement in immune responses; increased AChE (acetylcholinesterase) activity, lysozyme content, ACP (acid phosphatase), NBT (nitro blue tetrazolium), NO (nitric oxide) and IgM levels (immunoglobulin M) and digestive enzyme activities (protease, lipase and amylase) observed by LYC supplemented diet. Taken together, LYC supplementation observed to alleviate GLY induced oxidative stress and cytotoxicity with improved immunity, digestive actions and blood health within C. carpio. Therefore, dietary supplementation with lycopene can protect common carp from the harmful effects by glyphosate within agri-integrated aquaculture practices, so suggesting it as potential feed additive. [Display omitted] • GLY negatively impacted growth and hematobiochemical parameters in common carp. • LYC ameliorated growth rate and alleviated GLY-induced cytotoxicity in RBCs. • GLY exposure increased oxidative stress and lipid peroxidation. • LYC supplementation improved immunity and digestive enzyme activities. • LYC is potential feed additive for common carp culture. [ABSTRACT FROM AUTHOR]

Ostreid Herpesvirus - 1 is a global threat to Pacific oyster aquaculture as catastrophic farm losses have occurred where OsHV-1 microvariants (μvars) become endemic. Genetic selection has proven effective for increasing survival to OsHV-1 exposure in multiple Pacific oyster breeding programs, but a novel μvar detected in San Diego Bay California has the potential to severely impact commercial aquaculture along the North American Pacific coast as no OsHV-1 μvar selected population is available commercially. Using a Molluscan Broodstock Program population descending from imports originating in the Miyagi prefecture (Japan), we evaluated the potential for genetic selection to improve survival against the San Diego Bay OsHV-1 μvar using a laboratory trial. Two experimental methods were evaluated, a common garden method where all 15 full-sibling families were pooled, and a petri dish method, where each family was confounded within replicate. No striking differences were found between experimental methods, and both experiments displayed high heritability (0.69 and 0.64) of the tested trait, a broad range of estimated breeding values, and a moderate prediction accuracy for the survival trait. A significant genotype-by-environment interaction occurred, highlighting variability in laboratory-based disease challenges, but the two experiments yielded similar results with minor to moderate re-ranking of mean family survival. Overall, the Miyagi population of Pacific oysters curated by the Molluscan Broodstock Program is a promising population to use for artificial selection to increase survival against San Diego Bay OsHV-1 μvar in attempts to obviate farm losses if the virus expands its currently isolated range. • High heritability and sufficient variation exist in a Pacific oyster population for genetic selection to improve survival after exposure to a OsHV-1 μvar from the North American Pacific coast. • Only nuanced differences exist between single family and common-garden experimental assay methods. [ABSTRACT FROM AUTHOR]

This study uses a circular economy-regenerative value addition approach. Pre-treated waste clam shells were calcined at a low temperature (about 300 °C) and then crushed into clamshell powder. Taiwanese hard clam shell (THCS) powder and commercially available calcium carbonate products, such as low-temperature calcined oyster shell (OS) powder, slaked lime, and calcium carbonate, were compared experimentally, and the safety of THCS powder was determined. In the safety evaluation, the Vibrio -like bacteria test results showed that no colony growth was found for the low-temperature-calcined THCS powder, indicating that it did not contain Vibrio -like bacteria. Tolerance test results showed that high-dose slaked lime will cause high Taiwanese hard clam mortality, and the survival rates of other groups were all 100%. In addition, slaked lime had the most significant effect on increasing the water pH. OS powder had the greatest effect on increasing the calcium ion concentration in the water, followed by THCS power. The aquaculture benefit-related experimental results showed that the low-temperature calcined OS powder and THCS powder groups had the most favorable performance in terms of Taiwanese hard clam growth rate, shell weight, and shell thickness. This study used different calcium carbonate products as additives in Taiwanese hard clam aquaculture ponds and observed growth differences between the different groups. These results indicated that the low-temperature calcination of THCS in Taiwanese hard clam aquaculture can effectively replace the commonly used OS powder, slaked lime, and calcium carbonate products in traditional aquaculture. Furthermore, it can effectively solve the problem of THCS waste accumulation, promote environmental beautification, create a circular economy and aquaculture application value, and conform to the economic benefits of aquaculture. • SEM reveals a smooth surface structure of low-temperature calcined THCS powder. • This THCS powder is safe after testing for Vibrio -like bacteria and tolerance. • This THCS powder effectively increases the calcium ion concentration in water. • This powder can effectively replace conventional chemicals (e.g., oyster shell powder, slaked lime, and CaCO 3). [ABSTRACT FROM AUTHOR]

Optimization of ideal stocking density in intensive aquaculture system is a challenging appraisal. Higher stocking density is inducing chronic stress, impacting negatively on physiology and increasing disease associated risks in fish. Hence, the study was designed to evaluate the water quality, growth performance, health status and flesh quality of striped catfish (Pangasianodon hypophthalmus). The fish (2.61–2.64 ± 0.01 g initial body weight) were reared in randomly designed variable stocking densities (SDs) including five treatments (30, 40, 50, 60 and 70 fish m−3) in triplicates at C:N ratio 15:1 in jaggery supplemented biofloc system for 120 days in 1000 –L experimental fiber-reinforced plastic tanks. SD30 acted as control treatment having low stocking density. During the culture, pH, alkalinity and dissolved oxygen level decreased and BOD increased with increased stocking density. TDS and TSS level increased upto SD50 treatment and further decreased in higher stocking density treatments. Higher population of heterotrophic, ammonifying and nitrifying bacteria significantly (p < 0.05) reduced TAN, NH 3 -N, NO 2 -N, and elevated NO 3 -Nas well as rate and potential of ammonification and nitrification in SD50 treatment than other treatments. Bacillariophyceae and protozoa were most dominant group in the biofloc microbiome in all the treatments. Highly elevated biofloc volume, floc microbiome, good floc characteristics and floc quality might have enhanced fish survival rate, body weight gain, SGR through improving FCR in SD50 than other SDs. Moreover, higher population of gut microbiota (TPC and probiotic) and elevated digestive enzymes activity in fish reared in SD50 treatment significantly (p < 0.05) enhanced PER, ANPU, and somatic indices (GSI and HSI) as well as enhanced colour (lightness, yellowness/blueness and whiteness), flesh quality and hardness. Fish reared in SD50 treatment showed significantly (p < 0.05) higher haematological (TEC, TLC and Hb), immunological (TSP, albumin, RBA and lysozyme), antioxidant responses (higher SOD and CAT) and lower metabolic stress enzymes responses (ALT, AST and glucose). Moreover, fish reared in SD50 treatment showed improved villi surface area and height in intestine and slightly vacuolated hepatocytes in liver. Overall, significantly (p < 0.05) better water quality, fish performance, health status and flesh quality were observed in SD50. Collectively, the findings suggest that farmers can be benefitted by fetching higher production through suitable stocking density (50fish m−3) of P. hypophthalmus in biofloc with improved water quality, growth performance, health status and flesh quality. • The stocking density plays a pivotal role in providing optimumconditions for overall performance of striped catfish. • Stocking density could significantly affect water quality and bacterial population. • Higher stocking density adversely affected survival rate, SGR, FCR, gut microbiota and digestive enzymes of striped catfish. • Higher stocking density induced stress and significantly affected immune-haematological responses of striped catfish. • Stocking density of striped catfish (50 fish m−3) in biofloc system may be recommended for farmers for sustainable fish production. [ABSTRACT FROM AUTHOR]

Aquaculture policies that decrease the reliance on wild-caught fish and promote integrated multi-trophic aquaculture (IMTA) both aim to lessen the environmental footprint but often overlook economic-environmental trade-offs and neglect social, health, and broad-scale sustainability considerations. Here we present a new bio-physical model (FYNE) that bridges some of these gaps, by linking farm operational choices, such as feed choices and farm siting, with the nutritional value of the farm-gate seafood products and the resulting environmental eutrophication footprint at the farm level. The FYNE model operates both in conditions of monoculture or of IMTA production, and estimates feed composition effects on growth and omega-3 fatty acid content of Atlantic salmon (Salmo salar) and blue mussel (Mytilus edulis) , and nitrogen and carbon concentrations, the latter being a measure of the environmental eutrophication footprint of the farm. The model here developed integrates for the first time (i) an ecosystem model of an IMTA and (ii) a fatty acid dynamics model, with new models for salmon feed digestibility and mussel ingestion. The outputs span (i) production analysis for simulation of biomass; (ii) farm mass-balance analysis on deposition analysis and environmental eutrophication footprint; and (iii) product nutritional quality, in terms of fatty acid content. An application of the model to an IMTA farm in Scotland (UK) demonstrates how fatty acid and environmental changes can be modelled in tandem and could be used to support the industry to optimize the nutritional value of cultured species and manage aquatic environmental eutrophication footprint at farm level, informing feed and siting decisions. The model effectively predicts changes in omega-3 fatty acids, particularly DHA and EPA, in response to variations in feed composition. Notably, our results confirm that salmon waste has limited influence on mussel growth due to the spatial separation within the IMTA system, which emphasizes the need for strategic siting to enhance system productivity through effective waste recycling. Additionally, results show that while increasing fishmeal in diets enhances environmental outcomes, it reduces levels of critical fatty acids like DHA and EPA, underscoring the need for balanced feed formulations. The method developed in this study described a novel integrated model (FYNE) that extend previous modelling work by incorporating the influence of farmed species feed composition on fatty acid dynamics as well as the farming environmental factors. • Salmon and mussel fatty acid dynamics linked to growth models and environment. • Models influence of feed on IMTA species nutritional quality and environment. • Model replicates the changes in salmon PUFA content relative to dietary PUFA content over a growth cycle. • Integration of PUFA models with IMTA ecosystem model. • Models the relationship between diet composition, fatty acid content, and environmental footprint. [ABSTRACT FROM AUTHOR]

Aquaculture is a crucial sector for Egyptian food production, providing a cheap source of animal protein while securing income and employment for a substantial part Egypt's population. Nile tilapia (Oreochromis niloticus) is the most commonly produced fish, usually farmed in earthen ponds around the Northern Delta Lakes. A common practice among farms is to fertilize ponds with chicken manure (CM) in order to increase nutrient levels and promote phytoplankton, consumed by the fish. However, with reports of use of antibiotics in Egypt's poultry sector, and that CM contains residues of antibiotics, antibiotic resistant pathogens and antibiotic resistance genes (ARGs) are production benefits large enough to compensate a potential health hazard? Using production data from 501 aquaculture farms and fish pond sediment from 28 ponds we evaluated potential benefits in yields and profitability for farms using CM for fertilization, and used qPCRs to screen sediments for three antibiotic resistance genes coding for resistance to the most commonly used antibiotics in the poultry sector. The analysis showed no significant benefits to fish yields or profitability in farms where CM was applied, but a risk of significantly increased nutrient loads. Meanwhile, we detected increased abundances of tetA and tetW resistance genes in fish pond sediment where CM was applied. With the risk of disseminating ARGs and causing eutrophication of local waterways, we recommend that Egyptian tilapia pond farmers refrain from using CM and adopt best management practices for increasing farm profitability in order to to reduce environmental and health hazards. • Consequences of fertilizing tilapia ponds are investigated across Northern Egypt. • Chicken manure addition increases eutrophication potential but not profitability. • Positive correlation between fertilization and abundance of resistance genes. [ABSTRACT FROM AUTHOR]

The increase in aquaculture activity is inevitable to fulfil global food provisioning for a growing population. Therefore, it is most recommendable to develop a sustainable approach for aquaculture practice. Integrated Multi-Trophic Aquaculture (IMTA) is proposed as one solution taking advantage of circular uptake of nutrients within the system. IMTA practice has been conducted for a thousand years despite only gaining recognition in recent decades. It is suggested to have lower environmental impact while promoting more advantages in the social and economic aspect of the industry. Therefore, multi aspects perspective of Life Cycle Assessment (LCA) is valuable to demonstrate the benefits of the system compared to the others. This review analyses 29 LCA studies on IMTA systems from 2009 to 2022 to understand the results, challenges, limitations, and benefits of LCA methodologies on IMTA systems. The studies followed the ISO 14040/44 guideline and were selected using the Google Scholar research tool. The four stages of the LCA were evaluated and it was concluded that there are several challenges in the Goal and Scope definition phase to determine the functional unit and methods that will be utilized. Hence, it is valuable to evaluate more options and, whenever possible, to conduct sensitivity analysis to help determine the proper methodology. The development of a specific database for the aquaculture sector is also strongly recommended, together with a standardized methodology for Data Collection and definition of impact categories to improve the consistency and comparability of the studies. Feed, fish effluents, and energy use are the impact hotspots and improving these factors might decrease the total impacts of the system as well. From this review, the potential of IMTA systems compared to monoculture systems and the potential of applying a tool such as LCA to measure it is highlighted. Therefore, more studies need to be conducted to improve the LCA methodology's consistency and reliability for IMTA system assessment. • IMTA systems have several advantages to aquaculture industry. • LCA compares the environmental impacts of different systems configuration. • LCA standardized methodology for IMTA assessment is required. • It is recommended the creation of a specific database for the aquaculture sector. • Feed, fish effluents, and energy use are the impact hotspots of IMTA systems. [ABSTRACT FROM AUTHOR]

The global shellfish aquaculture industry has expanded over the last seven decades. Similarly, the size of individual shellfish farming operations has grown in some states. Circulation processes in natural water bodies are dynamic and vary across multiple temporal and spatial scales. How gear installation affects the circulation of currents and waves, and subsequent phytoplankton delivery to crops within farms, is largely unknown. Documenting and understanding variability in wave and current energy within an individual farm could help optimize production. Our study sought to understand the variability in oyster growth attributable to hydrodynamic and atmospheric forcing across an active commercial shellfish aquaculture lease in the Patuxent River, Maryland. We observed a 17 % reduction in water flow downstream of the farm (rho = −0.673, p = 0.002, Spearman rank test), suggesting the bottom cages attenuated downstream current velocity during flood tides. Differences in flow speed and the movement of cages and oysters throughout the farm correlated with variances in oyster shell morphology and oyster survival while in bottom cages. Our results demonstrate the occurrence of variability in production within an individual farm location. Further, our findings suggest that insight into the spatial growth patterns across a lease can be practical for forecasting growth and quality of cultured oysters and may enable growers to strategically place oysters within their farm to improve yield and product consistency. • Attenuation of current velocity by oyster bottom cage aquaculture observed • Wind speed did not alter cage and oyster movement in a current-driven system. • Variability in oyster growth across one farm correlates with physical forcing. • Physical forcing can be used as a predictor of cultured oyster growth and quality. [ABSTRACT FROM AUTHOR]

Local aquaculture production of marine finfish has potential to meet the domestic seafood demand and contribute to reduction of the United States (U.S.) seafood trade deficit. The United States Department of Agriculture-Agricultural Research Service, along with other research programs, has developed aquaculture production technologies for warmwater marine finfish species with potential for commercial production. To understand the marketing opportunities for the candidate species, an online survey of 818 seafood consumers in the southeastern U.S. was conducted to explore their awareness, familiarity, frequency of consumption, location of purchase, and likelihood of purchasing the species of interest. A binary logit model was specified to explore the factors that influenced consumers likelihood to purchase Atlantic cod, black sea bass, California flounder, California yellowtail, Florida pompano, redfish, red snapper, southern flounder, spotted seatrout, striped bass, summer flounder, and white seabass, the 12 species for which there were at least 100 survey responses. This study focused on consumers likelihood to purchase the candidate species at grocery stores and restaurants. The results show that consumers who placed high importance on source of the fish and quality were more likely to buy various candidate species including red snapper, striped bass, Atlantic cod, southern flounder, Florida pompano, California yellowtail, black sea bass, California flounder, and white seabass. Respondents who considered price to be important were more likely to buy California flounder, redfish, red snapper, white seabass, black sea bass (at grocery stores only), and summer flounder (at grocery stores only). Frequent consumers of Atlantic cod, southern flounder, California flounder, redfish, summer flounder (at grocery stores only) and California yellowtail (at grocery stores only) were more likely to purchase these species. Frequency of consumption, seasonality in consumption, and demographic characteristics, including income, age, race, and state of residence, influenced consumers likelihood to purchase various species of interest. • Quality, source, and packaging are identified as the most important factors for marine finfish consumers. • Respondents who placed higher importance on source and quality attributes had a higher probability of purchasing red snapper, striped bass, Atlantic cod, southern flounder, Florida pompano, California yellowtail, black sea bass, California flounder, and white seabass. • Those who considered price to be important were more likely to buy California flounder, redfish, red snapper, white seabass, black sea bass (at grocery stores only) and summer flounder (at grocery stores only). • Frequent consumers of Atlantic cod, southern flounder, California flounder, redfish, summer flounder (at grocery stores only), and California yellowtail (at grocery stores only) were more likely to purchase farmed sources of these species. [ABSTRACT FROM AUTHOR]

Freshwater fishponds are an important part of the global aquaculture fish production, but they also are a source of invasive species with potentially negative impacts on pond ecosystems. In this study, we investigated dietary competition between common carp (Cyprinus carpio) and two invasive cyprinids, Pseudorasbora parva and Carassius gibelio , in fishponds of Central Europe. Using δ 13C and δ 15N stable isotopes analysis, we evaluated the extent of isotopic niche overlaps and the utilization of dietary sources by these species in fishponds that differ in the intensity of fish production. The isotopic niche of C. carpio and the invasive cyprinids overlap more in ponds with intensive (south-eastern Czechia) and semi-intensive (northern Austria) fish production then in ponds with low intensity production (eastern Slovakia). Our results also suggest that both invasive species opportunistically adjust their diet to their gape size and that they predominantly assimilate dietary energy from zooplankton and macroinvertebrates rather than from primary producers and detritus. Our study highlights the high potential of these invasive cyprinids to compete with C. carpio in fishponds of Central Europe. • Study of dietary overlap between common carp and invasive cyprinids in fishponds. • Isotopic niche overlap is higher in intensive and semi-intensive fishponds. • Low production intensity ponds show less dietary competition and niche overlap. • Invasive cyprinids in fishponds mainly consume zooplankton and macroinvertebrates. • Invasive cyprinids can have negative impacts on fishpond ecosystem and production. [ABSTRACT FROM AUTHOR]

The allocation of zones for aquaculture development is a strategic problem as it involves long-term outcomes and many stakeholders with competing interests. Resource planners require tools to support such complex allocation decisions, but these are either lacking or with serious limitations. This paper presents an approach that improves the traditional method of developing aquaculture zoning model. Four scenario narratives describing potential development pathways for aquaculture in Nigeria were used to guide the model development, from selection of suitability factors to evaluation of alternatives. The modelling objective was to identify a suitable location for zoning small-to-medium scale commercial pond catfish production in Nigeria. So, a GIS-based multi-criteria evaluation (MCE) was used to produce a suitability map, from which five alternative zones were extracted. These zones were then compared using three sustainability criteria that were designed based on future uncertainties highlighted by the four scenarios. Results show that 4 of the 5 zones are concentrated in the north-eastern part of Nigeria, while the other one occurred in the north-west. Furthermore, this study found two top-ranking zones that can be selected in all the scenarios, meaning the two zones with the most potential to support the sustainable development of small-to-medium scale aquaculture in Nigeria. As these two were almost tied in ranking, sensitivity analyses across the scenarios revealed the most stable zone to changes in the criteria scores. These findings can be used to inform aquaculture expansion policy in Nigeria and integrate the activity into wider land use planning. Overall, the new approach advances the traditional method of developing GIS-based MCE models for aquaculture zoning, as it generates options and relevant information to facilitate strategic decision-making. • Aquaculture zoning is a strategic problem requiring comprehensive tools. • Traditional suitability models for aquaculture planning not equipped to evaluate outputs. • New modelling approach developed, considering uncertainties in long-term planning. • Approach enhances decision support for zoning implementation. [ABSTRACT FROM AUTHOR]

Increasing societal conflict around natural resource extraction industry operations has given rise to the argument that - in most locations – these operations do not hold a social license to operate (SLO). This has led to substantial theoretical development of the SLO concept, yet the empirical grounding of this theory has not kept pace. This study tested five hypotheses regarding those factors that may influence the achievement or withdrawal of an industry's SLO, using Tasmanian aquaculture as a case example. The results found strong support for one hypothesis, weaker support for two hypotheses and no support for two hypotheses. This reinforces the importance of theory-testing, to identify where there is support or not for hypotheses, to foster curiosity regarding why, and to identify where further knowledge is needed. To better balance natural resource extraction with human needs, we must continuously challenge the theories proposed in this rapidly developing field. • Substantial theoretical development of Social License to Operate (SLO) concept but testing has not kept pace. • Five SLO hypotheses tested using Tasmanian aquaculture as a case example. • Strong support for perceptions of sustainability influencing SLO. • Weak support for perceptions of procedural fairness and actor trustworthiness influencing SLO. • Challenging SLO theories will help to better balance natural resource use with societal needs. [ABSTRACT FROM AUTHOR]

Shrimp aquaculture has experienced a significant global growth in the past twenty years, making a huge contribution to economic revenue. However, the emergence of Acute Hepatopancreatic Necrosis Disease (AHPND) imposed a huge economic, welfare, and environmental burdens to aquaculture sector globally. In this review, we emphasized on two key applications on AHPND treatment and AHPND diagnosis through the lens of metallic nanoparticles (MNPs) interventions. We review the potentialities and implications of MNPs through accumulated evidence and focussed investigations specifically targeting the AHPND causative agent, Vibrio parahaemolyticus, to improve the understanding of MNPs application from shrimp aquaculture perspective. MNPs treatment offers a novel antibacterial application, providing a new alternative to antibiotic therapy in combating AHPND, but also the implication from toxicological perspective challenges the integration of this technology into aquaculture disease management and treatment applications. We examine how the toxicological considerations have impacted the direction of MNPs synthesis in aquaculture research, aiming to produce MNPs that are biocompatible and suitable for aquaculture disease and treatment program. The lack of practicality in the diagnostic approach for AHPND hindered easy practise of disease detection among shrimp farmers. Thus, we also explore how the incorporation of MNPs into the existing AHPND diagnostic approach has been improved, leading to the development of a practical and user-friendly diagnostic tool for detecting V. parahaemolyticus. Application of nanotechnology through MNPs integration into AHPND treatment and diagnosis has big potentials to improve the disease management strategy, potentially revolutionizing shrimp aquaculture on a global scale. [ABSTRACT FROM AUTHOR]

It is known that the insulin-like growth factor (Igf) system is involved in gonadal development and, in turn, reproduction in vertebrates. In this study, the circulating levels of Igf-1 and follicle-stimulating hormone (Fsh) were assessed as physiological signals related to gonadal maturation stage in juvenile male European sea bass at 1 year of age. The seasonal profiles of Igf-1 and Fsh were analyzed in non-precocious (NP) and precocious (PR) fish during the early onset of puberty. Subsequently, gonadal expression patterns of the three igf genes and their two receptors, igf-1r and igf-2r , were studied during their first year of life. The analysis was continued to evaluate the mRNA expression profiles of three genes (sox17 , scf , nf2) mediating spermatogenesis progression. Collectively, these results demonstrated that PR males have higher circulating levels of Igf-1 as compared to NP fish before and during the putative gonadal development period (PGD). Plasma Fsh levels were significantly higher in PR males as compared to NP fish before the start of the PGD period, although this was followed by a decrease in Fsh levels and a subsequent recovery, coinciding with the reproductive season (February). Results showed that the total variance associated with the appearance of precocity may be explained by the contribution of factors such as body size and plasma levels of Igf-1, Fsh and sex steroids in male sea bass. Expression of igfs was high during stage I, and this was significantly correlated with the expression of genes related to cell cycle progression, including sox17 , scf and nf2. Finally, the decreased expression of all these gonadal factors in precocious animals suggests their potential involvement in regulating the proliferative growth of spermatogonia and supporting cells during the early stages of spermatogenesis, thus evoking the onset of puberty in male sea bass. • Igf-1 and Fsh plasma levels are indicators of early puberty in juvenile male sea bass. • The igf/igfr system shows differential gene expression, depending on the testicular stage. • Gonadal expression of igfs is positively correlated with proliferation-related genes. • igfs , sox17 , scf and nf2 are involved in spermatogenesis progression in sea bass. [ABSTRACT FROM AUTHOR]

The global expansion of shrimp aquaculture has positioned this sector as a significant contributor to seafood supply. Efficient production hinges on effective feeding management. This study presents Python-based computational tools for the acoustic monitoring of white shrimp (Penaeus vannamei) feeding activities. We compare the proposed Python implementation for automatic detection of shrimp feeding sounds with a reference detection method using Raven Pro®, examining various shrimp sizes and stocking densities. Our comparative analysis shows substantial agreement between the two methods, particularly for shrimp weighing more than 1 g across different density groups. Although Raven Pro® is a well-established bioacoustic software tested under laboratory conditions, the Python-based methods proposed here offer practical applications in real farming scenarios and can be integrated into dedicated hardware. These techniques not only enhance feeding practices but also demonstrate the potential of computational tools in advancing aquaculture management. • A Python method for detection of shrimp acoustic feeding activity is presented. • The proposed method was compared with a reference detector of Raven Pro®. • An agreement was found between click detectors across shrimp sizes and densities. • Python-based detector enables computation in resource-limited aquaculture settings. [ABSTRACT FROM AUTHOR]

Gammarus aequicauda (Amphpoda) is one of the most promising gammarid species for hypersaline aquaculture. Its population was studied in a hypersaline lake located in Crimea with field sampling from 2019 to 2023, as well as in different laboratory experiments. Here, the COI fragment s was sequenced in two color morphs (gray and pink), and two unique COI haplotypes independent of the morph were found. They belong to MOTU3 according to the classification of Hupalo et al., 2019, which is entirely consistent with this genetic group being distributed along the coasts of the Black and Azov Seas. The distribution of G. aequicauda in the lake has never been uniform; significantly higher concentrations were observed in the thickets of seagrass Ruppia , in the spring on average more than 5 times. The highest recorded abundance of this species in the lake was 89,200 m−3, and its total biomass then was 558 g m−3. In spring and summer, their numerical abundance in the Ruppia thickets was proportional to the density of Ruppia shoots and increased exponentially from March to July. The abundance of G. aequicauda observed in the lake even exceeded the values found in brackish and marine conditions. This species has three generations in Lake Moynaki during the growing season. It can be cultured at different salinities, including very successfully in 45 to 65 g L−1. It would be possible to obtain 5000 kg of its wet weight (approximately 710 kg of dry weight), per year from a hypersaline pond of 1 ha (0.01 km2). • Gammarus aequicauda (Amphipoda) is promising for aquaculture in hypersaline water. • It reaches abundance up to 89,200 m−3, and biomass of 558 g m−3 in a hypersaline lake. • The species has three generations in the hypersaline Lake Moynaki per growing season. • It is possible to obtain 5000 kg wet w per year from a hypersaline pond of 0.01 km2. • Its biomass is a good feed for shrimp, fish, hens, and other animals. [ABSTRACT FROM AUTHOR]

Over the last two decades, oyster aquaculture has largely shifted from the use of diploids to the near-exclusive use of triploids in many regions, with some hatcheries now producing >90 % triploid oyster spat. The increased demand for triploids is primarily driven by substantial growth advantages and more consistent meat quality associated with sterile triploid animals, with most data suggesting triploids and diploids display comparable adult survivorship. Although adult performance appears similar, anecdotal reports from farmers have suggested that triploids may exhibit greater frailty during earlier age classes, particularly in response to bacterial infections. Due to the extent of triploid production now taking place, the possibility of early ontogenetic frailty in triploids could pose a significant risk to oyster aquaculture production. To evaluate these claims, two cohorts of half-sibling diploid and triploid eastern oyster lines were generated in 2020 and 2021. A subset of larvae and juveniles from these lines were then exposed to a cocktail of bacterial (Vibrio) pathogens and monitored for viability. The remaining oysters were then allowed to grow for another 2 months before being deployed in either Peconic Bay, New York (2020), or Patuxent River, Maryland (2021), where their survivorship was followed for another year. Results showed that triploids were at significantly greater risk of mortality during the larvae and juvenile stages, though differential mortality decreased with age. These trends were consistent across the two spawning events, and the extent of early ontogenetic triploid frailty was observed to vary between the lines tested. This work provides valuable data for hatchery managers and farmers alike and suggests areas where specific attention and further work are required. • Triploids were more vulnerable to pathogens during hatchery stages. • Differential mortality ceased once deployed in the field. • Results were consistent across disparate spawns. • Certain lines appear to be more susceptible to early ontogenetic triploid frailty. • Larvae and juvenile results significantly corelate with one another. [ABSTRACT FROM AUTHOR]

The global mussel aquaculture industry is constrained by the unreliable supply of wild seed mussels and high losses of seed mussels shortly after they are seeded onto coastal farms. The success in the collection of the settling larvae of mussel in the wild and the subsequent on-growing of early seed mussels in aquaculture are largely determined by the settlement and attachment behaviour of the larval and juvenile mussels, which is strongly influenced by the physical structure of their attachment substrata, especially filamentous substrata. This study aimed to identify an ideal set of morphological characteristics of filamentous substrata that would promote the improved attachment of early mussels and contribute to reducing the shortage of seed mussels in the New Zealand green-lipped mussel (Perna canaliculus) aquaculture industry. Artificial filamentous substrata with varying branch width and textured surfaces were tested for their ability to promote the attachment of wild juvenile mussels. The attachment of early juvenile mussels to 1.6 mm wide filamentous substrate was six times higher than their wider counterparts (i.e., 3.7, 5.6, 7.4, and 9.5 mm). There was also a higher proportion of small-size mussels (<0.99 mm shell length) on the 1.6 mm substrata. Furthermore, the filamentous substrata with regularly ridged surface contours (1 mm spacings) tended to attract more juvenile mussels. However, this preference was not consistent for small-size mussels on filaments of thinner width (i.e., 0.4, 0.8, 1.6, and 3.7 mm). Overall, the dimensions of filamentous substrates identified through this study will be valuable for improving the design of artificial substrata used in mussel aquaculture for improving its effectiveness for the attachment of seed mussels. • Juvenile mussels prefer to attach to narrower filamentous substrata (0.4–2.4 mm). • Higher fraction of small mussels (<0.99 mm) on 1.6 mm narrow filamentous substrata. • 1 mm ridge on 5.6 mm wide branch significantly increased juvenile mussel attachment. • Study results can help improve design of catching material for juvenile mussels. [ABSTRACT FROM AUTHOR]

Taiwan highly depends on food imports and has only limited arable land available as an island. Food production is projected to decrease due to climate change, while food demand is expected to increase on account of ongoing population growth. Current agriculture practices negatively affect the environment and human health, mainly by utilizing fossil fuels, chemical fertilizers, and pesticides. Hence, the development and optimization of innovative agriculture are necessary to address the adverse effects of conventional food production systems, such as nutrient pollution, to improve sustainability. Aquaponics, the combination of hydroponics and aquaculture, potentially serves as a sustainable food production method. It has become increasingly popular in recent years, as aquaponics can have a lower environmental impact than other agriculture types. Therefore, exploring the environmental impact of local aquaponic systems can contribute to food security in Taiwan. In this regard, the current study used the life cycle assessment (LCA) tool to evaluate the environmental impact of the production of fish and lettuce in an aquaponic farm in Yilan, Taiwan. From a cradle-to-farmgate perspective, two functional units, 1 kg fish and 1 kg lettuce, were investigated. The results were compared with literature studies on traditional agriculture, hydroponics, aeroponics, and aquaculture. The LCA found that aquaponics had a higher impact in almost all categories regarding lettuce production and performed comparably to other aquaculture systems, except for showcasing higher GWP and CED. However, the analysis of environmental sustainability scenarios suggested that the environmental impact could be significantly reduced for both functional units, respectively. As shown in this study, potential reductions could be achieved by replacing fertilizer with aquaponic sludge (−23 % FWE), introducing Black Soldier Fly larvae as fish feed (−11 % MWE, −14 % LU, and − 5 % WC), and integrating a solar power system (−70 % GWP, −35 % TA & FWE, and − 16 % MWE) on the greenhouse rooftop. By implementing these sustainability measures, fish production in aquaponics would outperform most aquaculture systems considered. Therefore, aquaponics represents a promising sustainable alternative to other aquaculture systems, thus potentially contributing to Taiwan's food security. • Taiwan is increasingly facing the problem of food insecurity. • Aquaponics represents an environmentally friendly alternative for local production. • LCA highlights the potential of aquaponics in particular for fish farming. • Cooling, energy, and feed are major environmental challenges of aquaponic systems. • Solar power systems can decrease the environmental impact of aquaponics. [ABSTRACT FROM AUTHOR]

Global eel production has dramatically increased over the last 30 years due to the expansion of eel farming to meet rising human food demands. More than 45 countries around the world were engaged in eel production with a total output of 277,103 tons and 2.67 billion eels traded internationally in recent decades. However the threat of disease in eel farming is much more severe compared to other aquaculture species, often causing significant economic losses. Among eel diseases, bacterial infections are considered the most severe, although parasitic, fungal, viral, and other types of pathogens also pose significant threats. Bacterial diseases are characterized by rapid onset and high infection rates, often resulting in up to 90 % losses in aquaculture eels. In this review, we provide an overview of bacterial diseases in eels, focusing on infections caused by Aeromonas , Edwardsiella , and Vibrio infections. In addition, we discuss the current prevention, control, and treatment programs of bacterial diseases in eels, including dietary interventions, pharmaceuticals, and probiotics. The review highlights the need for more in-depth research to better understand the mechanisms by which bacterial diseases in eel occurs and to develop effective prevention and treatment strategies. Finally, improved management practices and the development of new treatments will be critical to the sustainability of aquaculture and the health of farmed eel. • This review provides an overview of bacterial diseases in eels. • This review discusses the control and treatment programs of eel bacterial diseases. • The review highlights the need to better understand the mechanisms. • New treatments will be critical to the eel farmed health. [ABSTRACT FROM AUTHOR]

Aquaculture is increasingly focused on management practices that take into account animal welfare and stress reduction; hence, the demand for effective and low-cost anesthetic substances is growing, in line with the increase in aquaculture yields. The assessment of the anesthetic potential of substances is carried out through various physiological parameters, including electromyography (EMG). This technique, when applied to fish, allows a comprehensive evaluation of general anesthesia, providing evidence of efficacy and potency. When combined with other markers, such as oculomotricity, EMG can provide a full and reliable picture of general anesthesia. Thus, the objective of this study was to evaluate the association of EMG with oculomotricity as markers of anesthetic response. For this purpose, juvenile tambaqui (Colossoma macropomum) were subjected to immersion baths in three concentrations (60 mg L−1, 80 mg L−1, and 100 mg L−1) of benzocaine (BZE). All concentrations induced loss of postural reflex in a dose-dependent manner, with the 60 mg L−1 concentrations showing shorter latency. EMG revealed that the three tested concentrations of BZE resulted in a gradual decrease in muscle tone until the complete absence of dorsal muscle contraction. In the oculomotricity parameter, we observed the cessation of saccadic eye movement at all tested concentrations. This demonstrates that oculomotricity is an effective marker for determining the complete loss of postural reflex. In conclusion, the combination of EMG and oculomotricity offers a robust and effective approach to assessing the anesthetic response in fish. These findings have significant implications for the management of animal welfare in aquaculture, providing valuable and alternative tools to ensure that anesthetic procedures are carried out effectively and safely. • Electromyography confirms dose-dependent anesthesia from benzocaine in tambaqui. • The association of electromyography and oculomotricity provides a comprehensive anesthesia assessment. • Saccadic eye movements validate anesthetic depth in tambaqui. [ABSTRACT FROM AUTHOR]

Salmon farming plays an important role in the Norwegian food industry, supplying a large portion of the world's salmon. Despite its economic importance, salmon farming faces unique biological challenges impacting the health and welfare of the fish. These factors limit the growth of salmon and the full economic potential of salmon farms, highlighting the need for advanced techniques in aquaculture to enhance productivity and sustainability. A key technical challenge is the unavailability of effective monitoring tools, leading to greater difficulties assessing the condition of salmon in water compared to the assessment of the animal stock on land-based farms. To improve the observability of salmon farms, we designed and created a computer-vision based approach for salmon breathing rate estimation (SaBRE), which allows the automatic monitoring of the respiration frequency of each individual salmon in a group of fish, seamlessly covering the entire workflow from video-stream input to the final data output (end-to-end). We thoroughly evaluated the capabilities of our method in two ways. Firstly, we performed a quantitative analysis of the constituent modules of SaBRE, revealing that all modules were highly accurate, including a salmon re-identification module that achieved an accuracy of 99.51 %. Secondly, we analyzed data from a salmon experiment with SaBRE, demonstrating that our algorithm provides high-quality respiration frequency information that can be compared with other types of experimental data to infer biological relationships. For the fish in our experiment, we observed that the ranking of the respiration frequencies in individual salmon remains relatively unchanged both in the short term and over longer periods (i.e., a salmon with a high breathing rate consistently remains among those with the highest rates, regardless of changes in the environment). Furthermore, a significant negative correlation (Pearson correlation coefficients with r values between −0.61 and −0.90 and p values below 0.01) was observed between our algorithm's estimated respiration frequency and the dissolved oxygen (dO 2) content in the water. In addition, the average breathing rate of the salmon was observed to increase in response to incidents potentially causing stress. • The individual salmon breathing rate in a group of 7 can be automatically monitored. • Breathing rate increases measurably with a decrease of dO2. • Breathing rate increases measurably when objects are inserted into a tank. • The relative breathing rate between fish in a group is consistent. [ABSTRACT FROM AUTHOR]

Many aquaculture environments suffer from significant silicon deficiencies and severe heavy metal contamination, posing substantial risks to both production and safety in aquaculture. This study aimed to assess the release of silicate from rice husk ash (RHA) and its impact on phytoplankton abundance and community composition, which are key factors affecting shellfish growth and survival. Additionally, the capacity of RHA to adsorb mercury (Hg2+) was examined using different modification methods. The results demonstrated that the concentration of dissolved silicate in seawater increased with higher RHA doses, reaching a maximum of 189.77 ± 45.61 μmol L−1 in the high RHA treatment (HR) with 1.0 g L−1 of RHA. Notably, the HR treatment group exhibited a significant increase in chlorophyll-a concentration for nano-phytoplankton (2–20 μm), with an up to eightfold rise in abundance compared to the control group. Moreover, the HR treatment resulted in a maximum diatom abundance of 4217 ± 741.98 cells L−1, benefiting diatom species such as Coscinodiscus sp., Nitzschia sp., and Cyclotella sp. These findings underscore the potential of RHA as a catalyst for diatom growth, which in turn supports the growth of shellfish. Furthermore, no concentrations of mercury (Hg), lead (Pb), cadmium (Cd), arsenic (As), copper (Cu), zinc (Zn), and chromium (Cr) were detected in any of the silicate enrichment treatments, confirming the safety of the RHA. The treatment of RHA with NaOH achieved an impressive removal efficiency of Hg2+, reaching up to 97.41 ± 0.33 %. This study highlights the promising application of agricultural waste RHA as a catalyst for diatom growth and an adsorbent for heavy metals in water systems relevant to aquaculture practices. • Dissolved silicate concentration in seawater increased with increasing rice husk ash (RHA). • Diatoms abundance were significantly increased in the RHA-treated group. • Diatom species that benefitted from RHA were Coscinodiscus sp., Nitzschia sp. and Cyclotella sp. • The removal efficiency of Hg2+ was up to 97.41 ± 0.33 % in the treatment of RHA with NaOH. [ABSTRACT FROM AUTHOR]

The Chinese mitten crab also known as Eriocheir sinensis, is an economically valuable species widely farmed in China and South-East Asia. Belonging to the subphylum Crustacea, E. sinensis are good examples of catadromous species that inhabit freshwater environment but migrate to saltwater for spawning. These crabs host diverse microbial communities across all major organs including gills, hepatopancreas, gut, and hemolymph. Migration, driven by environmental changes and stress significantly influence the diversity, community compositions, and function of the crab microbiome. These symbiotic microbes play crucial roles in crab health, nutrition, taste and diseases. Despite significant research on the intestinal microbiota of E. sinensis , the microbiome associated with other organs remains unexplored. This review, aims to consolidate current knowledge on the E. sinensis microbiome, examining the dynamics, functional roles in the host, and the impact of stress on the microbiota composition. Additionally, we identify knowledge gaps and explore possible solutions to enhance and preserve beneficial microorganisms, essential for optimizing aquaculture in the host practices. This review is the first comprehensive analysis of the microbiome associated with E. sinensis across various physiological states, providing critical insights for the sustainable management of this aquaculture species. • Chinese mitten crab (Eriocheir sinensis) is an economically important species in South-East Asia. • The microbes inhabit all major organs of this crab and influence the host health. • A comprehensive review of the literature on the different roles of microbiome in Chinese mitten crabs. [ABSTRACT FROM AUTHOR]

The global increase of aquaculture production has caused an escalating demand for alternative protein feed ingredients. Agro-industrial by-products such as sunflower meal are relatively abundant and cheap, but the content of antinutritional factors and fiber in the raw products reduce nutritional value and limit the inclusion levels in the feed for nutritionally demanding species, including salmonids. Solid-state fermentation is a microbial processing method with the potential to reduce the content of fiber and antinutritional factors and improve nutritional value in plant protein raw materials. In this study, Atlantic salmon (Salmo salar) at two commercial-like fish farms were fed experimental diets containing either 5 % non-fermented sunflower meal (as a control diet), 5 % fermented sunflower meal or 10 % fermented sunflower meal. The aim was to compare the effects of fermented sunflower meal on growth performance, gut microbiota, distal intestine histology and gene expression of Atlantic salmon under different environmental conditions. The field trial lasted for 8 and 11 months in a coastal and fjord location, respectively. The findings revealed that diets with fermented sunflower meal sustained growth performance, improved intestinal health by reducing the prevalence of prominent inflammation and ectopic goblet cells, as well as down-regulated the expression of physiological pathways related to tissue damage and cell division. Additionally, 10 % fermented sunflower meal promoted the relative abundance of gut lactic acid bacteria Lactiplantibacillus and Lactobacillaceae after long-term feeding. Our results suggest that fermented sunflower meal is a suitable protein source for Atlantic salmon when included at a level of up to 10 % in the diet. • Fermented sunflower meal reduced prominent distal intestine inflammation. • Fermented sunflower meal reduced the number of distal intestine ectopic goblet cells. • Technical pellet quality was not adversely affected by fermented sunflower meal. • 10 % fermented sunflower meal supported high growth performance under field conditions. • Fish fed fermented sunflower meal had increased gut lactic acid bacteria. [ABSTRACT FROM AUTHOR]

Development of formulated feed is now a focal point in advancing the aquaculture of spiny lobster species. This study investigated the functional morphology of two spiny lobsters, Panulirus ornatus and Sagmariasus verreauxi , by analysing mouthpart morphology and mouth aperture. The analysis is focussed on determining likely feed preference based on morphology with the aim to provide knowledge for the development of formulated feeds. There is a strong correlation between the mouth aperture being approximately 4.0 and 7.5% of the carapace length of S. verreauxi and P. ornatus juvenile and adult lobsters, respectively. This finding provides knowledge for development of a species-specific tool that could be used in experimental studies to define optimal dimensions of artificial manufactured pellets in relation to the size of the lobster. Differences in mouthpart morphology through ontogeny included increase of calcification and robustness, and this is likely to reflect a different requirement in the texture (softness/hardness) of the pellet as the animals develop. Spines and setation are a prominent feature of the mouthpart morphology and differ between species and during ontogeny. Spines on maxillipeds II and III and crista dentata on maxillipeds III are likely to play an important role in holding and manipulation of feed prior to ingestion. Pellet texture may need to accommodate these differences in species and age specific mouthpart ontogeny. Ontogenetic changes in setation were found, with much richer setation proportionally to the size of mouthpart in first instar juvenile lobsters, which decreases with size increase. Furthermore, species-specific differences indicate function shifts in mouthparts with life stages. This may indicate differences in filter feeding capacity with age and between species, as reported for other decapods. This is unlikely to be of high importance in pellet feeding but may represent an avenue of investigation for first feeds in juveniles. Collectively, the differences during ontogeny and between species suggest that formulated feeds may need to be tailored to species and life stage, particularly regarding pellet dimensions and texture. • This study describes morphology and ontogeny of mouthparts and mouth aperture in spiny lobsters P. ornatus and S. verreauxi. • The correlation of lobster mouth aperture with CL can be used as a species-specific tool for pellet dimensions optimisation. • The shifts in lobster mouthparts roles at different life stages, may be the evidence of filter feeding in early juveniles. [ABSTRACT FROM AUTHOR]

Elevated temperatures and low aquatic oxygen levels are increasingly accompanying climate warming and can adversely affect the production and welfare of farmed fish. Both environmental factors and diet affect fish energetics. Still, little is known about the dietary effects on fish energetics at elevated temperatures and low aquatic oxygen levels and how that influences growth. Thus, a feeding trial was conducted to investigate the effect of two isoenergetic diets, high protein (HP, 57% crude protein and 9% total lipid) and high lipid (HL, 40% crude protein and 19% total lipid), on juvenile barramundi (Lates calcarifer , initial body mass: ∼ 3 g). Fish were acclimated for at least four weeks on the diets (three weeks at 35 °C) before measurements began (i.e.: measurements were taken between weeks four to six of the trial). Additionally, feed intake and maximum metabolic rate were tested under three levels of aquatic oxygen levels (normoxia >80, 60% and 30% air saturation). We found no significant dietary effect on feed intake, routine, maximum and postprandial peak metabolic rate. Gill ventilation rate was also unaffected by diet treatment. However, fish fed the HP diet had increased haematocrit and haemoglobin levels, improved growth rates, feed conversion ratio, and protein deposition relative to those fed the HL diet. Thus, this study demonstrated that a high protein diet enhanced key physiological traits such as oxygen-carrying capacity, potentially supporting improved juvenile barramundi growth at elevated temperatures. • Barramundi had an increased oxygen-carrying capacity when fed a high protein diet. • A high protein diet improved growth rates but not metabolic rate performance. • Acute hypoxia but not diet impacted maximum metabolic rate and feed intake at 35 °C. [ABSTRACT FROM AUTHOR]

In this study we compile and integrate data on 42 indicators to examine the social, economic, governance and environmental conditions shaping aquaculture development across 150 countries, including the top 100 aquaculture producing countries. We apply cluster analysis to identify social-ecological archetypes of aquaculture development across these indicators. We also calculate the percentage of global aquaculture production within the quartile ranges of 15 indicators of singular relevance for development. This shows how much aquaculture production is taking place in countries performing low or high on key indices. For example, we show that 85% of global aquaculture production is taking place in countries with the highest or high climate risk, 74% in countries with the lowest or low environmental performance scores, and 90% in countries with the highest or high food supply variability. Our cluster analysis identifies four distinct archetypes driven by the 42 country-level indicators, which includes: climate risk, inland water area, coastal population, seafood consumption, trade balance, governance indices and environmental performance. We characterize the four archetypes as: Archetype 1 - Emerging aquaculture producers, Archetype 2 - Limited aquatic food engagement, Archetype 3 - Developing economy aquaculture producers, Archetype 4 - Wealthy economy aquaculture producers. We discuss this complexity of factors driving each archetype with country specific examples, as well as the utility of integrated social-ecological analysis for both continued aquaculture research and development practice. • 42 country-level indicators are compiled of social and environmental factors shaping aquaculture development across 150 countries. • We conduct an archetype analysis that classifies countries into groups with similar development profiles. • We identify four archetypes: 1 - Emerging aquaculture producers, 2 - Limited aquatic food engagement, 3 - Developing economy aquaculture producers, 4 - Wealthy economy aquaculture producers. • Findings inform the governance of aquaculture in countries with different sector profiles, risks, opportunities and social-ecological conditions. • The analysis shows that diverse data are needed to fully explain the sector's development, including social science, governance indicators, environmental data and economic conditions. [ABSTRACT FROM AUTHOR]

In aquaculture, species diversification emerges as an imperative sustainable strategy, essential for mitigating both biological and financial risks. In this context, the cultivation of sea urchins has gained prominence as an emerging trend. However, its commercial viability still faces several challenges, namely limited growth performance. Integrated multi-trophic aquaculture (IMTA) represents a potentially more profitable model by integrating extractive species to mitigate ecological impacts and promote circular economy principles. The use of polychaetes in IMTA has proven effective in recycling waste from fish aquaculture production, however, their potential should be further explored in low-trophic aquaculture solutions. This study evaluated the potential of reared sea urchin biodeposits as a nutritional feed source for the polychaete Hediste diversicolor (OF Müller, 1776). H. diversicolor juveniles were fed three diets, over 50 days: sea urchin waste (SUW), fish waste (FW) and fish feed (FF). Survival, growth, and protein and fatty acid (FA) contents were assessed. Total survival was observed in all treatments except for FW (98%). Polychaetes fed SUW and FF presented similar specific growth rates. The protein level in the polychaetes fed SUW was significantly lower, reflecting the diet's composition. The FA profile of H. diversicolor was also influenced by the respective diets. The absolute content (μg mg−1 DW) and FA profile of polychaetes were significantly different among treatments, reflecting the composition of the diets. Saturated FA (SFA) represented the dominant class in the polychaetes fed with waste diets, while in FF polychaetes polyunsaturated fatty acids (PUFA) were the major group. Nevertheless, polychaetes fed the waste diets demonstrated the PUFA biosynthetic capacity of this species, showing a considerably higher proportion of essential long-chain FA, compared to diets. Overall, these preliminary results suggest, for the first time, the potential for recycling sea urchin biodeposits into a polychaete biomass with high commercial value, presenting a promising opportunity for low-trophic integrated aquaculture models. • Hediste diversicolor was fed on three experimental diets (sea urchin waste, fish waste, and fish feed). • Sea urchin waste and fish feed promoted the same growth rate in polychaetes. • Polychaetes fed on sea urchin waste exhibited a reduced protein content. • Polychaetes fed the waste diets showed a higher proportion of long-chain fatty acids, compared to diets. • This study is the first to test sea urchin waste for polychaetes, suggesting potential for a novel low-trophic IMTA design [ABSTRACT FROM AUTHOR]

Microbiomes play an essential role in promoting host health and fitness in fishes, but the factors driving variation in gut microbiomes among individuals are not fully recognized. Understanding the biological and environmental factors influencing variation in the gut microbiome in fishes is needed to link microbiome composition to host physiology and potentially design manipulations to improve rearing success in fisheries and aquaculture. In this study, we characterized the gut microbiomes of Atlantic salmon (Salmo salar), a globally important species in commercial aquaculture and recreational fishing, considering life stage, vaccination status, and hatchery origin. Microbiomes diverged between hatchery sub-adults (age-0 parrs) and wild adults, with sub-adults exhibiting higher diversity and more similar microbiome communities when compared to adults. The diversity and composition of gut microbiomes did not differ between groups of adults that were reared in two different hatcheries and sampled from the wild. We also found that oral vaccines against bacterial kidney disease (BKD) reduced gut microbial diversity within individual sub-adult salmon, driving increased differentiation of gut microbial communities among individuals. Unvaccinated sub-adults displayed a stable core gut microbiome that was greatly reduced upon vaccination for BKD. Our results suggest that life stage is an essential factor shaping the gut microbiome of Atlantic salmon, likely driven by differences in habitat and diet, and that BKD vaccination can lead to a rapid disruption of the gut microbiome. Conditions experienced in the hatchery environment appear to have a strong influence on host gut microbiomes, but differences at early life stages may be lost due to environmental factors experienced in the wild. The plasticity of the gut microbiome throughout the life of individuals may have important implications for understanding host health, with potential applications for improving the rearing and reintroduction success of the ecologically and economically important Atlantic salmon. • We assessed the gut microbiomes of Atlantic salmon that were reared in captivity, vaccinated, and released into the wild. • Life stage shapes gut microbiome diversity, likely due to differences in habitat and diet. • BKD vaccination is associated with less diverse and highly distinct gut microbiomes. • Hatchery origin did not have a strong influence on gut microbiomes. • Long-term implications of vaccination on host microbiomes and health should be considered. [ABSTRACT FROM AUTHOR]

With plenty of resources and great potential, aquaculture is the most rapidly developing food production industry in the world and fisheries are essential to its socio-economic well-being. However, aquatic animals face significant challenges due to their increased susceptibility to infectious diseases, various stresses and also the growing demand for food and supply of livelihood attributable to the upsurge of global population. The application of probiotics in aquaculture has drawn interest as a potential microbes to preserve the health and welfare of several aquatic fauna as well as to reduce the overuse of antibiotics and synthetic drugs. Probiotics Bacillus is one of the many potential microbial possibilities that can synthesize compounds having anti-microbial properties, non-toxic as well as non-pathogenic to the fish and has the ability to sporulate, which allows them to withstand extreme climatic conditions, quorum quenching properties, all of which make it a better probiotic option than the others. Bacillus can be used to enhance the feed utilization, growth, stress response, antioxidant defense, immune function, water quality, reproductive health and disease resistance of aquatic animals, all of these have been the focus of discussion of the present review. Bacillus combined with prebiotics, as synbiotics and other compounds such as medicinal herbs, polyphenols and organic acids to form synbiotic synergism has very promising role in aquaculture, but their mode of action is still under scrutiny, hence required through systematic investigation. Commercialization of the probiotic should be done to enhance the application of probiotics at the farm level more intensively, hence increased aquaculture production, but definitely there is a lacunae in the successful commercialization of the probiotic Bacillus. Paraprobiotics and postbiotic form of the Bacillus spp. have employed in the aquaculture sector to improve the general health of the aquatic organisms, but application of both the forms in fish is very rare compared to other vertebrates. Finally, this review is dealing with the application of Bacillus or combined with prebiotics, the synbiotics and in combination with other compounds like medicinal herbs, polyphenols and organic acids as well as different form like encapsulated, paraprobiotics and postbiotics to enhance the culture of aquatic fauna have been compiled in preparation for further investigation and advancement of Bacillus spp. use in the development of sustainable aquaculture. [Display omitted] • With plenty of resources and great potential, aquaculture is the most rapidly developing food production industry in the world and fisheries are essential to its socio-economic well-being. • Bacillus is one of the many potential microbial possibilities that can synthesize antimicrobial compounds, non-toxic as well as non-pathogenic and has the ability to sporulate, quorum quenching properties, all of which make it a better probiotic option than the others. • The results concentrated the recent advances of the potential role of Bacillus and/or synbiotic synergism and its different form to enhance the culture of aquatic fauna. [ABSTRACT FROM AUTHOR]