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Measuring and monitoring fish welfare in aquaculture research relies on the use of outcome- (biotic) and input-based (e.g., abiotic) welfare indicators (WIs). Incorporating behavioural auditing into this toolbox can sometimes be challenging because sourcing quantitative data is often labour intensive and it can be a time-consuming process. Digitalization of this process via the use of computer vision and artificial intelligence can help automate and streamline the procedure, help gather continuous quantitative data and help process optimisation and assist in decision-making. The tool introduced in this study (1) adapts the DeepLabCut framework, based on computer vision and machine learning, to obtain pose estimation of Atlantic salmon parr under replicated experimental conditions, (2) quantifies the spatial distribution of the fish through a toolbox of metrics inspired by the ecological concepts home range and core area, and (3) applies it to inspect behavioural variability in and around feeding. This proof of concept study demonstrates the potential of our methodology for automating the analysis of fish behaviour in relation to home range and core area, including fish detection, spatial distribution and the variations within and between tanks. The impact of feeding on these patterns is also briefly outlined, using 5 days of experimental data as a demonstrative case study. This approach can provide stakeholders with valuable information on how the fish use their rearing environment in small-scale experimental settings and can be used for the further development of technologies for measuring and monitoring the behaviour of fish in research settings in future studies. [ABSTRACT FROM AUTHOR]

The production efficiency of rotifers, representing a crucial feed for fish larvae, is a key factor determining fish production in aquaculture. Poly(butylene succinate-co-adipate) (PBSA) is a biodegradable polymer that enhances rotifer growth, but its effect on bacterial composition remains unknown. This study was aimed to investigate changes in the structure and function of actively growing bacterial communities in rotifer culture water after PBSA treatment. PBSA induced rapid changes in water quality, including elevated organic carbon levels, decreased pH, and increased in bacterial abundance and respiration, suggesting the elution of oligomers and monomers. Consequently, these conditions led to the increased prevalence of certain actively growing bacterial families, notably Alteromonadaceae and Hyphomonadaceae, compared with that in water without PBSA, which persisted throughout the experiment. Moreover, a decrease in ammonium concentrations was observed after PBSA treatment. As functions predicted using PICRUSt2 indicated that bacteria influenced by PBSA were unlikely to directly contribute to nitrogen conversion processes such as nitrification, denitrification, and nitrogen fixation, this observation was attributed to enhanced bacterial assimilation. These findings help elucidate how PBSA enhances rotifer production, highlighting the importance of considering the functional roles of the potential microbial consortium created by PBSA to optimize its use in seed production. [ABSTRACT FROM AUTHOR]

Offshore platforms have multiple applications ranging from the age-old oil and gas industry to the latest offshore wind energy, wave-tide energy or offshore fish farms. These offshore structures encounter strong forces from waves, wind and current to name a few, during their design life; out of these, the wave loads are considered to be the most severe. Thus, appropriate studies focusing on the wave–structure interaction process are required to understand these structures’ dynamics and responses. This paper presents a detailed review of the prominent literature on the wave–structure interaction studies conducted for different types of offshore platforms subjected to wave conditions ranging from regular to extreme waves. In this review article, an in-depth discussion on the experimental and numerical modelling techniques for studies involving the interaction of waves with offshore structures is brought out, including the crucial hydrodynamic aspects such as wave-induced loading, wave-slamming loads, green water, air-gap effects, seismic loadings and hydro-elasticity. The review depicts that many challenges still persist despite much work focused on understanding the wave interaction with offshore structures are present. In essence, the present work summarises the past works carried out in this domain of offshore engineering and suggests the key areas, which need further attention. [ABSTRACT FROM AUTHOR]

Metal contamination in water bodies globally poses risks to ecosystems and human health. In Pakistan, water sources are impacted by toxic metals and microbial pollutants, affecting Nile Tilapia, a widely consumed fish in Punjab. This study assessed heavy metal and microbiological contamination in Nile tilapia from the Ravi and Chenab Rivers and nearby farms (Head Muhammad Wala, Shorkot, and Rangpur). Heavy metals, including arsenic, chromium, cadmium, mercury and lead, were analyzed using Atomic Absorption Spectroscopy, Arsenic ranged lowest from 0.15 mg/kg (scales) to highest 1.38 mg/kg (Liver), while Chromium was found to be lowest 73 mg/kg in (scales) and highest 321.83 mg/kg (Liver) in Riverine Fish, whereas in farms fish As ranged lowest from 0.05 mg/kg (flesh) to highest 0.92 mg/kg (gills),while Chromium was found to be lowest 92 mg/kg in (skin) and highest 166.67 mg/kg (Liver). Riverine fish showed elevated heavy metal levels as compared to farmed fish. Moreover, Ravi River fish also showed the highest microbial loads, including total plate counts of 15,335 cfu/g, Salmonella at 373.11 cfu/25 g, and E. coli at 76.55 cfu/g, while Chenab River fish had a significantly higher coliform count (p < 0.05). These findings suggest that farmed fish are less contaminated due to reduced exposure to industrial effluents, emphasizing the need for further research on other commonly consumed fish species in high-industrial regions. [ABSTRACT FROM AUTHOR]

The editorial discusses the importance of chrono-immunonutrition in aquaculture to enhance fish health and resilience. It highlights the challenges faced by the aquaculture industry, such as sub-optimal nutrition, infectious diseases, and environmental issues, and emphasizes the need to deepen the understanding of fish metabolism and immune responses. The research focuses on alternative feed ingredients, immune modulation, and microbiota characterization to improve fish health and welfare. Additionally, the use of novel feeds and nutritional programming is explored as potential solutions to promote sustainable aquaculture practices and increase animal welfare. [Extracted from the article]

In Québec, Canada, brook charr (Salvelinus fontinalis) is the most sought-after species for recreational fisheries, which makes it economically important. To improve population monitoring and better anticipate climate change impacts on brook charr, bioenergetics models can be useful. The objective of this research was to evaluate the performance of a resident brook charr Wisconsin Energy Budget (WEB) model applied to an anadromous strain under two salinity treatments. Growth and food consumption were predicted by the model and compared to the observed values obtained after a 60 day experiment in the laboratory on fish reared in fresh or brackish water. Predictions for fish reared in fresh water better estimated growth rate and consumption than for fish reared in brackish water, for which growth was overestimated and consumption was underestimated. Overall, these results suggest that there is a difference for the WEB model's predictions depending on the salinity and that observed food consumption is predicted more accurately than growth. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the interaction of biofloc water supplementations and potential zooplankton abundance and structure in Nile tilapia Oreochromis niloticus -rearing systems on zootechnical performance and biochemical indicators. Nile tilapia juveniles (13.30 g and 9.50 cm) were randomly distributed into 18 fiberglass tanks (500 L/tank with a stocking density of 40 fish/tank) to start the feeding experiment for 60 days. Fish weights were recorded weekly to adjust the feeding rate at 3% of their biomass using a commercial diet. Compared to the control group (T0, zero biofloc water supplementation), the influence of five biofloc supplementation levels was applied as follows: 14.2, 28.4, 42.6, 56.8, and 71 g L−1 (T1, T2, T3, T4, and T5, respectively). The biofloc was prepared in an external fermentor fiberglass tank (300 L) and added to the fish tanks to keep the biofloc levels constant during the experiment. After 30 and 60 days of the experiment, the number of zooplankton was 46,501 and 24,537 Ind. L−1, respectively, which included four families (Rotifera, Copepoda, Cladocera, and free-living nematodes) with the domination of family Rotifera at 81.65% and 93.89%, respectively. The water quality indicated was within the standard values recommended for fish culture. Compared to those of the control group, the values of growth performance, whole-body biochemical composition, and blood biochemical indicators were significantly higher in biofloc groups than in the control group. Group T3 achieved the highest significant growth performance values. In comparison with the control group, T3 achieved the lowest number of cultures and the abundance of small invertebrate prey after 60 days of culture. The fish reared in groups T0 and T1 showed the highest significant urea content and the highest concentrations of liver function enzyme activities. Interestingly, compared to all groups, T3 achieved the best feed conversion ratio (FCR) value (1.68). Principal component analysis (PCA) and Pearson's correlation coefficient confidence (PCCC) clarified a close positive relationship between T0 and T3 with the total individual, Rotifera abundance, and FCR. The highest PCCC value with T0 was in group T3 (0.947). In conclusion, biofloc supplementation (42.6 g L−1) showed a sustainable clean aquadiet strategy and significantly improved Nile tilapia growth and FCR with regard to the culture of small prey invertebrates for 60 days. [ABSTRACT FROM AUTHOR]

Intoduction: With the expansion of the aquaculture industry, the need arises for scalable, reliable, and robust methods to assess fish behaviour in sea cages to guide operational management, which includes feeding optimisation and welfare assessments. Fish cage monitoring utilising either acoustic transmitters or underwater cameras is well-studied. However, the relationship between those two different measurement types seems to have not been explored, nor have they been evaluated together in one experimental site. Methods: In our 1-month study, we compared the activity of 14 sentinel fish and the artificial intelligence (AI)-inferred speed of individuals from the European seabass (Dicentrarchus labrax) sea cage population in three feeding trials. Comparisons include a maximum activity comparison using persistent peaks, fish behavioural pattern establishment and retention, and periodical behavioural patterns. Results: Our results demonstrate that under certain circumstances, both technologies are interchangeable from the perspective of persistent peaks and periodicity, but complementary when it comes to behaviour analysis such as food anticipatory behaviour (FAB). Discussion: We anticipate that our findings will stimulate advances where multiple sensor types are in use to achieve a more holistic understanding of fish behaviour in the aquaculture sector using underwater technologies. [ABSTRACT FROM AUTHOR]

This paper is a review of the co-evolution of fish and rice farming about 10,000 years ago in the early Neolithic Era in China. China is often referred to as the origin of fish farming based on an oft cited document of Fan Li (448 BC – 536 BC) about 2,500 years ago. It is the earliest account of farming common carp (Cyprinus carpio) but its origin dates back much further. Oracle bone scripts of the Shang Dynasty (1,046 BC – 1,600 BC) are the earliest written record of fish farming in ponds. Farming common carp was prohibited in the Tang Dynasty (618 AD-907 AD) because the name of the fish, Li, was the same as that of an emperor, and this possibly led to farming Chinese carps in polyculture. There were increases in temperature and rainfall at the end of the last ice age in the Yangtze River Basin during the early Neolithic Era about 8,000 BC, drivers for subsequent development. A vast freshwater environment of inland lakes and swamps developed, with wetland plants including wild rice, as well as fish, bordered by deciduous forests and semi-arid grasslands on higher land. This enabled Austroasiatic people to gather wild foods, terrestrial and aquatic nuts as well as fish and rice. A mixed economy of hunting, gathering and fishing evolved into the co- evolution of fish and rice farming. [ABSTRACT FROM AUTHOR]

AbstractThe use of mycotoxin binders in feed products is currently the most efficient method to mitigate the harmful effects of mycotoxins. The unprecedented growth of aquaculture in recent years has led to an increased use of plant-based ingredients in fish feeds, thereby raising the risk of mycotoxin exposure. This study investigates the in vitro adsorption efficiency of a tri-octahedral bentonite against aflatoxin B1 (AFB1), zearalenone (ZEN), and fumonisin B1 (FB1) in simulated gastric (pH = 1.2) and intestinal (pH = 6.8) fluids at 25 °C, the usual body temperature in aquaculture fish species. The binder was highly effective, removing over 98% of AFB1 from both media. FB1 was completely adsorbed at pH = 1.2, while its adsorption at pH = 6.8 reached a maximum of 46.3%. ZEN binding was consistent across both pH levels, ranging from 56.1% to 69.7%. Nine equilibrium isotherm functions were fitted to the experimental data to elucidate the adsorption mechanisms. A Sips model isotherm best characterized AFB1 adsorption in simulated gastric fluid, whereas that of ZEN was best described by the Freundlich model. In simulated intestinal fluid (pH = 6.8), monolayer adsorption described by the Langmuir model provided the best fit for all three mycotoxins. [ABSTRACT FROM AUTHOR]

The environmental regulation of continental fish farming in Brazil is closely linked to land occupation and use. Areas used for this activity are mostly located in permanent preservation areas (PPA), close to rivers and springs, demonstrating the necessity of regulating this activity for its compliance with public policy. Santa Catarina is a leading state in fish farming and one of the first to regulate the use of PPAs. The feasibility of a proposal for environmental compensation to regularize the use of PPAs in Santa Catarina for fish farming; was therefore, assessed. The results showed that 74% of the fish farms analyzed need to regularize the occupation of production structures in PPAs. Regarding the proposed index of compensation for use in PPAs, the environmental compensation factor (ECF), through evaluation of the individual maps and subsequent integrated evaluation, all the fish farms identified with environmental liabilities in occupation had ratios of 1:2 and 1:3, and this index is a viable alternative for environmental regularization of the activity. It was further proposed that ECF be applied to small fish farms of up to four fiscal modules and that they have a standard minimum occupancy profile in relation to the total area of the property, as assessed in the present study. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of different feeding rates on the rearing of the curimba Prochilodus lineatus under biofloc (BFT) conditions. One hundred and sixty juvenile P. lineatus with average weights and lengths of 27.33 ± 2.07 g and 13.52 ± 0.16 cm, respectively, were randomly distributed in 16 experimental units (80 L) under BFT conditions and subjected to four feeding rates: 1.0%, 3.0%, 5.0%, and 8.0% of the fish biomass, for 60 days. During the assay, water quality variables and the proximate composition of the biofloc were monitored, as well as the productive performance and hematology of fish were evaluated. Compared to fish that received the diet at a rate of 1.0% of the biomass, the final length (14.47 ± 0.43 cm), final weight (35.55 ± 3.21 g), and gain in length (1.21 ± 0.34 cm) were significantly higher than those that received 5% of the biomass, while the fish that received 5.0% and 8.0% of the biomass, weight gain, and specific growth rate were significantly higher than those that received 1.0% of the biomass. Final biomass (296.89 ± 18.30 g) was significantly greater in fish that received the diet at a rate of 8.0% of the biomass than those that received 1.0% of the biomass (198.30 ± 49.36 g). The feed conversion rate (1.74 ± 0.26) was significantly lower in fish that received the diet at a rate of 5.0% than those that received 1.0% and 3.0% of the biomass. The protein efficiency (− 10.35 ± 5.37%) decreased significantly in fish in the 1.0% of the biomass. The survival rate of fish was significantly lower in fish from the 5.0% of the biomass (66.32 ± 14.03%) than in fish that received 3.0% of the biomass (100.00 ± 0.00%). The concentration of dissolved oxygen was significantly higher in the culture water of fish that received 1.0% and 3.0% of the biomass. The amount of sedimentable solids in the water was significantly higher in the culture water of fish at 8.0% of the biomass (242.50 ± 181.18) than in the groups of 1.0% and 3.0% of the biomass, while the hardness significantly decreased in the culture water of fish that received a diet at a rate of 5.0% of the biomass. Carbon dioxide was significantly greater in the water of the 3.0% of the biomass than in the 5.0% of the biomass. Regarding the proximal composition of the bioflocs, the dry matter significantly increased in the groups that were fed with a feeding rate of 8.0% (28.58 ± 0.01%), while the lowest contents were observed in the groups that received a feeding rate of 3.0% of the biomass. Crude protein was significantly lower in the groups that received a feeding rate of 1.0% of the biomass (28.94 ± 0.01%) than in the groups of 3.0% of the biomass. Ether extract was significantly greater in the groups of 8.0% of the biomass (1.62 ± 0.00%) than in the 3.0% of the biomass. Monocytes were significantly increased in fish that received a diet at a rate of 1.0% of the biomass compared to fish from the 5.0% and 8.0% of the biomass. Neutrophils were significantly increased in fish that received a diet at a rate of 5.0% of the biomass compared to fish in the 1.0% of the biomass. Hemoglobin was significantly decreased in fish that received a diet at a rate of 1.0% of the biomass. Hematocrit was significantly decreased in fish that received a diet at a rate of 1.0% and 8.0% of the biomass compared to fish from the 3.0% of the biomass. The results suggest that the cultivation of P. lineatus under biofloc conditions could be viable. Considering the productive performance, hematology, and water quality, a feeding rate of 5.0% of the biomass proved to be adequate for the experimental conditions adopted in the study. [ABSTRACT FROM AUTHOR]

Simple Summary: Disease outbreaks due to bacterial pathogens are among the biggest challenges in the aquaculture industry, resulting in mortality, impaired growth performance, and, subsequently, loss of profit. Antibiotic treatments are commonly used to control bacterial pathogens. However, since the development of antibiotic resistance is a concern, innovative antibiotic-free solutions are needed to replace their use. The usage of formulated functional aquafeeds incorporating additives, such as phytogenic compounds, represents a key strategy for enhancing animal performance and resilience against diseases. The results of two experiments with Tilapia demonstrate that phytogenic feed additives are promising strategies to improve fish production and provide increased protection against bacterial infection, independent of the diet formulation. Pathogens and challenging conditions in fish farming are common problems that cause mortality and reduce growth performance. Phytogenic feed additives can support the immunity of fish and thereby improve performance, production, and disease resistance. Two experiments with Nile Tilapia aimed to evaluate the effects of a matrix-encapsulated phytogenic additive (Digestarom® P.E.P. MGE) in different feed formulations, which vary in the marine meal inclusion level (5% and 12.8%), on growth performance and resistance against Streptococcus agalactiae. Fish were stocked in a recirculating aquaculture tank system per experiment and were fed with diets with or without the phytogenic supplementation for 8 weeks (six replicates per group). After an intraperitoneal injection with a sterilized saline solution and bath immersion with S. agalactiae (5 × 106 CFU/mL), mortality of the fish was recorded for 20 days. Independent of the diet formulation, the supplementation with the phytogenic feed additive significantly improved the fish production; feed conversion ratio; immune response (mainly lactic acid dehydrogenase, differential blood cell counts, and the lysozyme activity in blood); and fish survival after the S. agalactiae challenge. Thus, phytogenic feed additives are promising strategies to improve Nile tilapia production by enhancing fish growth performance, health, and protection against S. agalactiae infections. [ABSTRACT FROM AUTHOR]

Simple Summary: Fishmeal is the most important protein source in marine fish compound feeds; however, the current market prices and the imbalance between supply and demand require us to reduce the use of fishmeal. Our previous research has demonstrated that it is feasible to reduce grouper protein to 45% with high-fat feeds. However, there is no study on the feeding frequency of grouper under this formulation model, and the feeding frequency is closely related to the culture cost and fish growth and development. In this experiment, four feeding frequencies (1~4 times/day) were designed and studied for growth and gut health. Conclusion: Appropriate feeding frequency can promote growth and enhance the antioxidant capacity of the fish's gut. We recommend a best feeding frequency of 2 times/day. This experiment was to investigate the effects of feeding frequency on the growth performance, body composition, and intestinal health of hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatu ♂). Fifty-six days of feeding with four different feeding frequencies (1 time/day, 2 times/day, 3 times/day, and 4 times/day) were conducted on groupers with an initial body weight of 11.51 ± 0.02 g. The results show the following: (1) Weight gain rate (WGR) and specific growth rate (SGR) of the groupers in the 1 time/day group were significantly lower than in other groups (p < 0.05). (2) Superoxide dismutase (SOD) had the lowest value in the 1 time/day group, significantly lower than the 2 times/day and 4 times/day groups, catalase showed an upward trend, and the 4 times/day group was significantly greater than the other groups (p < 0.05). The total antioxidant capacity (T-AOC) and glutathione peroxidase (GPX) activities in the 1 time/day group were significantly lower than in the other groups (p < 0.05). (3) The increase in feeding frequency led to a significant increase in the expression levels of cat and il-6 (p < 0.05). In summary, appropriate feeding frequency can promote growth and enhance the antioxidant capacity of the fish's gut. We recommend a best feeding frequency of 2 times/day. [ABSTRACT FROM AUTHOR]

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Exogenous factors such as low water temperature can be stressful and elicit negative immune system effects, especially for fish, which are ectothermic. Stress and immune responses require energy overload, which can affect the cellular redox balance, causing oxidative damage. These overall responses impair the animal's health and negatively affect fish farming. To evaluate indicators of stress, immune and antioxidant systems, and oxidative stress responses in fish during thermal challenge, the present study reduced the water temperature from 29.5 °C to 16 °C and then inoculated pacu (Piaractus mesopotamicus) with lipopolysaccharide (LPS) from Escherichia coli. Our results revealed that acute exposure to low water temperature itself increased blood glucose, impaired the serum lysozyme concentration and increased GSH-Px activity. There was an interaction effect between low temperature and LPS inoculation. After LPS inoculation, leukocytes were initially activated (3 h); glucose levels increased (3 h); GST activity initially decreased (3 h) but then increased (6 h); SOD, CAT and GSH-Px activities decreased; and lysozyme activity remained depressed in fish subjected to cold shock. The results showed that thermal and immunological challenges impaired the maintenance of leucocyte activation and compromised the pacu oxidant response. The overall response of pacu to thermal challenge indicates that the species proved to be acutely sensitive to a drop in water temperature, reducing its ability to maintain homeostasis, especially when subjected to immunological challenge. [ABSTRACT FROM AUTHOR]

This research investigates the effects of dietary supplementation with Ecobiol plus® (Bacillus amyloliquefaciens CECT5940) on the growth performance, physiological responses, oxidative stress, and immune status of Nile tilapia (Oreochromis niloticus) fingerlings revealed to Aeromonas hydrophila. A total of 525 Nile tilapia fingerlings, averaging 30.00 ± 5.00 g in initial weight, were randomly divided into four groups (control and three experimental groups), each with three replicates of 25 fish. Ecobiol plus® was integrated in the diet at concentrations of 0.0 (control), 0.1, 0.2, and 0.4 g/kg feed. Fish were fed at 3% of their biomass daily, with biweekly adjustments based on growth. The feeding trial lasted 8 weeks, followed by a 15-day challenge with Aeromonas hydrophila to evaluate immune responses and survival outcomes. The group receiving 0.4 g/kg of Ecobiol plus® exhibited the most significant improvements in growth performance, including higher weight gain, specific growth rate, and feed conversion efficiency (p < 0.05). Blood and biochemical assessments indicated increased hemoglobin, total protein, and globulin levels, reflecting improved physiological and immunological conditions. Additionally, lysozyme activity and phagocytic response were markedly enhanced, demonstrating the probiotic's immune-boosting potential. Histopathological evaluations revealed reduced gut, gills, and hepatopancreas lesions, especially in groups with higher supplementation levels. Fish in Group T4, fed with 0.4 g/kg Ecobiol plus®, achieved the best growth performance, with a final weight of 77.96 ± 5.53 g, a weight gain of 42.46 ± 3.18 g, and a specific growth rate (SGR) of 1.51%/day, compared to the control group (T1) with a final weight of 75.26 ± 3.87 g, weight gain of 35.76 ± 2.08 g, and SGR of 1.24%/day. Survival rates considerably increased in the treated groups, with T4 exhibiting the highest rate of 96.00%, followed by T2 (94.68%), T3 (92.00%), and T1 (81.32%). Additionally, the LD50 of A. hydrophila was determined to be 3 × 10⁷ CFU/mL, underscoring the protective effect of Ecobiol plus® in enhancing fish immunity and resilience against bacterial challenges. These results suggest that Ecobiol plus® can be a natural, antibiotic-free additive to strengthen growth and disease resistance in Nile tilapia. The optimal inclusion level of Ecobiol plus® is 0.4 g/kg for maximum benefit. [ABSTRACT FROM AUTHOR]

Human exposure to polycyclic aromatic hydrocarbons (PAH) is a significant public health problem that will worsen with a warming climate and increased large-scale wildfires. Here, we characterize an epigenetic memory at the cytochrome P450 1 A (CYP1A) gene in wild Fundulus heteroclitus that have adapted to chronic, extreme PAH pollution. In wild-type fish, CYP1A is highly induced by PAH. In PAH-tolerant fish, CYP1A induction is blunted. Since CYP1A metabolically activates PAH, this memory protects these fish from PAH-mediated cancer. However, PAH-tolerant fish reared in clean water recover CYP1A inducibility, indicating a non-genetic effect. We observed epigenetic control of this reversible memory of generational PAH stress in F1 PAH-tolerant embryos. We detected a bivalent domain in the CYP1A promoter enhancer comprising both activating and repressive histone post-translational modifications. Activating modifications, relative to repressive ones, showed greater increases in response to PAH in sensitive embryos, relative to tolerant, consistent with greater gene activation. PAH-tolerant adult fish showed persistent induction of CYP1A long after exposure cessation, which is consistent with defective CYP1A shutoff. These results indicate that PAH-tolerant fish have epigenetic protection against PAH-induced cancer in early life that degrades in response to continuous gene activation. [ABSTRACT FROM AUTHOR]

The importance of the gastrointestinal microbiota (GM) in health and disease is widely recognized. Although less is known in fish than in mammals, advances in molecular techniques, such as 16S rRNA sequencing, have facilitated characterization of fish GM, comprising resident autochthonous and transient allochthonous bacteria. The microbial diversity and composition are strongly influenced by diet. High-protein diets, including alternative ingredients like plant and insect proteins, modify GM, impacting beneficial bacteria e.g. Cetobacterium. Lipids affect microbial metabolism and short-chain fatty acid (SCFA) production, while excessive carbohydrates can disrupt GM balance, causing enteritis. Dietary additives, including probiotics, prebiotics, and antibiotics, effectively modulate GM. Probiotics enhance immunity and growth, prebiotics support beneficial bacteria, and antibiotics, though effective against pathogens, disrupt microbial diversity and may promote antibiotic resistance. Environmental factors, such as temperature, salinity, and pollution, significantly influence GM. Elevated temperatures and salinity shifts alter microbial composition, and pollutants introduce toxins that compromise intestinal function and microbial diversity. Stress and pathogen infections further destabilize GM, often favoring pathogenic bacteria. GM communicates with the host via metabolites such as SCFAs, bile acids, and neurotransmitters, regulating appetite, energy metabolism, immunity, and neural functions. Additionally, GM influences the immune system by interacting with epithelial cells and stimulating immune responses. Despite recent advances, further research is needed to elucidate species-specific mechanisms underlying GM-host interactions, the ecological implications of GM diversity, and its applications in aquaculture to optimize fish health and performance. [ABSTRACT FROM AUTHOR]

The present study deals with stakeholder-driven implementation of pen culture for raising of fish seed for Culture-based fisheries (CBF) in Chamta, a floodplain wetland, in Gangetic plains through polyculture of Indian Major Carps (IMCs) Labeo catla, Labeo rohita and Cirrhinus mrigala with Small Indigenous Fishes (SIFs) Labeo bata, Systomus sarana and grass carp, Ctenopharyngodon idella in co-management mode. In the first polyculture trial IMCs and minor carps were cultured in 4 High Density Poly Ethylene (HDPE) pens (0.1 ha each) at a stocking density of 25 Nos. m−3 in equal numbers for 90 days. In the second polyculture trial IMCs were cultured with grass carp at a density of 25 Nos. m−3 in 4 HDPE pens in the ratio of 1:1:1:2 for 90 days. The same set of pens was utilized for both trials during different times of the year. Net yield of 682.3 ± 20.6 kg and 413.9 ± 21.7 kg per pen was achieved through polyculture of IMCs and SIFs and polyculture and for IMCs and grass carp, respectively. The survival percentage varied with species and culture period with overall survival of 77 (IMCs + minor carps) to 85% (IMCs + grass carp). Polyculture was economically feasible with a BC ratio of 2.01 for IMC and SIFs and 1.88 for IMC and grass carp. All the seeds produced in the pens were released to the wetland as input for CBF. The study indicated the potential of grass carp fishery in macrophyte-infested wetland. The species could attain 1.5–2 kg in 6 months and up to 3–3.5 kg weight within 1 year, utilizing macrophyte resources of the wetland. SIFs S. sarana and L. bata were observed to attain maturity in pens. The study indicated pen as an economically feasible technology to boost CBF in the wetland. The cultivation of SIFs through pen culture and CBF can enhance their production while alleviating pressure on their natural populations. Integrating pen culture using diversified species will promote sustainable fisheries management in these floodplain wetlands. [ABSTRACT FROM AUTHOR]

Introduction: This study evaluates the feasibility of culturing the high-value marine fish Protonibea diacanthus in a polyculture system with Indian pompano (Trachinotus mookalee) using a marine cage culture setup. The study aims to determine growth performance, feed efficiency, and the potential of P. diacanthus as a candidate species for polyculture. Methods: Wild-caught P. diacanthus were reared in six high-density polyethylene sea cages (Inner Diameter: 6 m; Outer Diameter: 7 m; Depth: 4.5 m; Area: 28.29 m²; Volume: 127.29 m³). Two experimental groups were established: Group-1 with 90 individuals (average weight: 130.15 ± 6.39 g) and Group-2 with 90 individuals (average weight: 287.80 ± 16.90 g). Each group was divided into three cages (30 fish/cage) and reared in triplicate with T. mookalee (2,500 fish/cage, average weight: 31.12 ± 1.17 g). The fish were cultured for 148 days and fed a commercial diet (40% crude protein, 10% crude lipid). Growth indices and feed efficiency indices were analyzed, and growth of the fish was modeled using von Bertalanffy Growth Function (VBGF). Results: Growth performance indices, including total length gain, body weight gain, and specific growth rate, were significantly higher in Group-1 (P ≤ 0.05). Feed efficiency indices (feed conversion ratio, feed efficiency ratio, and protein efficiency ratio) did not differ significantly between the groups (P > 0.05). VBGF modeling estimated P. diacanthus asymptotic length (L∞) at 164.21 ± 3.58 cm, asymptotic weight (W∞) at 44,070.19 ± 2811 g, growth coefficient (K) at 0.30 ± 0.01 yr−1 and t₀ at -0.005 ± 0.02 yr. The growth performance index (ϕ') was calculated at 1.91, surpassing values reported for wild populations. Polyculture with P. diacanthus did not significantly affect the growth or feed utilization of T. mookalee (P > 0.05). Discussion and conclusion: The results indicate that P. diacanthus exhibits superior growth under marine cage culture conditions, with a high growth performance and compatibility in polyculture systems. These findings support the potential of P. diacanthus as a viable candidate for integration into commercial polyculture systems. [ABSTRACT FROM AUTHOR]

Understanding the diversity and function of fish gut microbiomes has advanced substantially, yet many aspects remain poorly understood, particularly the interplay among microbiota, host species, and environmental factors in the context of conservation. This review explores the composition and abundance of gut bacterial communities in key aquaculture fish groups—cyprinids, ictalurids (catfish), salmonids, and cichlids (tilapia)—alongside the model organism zebrafish, across diverse geographic regions. The findings highlight environmental habitats and host species as primary determinants of gut microbiome structure, offering a global perspective on these microbial communities. Across all fish groups, the phyla Firmicutes, Fusobacteria, and Proteobacteria consistently dominated, while temperate, sub-equatorial, and sub-tropical regions exhibited the highest microbiome diversity, underscoring the contribution of taxonomic and environmental factors. The gut bacterial diversity of farm-raised fish shows a significant divergence from that of wild-caught fish, reflecting the impacts of ecological and management differences. Understanding the dynamic responses of fish gut microbiota is vital for guiding conservation efforts, safeguarding aquatic biodiversity, and advancing sustainable aquaculture practices. Future research should leverage innovative techniques and integrative approaches, both experimental and theoretical, to uncover the functional roles of microbiomes and predict their responses to environmental changes. Expanding geographic and taxonomic coverage will be critical for creating a comprehensive framework to inform global aquaculture and conservation strategies. Collectively, this perspective highlights the transformative potential of microbiome research in addressing global challenges in aquaculture and conservation biology. [ABSTRACT FROM AUTHOR]

With freshwater resources becoming scarce worldwide, mariculture is a promising avenue to sustain aquaculture development, especially by incorporating brackish and saline groundwater (GW) use into fish farming. A 75-day rearing trial was conducted to evaluate fish growth, immune response, overall health, and water quality of Chelon ramada cultured in brackish GW and fed on a basal diet (BD) augmented with rosemary oil (RO) or RO + zymogen forte™ (ZF) as an anti-flatulent. Five treatments were administrated in triplicate: T1: fish-fed BD without additives (control group); T2: fish-fed BD + 0.5 g RO /kg diet; T3: fish-fed BD + 0.5 g RO and 1 g ZF /kg diet; T4: fish-fed BD + 1 g RO /kg diet; T5: fish-fed BD + 1 g RO and 1 g ZF /kg diet. Three hundred fish (8.51 ± 0.01 g/fish) were housed in 15 fiberglass tanks (1500-L tank). The results revealed significant improvements (P < 0.05) in growth performance, survival, growth hormone, and insulin-like growth factor-1. Additionally, there were decreases in the feed conversion ratio (FCR) and the levels of nitrogen by-products (NH4, NH3, and NO2) and pathogenic bacterial counts in the rearing water when fish were fed diets supplemented with RO and RO + ZF. Furthermore, significant reductions in the levels of plasma stress indicators (cortisol, creatinine, and glucose) were detected. In addition, there were significant enhancements observed in the levels of innate immune markers, such as white blood cells, total protein, albumin, and immunoglobulin. The complement system, specifically complement 3 and complement 4, also showed considerable improvements. Furthermore, there were increases in plasma heat shock proteins HSP70 and HSP90, as well as enhanced antioxidant activity. These gains were associated with healthier liver and intestines. The investigation demonstrated that adding 0.5–1 g RO / kg diet or RO + ZF to a C. ramada diet has many benefits, including reducing the levels of nitrogen by-product chemicals and pathogenic bacterial load in GW used in growth tanks. Furthermore, significant improvements were observed in the rates of growth and associated hormones, efficiency of feed utilization, blood indicators, immune function, condition of internal organs (namely the intestine and liver), and overall health of the fish. [ABSTRACT FROM AUTHOR]

ObjectiveMethodsResultsConclusionPeople working in the Norwegian fish farming industry work in a high energy environment, where there are many hazards in the daily work. An important part of mitigating hazardous situations is to keep track of the characteristics of the accidents that have already happened and to learn from these, when planning future work. The objective of this study was to strengthen the knowledge of factors and conditions influencing personnel safety in Norwegian fish farming, based on analyses of registered occupational fatalities and injuries.We gathered reported injuries and fatalities from vessels and fish farms from three different registries. Two of these are based on mandatory reporting to authorities, and one is a privately maintained registry. The accidents from the three registries are analyzed separately, and different types of characteristics are presented.The results demonstrate that fall and crush/impact are the most common types of accidents both on vessels and fish farms. Other characteristics described are the type of vessels involved and during which type of operations injuries happened. During the last 10 years, fatalities have happened mainly in relation to lifting and maintenance operations. The reported accidents are discussed in relation to the quality of accident reports, the development in the industry towards more specialized and outsourced operations, and it points to some of the major challenges that the industry faces when planning for safe working places and operations.This overview can be used in the fish farming industry as a basis for going into further details about how accident prevention should be planned. [ABSTRACT FROM AUTHOR]

The document "Reproduction and Development in Fish: Solving Bottlenecks in Modern Aquaculture" discusses the challenges and advancements in fish reproduction and larval development in the aquaculture industry. It emphasizes the importance of sustainable growth through controlling reproduction and larval rearing processes, addressing issues such as hormonal therapies, environmental factors, and broodstock nutrition. The document also highlights the need for species diversification in aquaculture to enhance resilience and sustainability, calling for continued research and innovation in the industry. Overall, it provides valuable insights into improving aquaculture practices for a more sustainable future. [Extracted from the article]

Simple Summary: Our study investigates the karyotype of a vital polyploid fish, Carassius auratus gibelio. We found 150 chromosomes with 6 nucleolar organizer regions, suggesting complex chromosomal interactions. Male and female C. gibelio show different chromosome pairings, indicating asynchronous evolution. The formation of two trivalents or two bivalents and two univalents from six NOR bearing chromosomes in male C. gibelio is considered evidence of being in the process of rediploidization. The presence of only univalents and bivalents in the oocytes of female C. gibelio indicates that their cytogenetics are more stable, suggesting that they have completed rediploidization. Our findings contribute to the understanding of the underlying mechanisms and evolutionary outcomes of this species' genome. They provide relevant insights for further exploration of the reproductive modes of polyploid organisms and breeding strategies. Carassius auratus gibelio, a significant polyploid fish in Chinese aquaculture, can reproduce through both unisexual gynogenesis and sexual reproduction. While C. gibelio is known to exhibit polyploidy throughout its lifecycle, whether the homologous pairing of chromosomes is associated with the mode of reproduction remains unclear. Our study determined its karyotype as 2n = 150, comprising 42 metacentric, 24 submetacentric, 6 subtelocentric, and 78 telocentric chromosomes. Using AgNORs, CMA3/DAPI double fluorescence staining, and FISH, we identified six nucleolar organizer regions in C. gibelio chromosomes. Female C. gibelio exhibited only univalent and bivalent configurations, while males showed a range of chromosome configurations from univalent to hexavalent. CMA3-positive sites and FISH signals in trivalents spermatocytes hint at homologous triploidization. The formation of two trivalents or two bivalents and two univalents from six NORs bearing chromosomes in male C. gibelio is considered evidence of being in the process of rediploidization. The presence of only univalents and bivalents in the oocytes of female C. gibelio indicates that their cytogenetics are more stable, suggesting that they have completed rediploidization. Asynchronous progression of polyploidization may lead to differences in reproductive patterns between male and female C. gibelio. Our results offer cytogenetic insights into the polyploidy and evolution of C. gibelio, providing foundational cytogenomics data. This study provides relevant references for revealing the distinct reproductive strategies of male and female C. gibelio: under stable conditions, gynogenesis enables rapid clonal reproduction and swift population growth, while sexual reproduction enhances the genetic diversity within the population. [ABSTRACT FROM AUTHOR]

BACKGROUND: Traditional fish sauce products rely on relatively long fermentation time and high salt concentration, resulting in inconsistent quality and health risks. Branched‐chain fatty acids (BCFAs) are associated with nutritional benefits and health‐care effects, mainly derived from food fermentation. This study aimed to screen BCFAs‐producing bacteria with high protease and aminotransferase activity as starter cultures for fish sauce fermentation. RESULTS: The low‐salt fish sauce products were obtained by co‐fermentation with three chosen strains. Trichloroacetic acid (TCA)‐soluble peptides and amino acid nitrogen concentrations were higher in the co‐fermentation group (FH group). The organoleptic evaluation showed co‐fermentation optimized flavor composition and endured with rich taste. The levels of BCFAs and branched‐chain amino acids (BCAAs) significantly increased by co‐fermentation. Volatile metabolomics analysis indicated that BCFAs, branched‐chain esters, and pyrazines were the key flavor compounds in the co‐fermented group. CONCLUSION: The co‐fermentation system with selected strains to ferment low‐salt fish sauce has the potential to increase BCFA content and improve flavor and nutrition. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This article introduces a methodology utilizing the Analytical Hierarchy Process (AHP) integrated with a Geographic Information System (GIS) to classify sub-basins within a large river basin in terms of pollution levels.The research uses data from the Haraz River basin, located in northern Iran near the Caspian Sea. The river basin under investigation comprises seven sub-basins. The primary pollution sources in this region include domestic wastewater from urban areas, effluents from fish farms, discharge from sand and gravel mines, sewage from restaurants and tourism centers, as well as land use (agriculture, forests, and rangelands). In addition to these pollution-related factors, other criteria such as basin area, river length, road network length, and slope were also considered.Using scores assigned by experts and leveraging the Expert Choice software, all sub-basins, and factors contributing to river pollution were identified. According to the findings, urban domestic wastewater was the most significant contributor to pollution in the study Basin, accounting for 42.2% of the total pollution. The sub-basins were classified according to their final weighted scores, identifying those with the highest and lowest pollution levels.The studied approach offers substantial advantages in terms of time, cost, and resource efficiency. [ABSTRACT FROM AUTHOR]

Aquaculture and tourism can both be important industries for economic development, particularly in isolated geographies endowed with natural beauty. However, spatial conflict can arise, particularly along scenic coastlines, such as that in Oban, Scotland. This area is notable for the frequent overlap between marine tours and cage culture sites, with tours passing by or near these aquaculture locations. This study aims to understand whether tourists who encounter aquaculture operations during these tours have positive attitudes toward aquaculture–tourism integration, which refers to the favourable perception and acceptance of the coexistence of aquaculture and tourism activities, and whether this exposure influences their intention to consume locally farmed aquatic products. A face-to-face survey was conducted to recruit 200 tourists who experienced marine tours in Oban, Scotland. Hierarchical cluster analysis identified three types of tourists based on tourism motivation: (1) Multiple motivations, (2) "Relaxers", and (3) "Outgoing nature enthusiasts". Among the three tourist segments, the "Relaxers" were particularly unfamiliar with the concept of farming aquatic food. In general, the majority of tourists were positive about being exposed to aquaculture during marine tours. The results of the structural equation modelling analysis indicated that attitudes towards being exposed to aquaculture during marine tours mediate the relationship between attitudes towards aquaculture and the intention to eat locally farmed aquatic food. Motivational tourism factors, socialisation, and learning positively and significantly influenced attitudes towards being exposed to aquaculture during marine tours. Compared to age, gender, education, income, and travel frequency, only tourists' dietary patterns significantly influenced behavioural intention. The findings suggest that aquaculture might serve as a potential site for social knowledge exchange, which might be crucial not only for tourism to be successful but also for promoting aquaculture's social acceptability. The results can be used to inform policymakers, marketers, and aquaculture/tourism practitioners to promote sustainable aquaculture tourism in Scotland or similar sites where tourism and aquaculture coexist. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate alternative in vivo treatment trials using natural products for ectoparasitic infestation on Nile tilapia; these two products were not previously used in the treatment of parasitic fish diseases. So, a total of 400 Oreochromis niloticus (O. niloticus) fish measured 10–15 cm in length; 350 from a fish farm in (Kafr Elsheikh and 50 from Nile River (Al Bahr Al Aazam), Egypt. The examined fishes were 10–15 ± 0.5 cm long and weighed from 45 g ± 5. The collected fish were examined for different clinical abnormalities. Each part of the fish underwent a careful microscopic examination of mucous surrounding the skin; gills and fins. Two feed supplements were used experimentally to decrease mortality and treat fish against ectoparasites (Herb-All PARA-X® and Herb-All CALM®). Total mRNA was extracted from the gills of different examined groups. Glucose; nitric oxide; cortisol as well as lysozyme activity were assessed in all groups. The gills of the examined fish were collected for histopathological examination. Only, Dactyolgyrus sp. was recovered. The intensity of the parasite was counted per microscopic field. The treated groups showed low levels of the parameters compared to the control positive group. Up-regulation of both Tumor necrosis factor-α (TNF- α) and heat shock protein 70 (hsp-70) were detected in fins, gills, and skin in the infested tilapia. The treatment and prophylaxis significantly downregulated both genes in the studied organ in a dose-dependent manner. Recorded lesions which were scored according to their severity. In conclusion; following the use of those products, fish health has been greatly improved and that is indicated by findings of immune reactions as well as histopathology. [ABSTRACT FROM AUTHOR]

ObjectiveMethodsResultsConclusionSalmon fish farming has become a major industry in Norway, increasingly dependent on contracted maritime transport and different special services. The aim of the paper was to explore work safety for contractors in Norwegian fish farming. Previous research from other industries illustrates contractors are more susceptible to time and work pressure, have more hazardous jobs, and are more accident-prone, compared to fixed employees. This study investigated whether there are special safety challenges for contractors in Norwegian salmon farming.The study was based on a digitally distributed questionnaire survey, involving 979 employed by a fish farming company and 304 contractors. Descriptive analyses were performed on how contractors experienced interaction with the fish farming companies. Bivariate analyses (chi-square tests and t-test) were applied to explore differences related to injury and near-accident exposure and efficiency demands.Related to work absence due to work-related injuries during the last 12 months, there was no significant difference between contractors (13,5%) and fixed employees (10,2%). A greater proportion of contractors (69,8%) than fixed employees (62,5%) reported that they had experienced near-accidents during the last 2 years. Of the contractors, 55% considered their work to be undervalued by the fish farming companies, 56% that the companies’ efficiency demands led to breaking of procedures, and 66% that lack of cooperation was a threat to safety. A majority trust the companies to prioritize their safety (66%) and agree they can stop an operation if safety is threatened (87%). Compared to fixed employees, contractors reported higher efficiency demands and work pressure that could go at the expense of safety, even if the differences were small.Both contractors and fixed employees report safety challenges, and contractors could be at even more risk. Contractors perform more hazardous work, report flaws in the interaction with fish farming companies, and report higher efficiency demands. The differences are still small/modest, and safety improvement measures should involve all employees. Fish farming companies should be aware of how they influence the framework conditions for contractors. [ABSTRACT FROM AUTHOR]

Automated body weight (BW) estimation of intensively reared fish is a main goal of precision fish farming that can foster efficient monitoring and management of farms. Computer vision-based systems show a rapid development and require models estimating fish BW from images. The present study aimed to evaluate BW estimation models for European seabass (Dicentrarchus labrax) of 50 to 1,000 g. To this end, 2,933 intensively reared European seabass were individually weighed and photographed to measure several morphometric traits. Traits showing strong association with BW were included in regression analyses. BW was accurately estimated by power, multiple linear and 2nd-order polynomial models (coefficient of determination R2 > 0.9820, mean absolute percentage error from 5.7 to 6.7%) with body area, standard length, and/or body height as predictors. Present results can help to develop robust software tools for computer vision-based systems and direct measurement of BW of European seabass from images. [ABSTRACT FROM AUTHOR]

ABSTRACT Potentially zoonotic Mycobacterium spp. are impacting freshwater ornamental fish in Trinidad and Tobago. Clinical cases presented at the Aquatic Animal Health Unit of The University of the West Indies, School of Veterinary Medicine, from September 2011 to September 2018 indicated the presence of piscine mycobacteriosis in freshwater ornamental fish from locations throughout Trinidad and Tobago. Subsequently, an investigation was conducted from June 2018 to December 2021 to identify the specific Mycobacterium spp. involved. Nested polymerase chain reaction (PCR) was used to amplify and later sequence the 723 bp of the rpoB. Analysis of region V of the rpoB offers similar discriminatory power as concatenation or whole genome analysis of Mycobacterium spp., and serves as an acceptable method for differentiating and discriminating between species in this genus. With respect to tank‐reared freshwater ornamental fish, this study identified M. fortuitum (98.8% identity), M. liflandii (100% identity), M. stomatepiae (97.2% identity), M. pseudoshottsii related (96.9% identity), two M. stomatepiae related (95.4% and 96.7% identity), M. immunogenum related (93.4% identity), and 17 M. insubricum related (91.4%–95.2% identity). Additionally, seven mycobacteria related to M. insubricum were identified in wild‐caught guppies. These findings suggest that both known, and potentially novel Mycobacterium spp. are circulating, and adversely impacting the local populations of freshwater ornamental fish in Trinidad and Tobago. [ABSTRACT FROM AUTHOR]

AbstractPymetrozine (a pyridine azomethine pesticide) is one of the most commonly and frequently used insecticides. Scanty information is available about the deleterious effects of Pymetrozine on fish especially bighead carp. Hence, the current study investigated chronic toxicological effects of pymetrozine in bighead carp. A total of 80 fish were reared and divided into four groups(A–D) each containing 20 fish. Pymetrozine was given to experimental fish of groups B, C, and D mixed in water at doses of 5, 10, and 15 mg/L respectively for 30 days. Group A remained as control group. On days 10, 20, and 30 of the experiment, blood and other visceral tissues were collected for analysis of genotoxic effects, erythrocytic morphological and nuclear changes, antioxidant enzymes, and oxidative stress profile. The results revealed significantly higher values of various nuclear abnormalities (erythrocyte with micronuclei, red blood cells with condensed and lobed nuclei) and morphological changes (pear shaped erythrocyte, spindle shaped erythrocytes and spherocyte) in erythrocytes of bighead carp. The investigations on status of antioxidant enzymes and oxidative stress indicated higher values of oxidative stress biomarkers and lower values of antioxidant enzymes in visceral organs (brain, liver, gills, and kidneys) of treated fish. The findings on genotoxic potential of pymetrozine revealed a considerably increased frequency of DNA damage in isolated cells of multiple tissues (brain, liver, gills, and kidneys) of experimental fish at higher doses. In conclusion, it may be suggested that pymetrozine induces toxic effects via disruption of physiological mechanisms of multiple visceral organs of bighead carp. [ABSTRACT FROM AUTHOR]

Background: A 90-day experiment was conducted to study the impact of salinity on growth and physiological response of Pangasionodon hypophthalmus fingerling at the Brackish water fish farm of Central Institute of Fisheries Education (CIFE), Kakinada Centre, Kakinada, East Godavari District, Andhra Pradesh, India. Method: The study used different salinities condition such as 0 (control), 5 (T1), 10 (T2) and 15 (T3) ppt. Fingerlings (8.47±0.46 g) were gradually acclimatized to different salinities in 1000 l fibre reinforced plastic (FRP) tanks, in triplicates and fed with a commercial feed (crude protein 30%). Result: Growth indicators such as specific growth rate (SGR), feed conversion ratio (FCR), feed efficiency ratio (FRR) and protein efficiency ratio (PER) revealed that growth and survival were negatively affected above 10 ppt salinity. Significantly higher amylase and protease activities were observed up to 10 ppt group. In contrast, significantly higher cortisol (97.71±1.94 ng/ml) and glucose (113.32±2.66 mg/dl) levels in the blood were recorded in 15 ppt group. Overall, the study proved that P. hypophthalmus can be cultured in low saline water (up to 10 ppt) without affecting its growth and physiological homeostasis. [ABSTRACT FROM AUTHOR]

Machine learning methods, which are one of the subfields of artificial intelligence and have gained popularity in applications in recent years, play an important role in solving many challenges in aquaculture. In this study, the relationship between changes in the physico-chemical characteristics of water and feed consumption was evaluated using machine learning methods. Eleven physico-chemical characteristics (temperature, pH, dissolved oxygen, electrical conductivity, salinity, nitrite nitrogen, nitrate nitrogen, ammonium nitrogen, total phosphorus, total suspended solids, and biological oxygen demand) of water were assessed. Among all the measured physico-chemical characteristics of water, temperature was determined to be the most important parameter to be evaluated in fish feeding. Moreover, pH2, EC2, TP2, TSS2, S2 and NO2-N parameters detected in the outlet water are more important than those detected in the inlet water in terms of feed consumption. Through regression analysis carried out using machine learning methods, the models developed with Random Forest, Gradient Boosting Machine and eXtreme Gradient Boosting algorithms exhibited higher success rates in predicting feed consumption compared to the other models. The present study highlights the pivotal role of machine learning methods in enhancing our understanding of fish feeding dynamics based on physico-chemical characteristics of water, thus contributing significantly to aquaculture management practices. [ABSTRACT FROM AUTHOR]

Billions of fishes are kept in captivity for research and food production world‐wide, with a strong impetus for maintaining high welfare standards. Accordingly, the importance of empirical research into the welfare and husbandry of captive fishes is increasingly acknowledged in both science and aquaculture, alongside growing public and governmental interest. Physical enrichment can have an important influence on welfare in of captive fishes, but many questions remain. Here, we summarise the current state of research and outline knowledge gaps in the area of physical enrichment, which is a fundamental aspect to improving welfare of captive fishes. To explore the level of research interest this area across time we conducted a series of surveys, using the number of papers published per year as a metric. These surveys highlight that work on fish welfare, while representing a relatively low proportion of fish research overall, is increasing rapidly. For species that are of aquaculture importance or used commonly as laboratory subjects, we show a positive relationship between general research interest and number of welfare‐related papers. However, for many, particularly relatively less studied, species the proportion of papers on enrichment remains low, with a slower increase compared to welfare‐related papers in general. In terms of common metrics used to quantify fish welfare, there is a reliance on growth and behaviour, with scope for inclusion and combination of a more comprehensive range of reproducible measures. We finish by highlighting recent progress, promising areas for future research and suggestions for advances in this area. [ABSTRACT FROM AUTHOR]

The stress‐coping ability (SCA) is one of the core aspects of fish welfare and is of vital importance for fish production in the aquaculture industry and for fish fitness in hatchery release. Environmental enrichment (EE), a method of introducing external stimuli into the husbandry environment, has been recently proposed to improve fish SCA, but the present experimental evidence is mixed, and the reasons for these discrepancies are unclear. Here, we conducted a global meta‐analysis using a data set that consists of 1786 cases from 107 studies across 42 fish species to solve this problem. Overall, we found that enriched fish had significantly higher SCA than control fish, reflected in either basal stress levels or stress responses. Meta‐regression analyses showed that specific subgroups of enrichment type, fish developmental stage, stress category, stress duration, stress place, sample tissue and indicator system showed significant positive EE effects on SCA. Multi‐model inference indicated that the indicator system, fish developmental stage, stress characteristic and enrichment mode are important drivers for the high heterogeneity among effect sizes. These results highlight the importance of introducing EE into the rearing systems, which will not only increase the welfare of aquaculture fish but also improve the ecological adaptability of released fish. The comprehensive knowledge obtained in this analysis will provide insights into fish ontogenetic plasticity and its responses to EE and have important implications for improving the production cycle in fish aquaculture and fisheries conservation. [ABSTRACT FROM AUTHOR]

The study examined the effects of different zeolite doses on water quality parameters, fish growth performance, algae growth, and economic return from concrete ponds cultured with mono-sex male tilapia. Zeolite was used at varying doses: T1 (2.5kg/ m³), T2 (5kg/ m³), T3 (7.5kg/ m³), T4 (10kg/ m³), along with a control (Cont.: without zeolite). The results showed significant differences between the treatment groups and the control for both water quality parameters. Tilapia growth was found to be within optimal limits. The mean dissolved oxygen levels in T3 and T4 were most suitable for tilapia growth and supporting high fish production. pH levels were generally within the ideal range for tilapia. Water clarity was significantly higher in T4 compared to the control, and the addition of zeolite reduced ammonia levels while enhancing microalgae cultivation. Additionally, zeolite decreased both nitrate and nitrite levels in the water. Phosphorus removal by zeolite increased with rising pH. Zeolite significantly affected all growth indices, except the survival rate (SR) in T1. The effect of zeolite on growth and algal biomass was most pronounced in T3. The addition of zeolite significantly improved fish growth performance. While the highest weight gain (WG), average daily weight gain (ADWG), specific growth rate (SGR), and condition factor (CF) values were recorded in T4, the highest net profit percentage was achieved with T3. Based on these results, the study suggests that zeolites can enhance water quality, algal growth, fish productivity, and economic return from fish farming. [ABSTRACT FROM AUTHOR]

Environmental temperature shapes the ontogeny of ectotherms by influencing rates of growth and development which can be key determinants of survival. Whereas the escalating impacts of water management on freshwater ecosystems is well documented, the effects of cold‐water releases from dams—which can alter downstream temperatures—remains relatively underexplored but may present novel challenges to endemic ectotherms. Specifically, little is known about how thermal depressions reshape phenotypic and genetic patterns during larval metamorphosis for fishes that evolved in warmwater systems. We assessed the effects of thermal shifts on larval ontogeny of the endangered razorback sucker (Xyrauchen texanus), which evolved in the warm waters of the Colorado River Basin, USA. We hypothesised that development is more sensitive to cold‐water influences than growth and that temperature would influence patterns in gene expression related to development. Our results supported these hypotheses and showed that both wild and laboratory‐reared larvae in slightly cooler temperatures exhibited delayed development, but similar growth compared to larvae reared in warmer conditions. These findings suggest growth and development in early ectotherm life stages can be decoupled, which follows patterns more like the temperature‐size rule than allometric scaling of development by size. We also observed transcriptional differences related to genes associated with stress responses and development in our laboratory‐reared fish; here, gene expression of fish from the coldest conditions at the end of the experiment was more similar to fish reared in warmer temperatures at the midpoint. Our findings suggest that modest temperature reductions can delay ontogeny and alter the transcriptional landscape while not necessarily limiting growth. This finding highlights the need for conservation practitioners to consider cascading impacts that even small temperature reductions can cause in riverine ecosystems. [ABSTRACT FROM AUTHOR]