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Aim: Thermal sensitivity of cellular metabolism is crucial for animal physiology and survival under climate change. Despite recent efforts, effects of multigenerational exposure to temperature on the metabolic functioning remain poorly understood. We aimed at determining whether multigenerational exposure to temperature modulate the mitochondrial respiratory response of Medaka fish. Methods: We conducted a multigenerational exposure with Medaka fish reared multiple generations at 20 and 30°C (COLD and WARM fish, respectively). We then measured the oxygen consumption of tail muscle at two assay temperatures (20 and 30°C). Mitochondrial function was determined as the respiration supporting ATP synthesis (OXPHOS) and the respiration required to offset proton leak (LEAK(Omy)) in a full factorial design (COLD‐20°C; COLD‐30°C; WARM‐20°C; WARM‐30°C). Results: We found that higher OXPHOS and LEAK fluxes at 30°C compared to 20°C assay temperature. At each assay temperature, WARM fish had lower tissue oxygen fluxes than COLD fish. Interestingly, we did not find significant differences in respiratory flux when mitochondria were assessed at the rearing temperature of the fish (i.e., COLD‐20°C vs. WARM −30°C). Conclusion: The lower OXPHOS and LEAK capacities in warm fish are likely the result of the multigenerational exposure to warm temperature. This is consistent with a modulatory response of mitochondrial capacity to compensate for potential detrimental effects of warming on metabolism. Finally, the absence of significant differences in respiratory fluxes between COLD‐20°C and WARM‐30°C fish likely reflects an optimal respiration flux when organisms adapt to their thermal conditions. [ABSTRACT FROM AUTHOR]

The interest in recirculating aquaculture systems (RAS) is growing due to their benefits such as increased productivity, better control over animal care, reduced environmental effects, and less water consumption. However, in some regions of the world, traditional aquaculture methods remain prevalent, and selective breeding has often been designed for performance within these systems. Therefore, it is important to evaluate how current fish populations fare in RAS to guide future breeding choices. In a commercial setting, we explore the genetic structure of growth characteristics, measure genotype–environment interactions (GxE) in salmon smolts, and examine genetic markers related to growth in freshwater lochs and RAS. Young salmon were raised together until they reached the parr stage, after which they were divided equally between freshwater net‐pens and RAS. After an 8‐week period, we sampled fish from each environment and genotyped them. Our findings revealed that fish reared in RAS were generally smaller in weight and length but exhibited a higher condition factor and uniformity. We found a notably smaller component of unexplained variance in the RAS, leading to higher heritability estimates. We observed a low GxE effect for length and condition factor, but significant re‐ranking for whole‐body weight, as well as noticeable differences in trait associations across environments. Specifically, a segment of chromosome 22 was found to be linked with the condition factor in the RAS population only. Results suggests that if the use of RAS continues to expand, the efficiency of existing commercial populations may not reach its full potential unless breeding programs specific to RAS are implemented. [ABSTRACT FROM AUTHOR]

Southern Distinct Population Segment (sDPS) green sturgeon spawn solely in one stretch of the Sacramento River in California. Management of this spawning habitat is complicated by cold water temperature requirements for the conservation of winter-run Chinook salmon. This study assessed whether low incubation and rearing temperatures resulted in carryover effects across embryo to early juvenile life stages on scaling relationships in growth and metabolism in northern DPS green sturgeon used as a proxy for sDPS green sturgeon. Fish were incubated and reared at 11 °C and 15 °C, with a subset experiencing a reciprocal temperature transfer post-hatch, to assess recovery from cold incubation or to simulate a cold-water dam release which would chill rearing larvae. Growth and metabolic rate of embryos and larvae were measured to 118 days post hatch. Reciprocal temperature transfers revealed a greater effect of low temperature exposure during larval rearing rather than during egg incubation. While 11 °C eggs hatched at a smaller length, log-transformed length–weight relationships showed that these differences in developmental trajectory dissipated as individuals achieved juvenile morphology. However, considerable size-at-age differences persisted between rearing temperatures, with 15 °C fish requiring 60 days post-hatch to achieve 1 g in mass, whereas 11 °C fish required 120 days to achieve 1 g, resulting in fish of the same age at the completion of the experiment with a ca. 37-fold difference in weight. Consequently, our study suggests that cold rearing temperatures have far more consequential downstream effects than cold embryo incubation temperatures. Growth delays from 11 °C rearing temperatures would greatly increase the period of vulnerability to predation in larval green sturgeon. The scaling relationship between log-transformed whole-body metabolism and mass exhibited a steeper slope and thus an increased oxygen requirement with size in 11 °C reared fish, potentially indicating an energetically unsustainable situation. Understanding how cold temperatures affect green sturgeon ontogeny is necessary to refine our larval recruitment estimations for this threatened species. [ABSTRACT FROM AUTHOR]

We investigated the effects of neonicotinoid pesticides (NEOs) on the spontaneous swimming and foraging behavior, as well as the morphological and physiological changes of goldfish. Most fish reared in thiamethoxam (THM)‐sprayed rice fields showed the scales easily peeled off, and increased ascites. Some individuals showed decreased bio‐defense activity and low plasma Ca2+. Similar changes were found in the exposure test to THM (1.0 and 20.0 μg/L) and dinotefuran (1.2 and 23.5 μg/L). Next, the effects of a low concentration of THM (1.0 μg/L) on the spontaneous swimming and foraging behavior of fish were examined. Fish exposed to THM for 1 week became restless and had increased the swimming performance, especially under natural light, white LED lighting and blue LED lighting. Goldfish exposed to THM had also increased intake of shiny white beads under green LED illumination. These results indicate that the exposure to NEO, even for a short period and at low levels, not only suppressed bio‐defense activities and metabolic abnormalities, but also stress response, the swimming and foraging behavior of the fish are likely to be significantly suffered. [ABSTRACT FROM AUTHOR]

The question of whether and to what extent sea‐louse (Lepeophtheirus salmonis) infestations from salmon farms influence wild Atlantic salmon survival has been subject to sustained scientific debate and political controversy. Documenting population‐level effects of sea lice on wild salmon remains inherently challenging.We employ comprehensive sea‐lice data and recreational catch data from Norway to assess the impact of farm sea‐louse infestations on wild salmon catches in different production areas (PAs).Our analysis finds a significant correlation between declines in wild Atlantic salmon catches and increasing amounts of adult female sea lice per km2. The effect is most pronounced in PA 4 on the west coast of Norway, an area within the government's" traffic light" management system where out‐migrating salmon smolts are deemed to face high risk of louse‐induced mortality.Our model predicts below‐average catches when the total sea‐louse load exceeds the limit of 0.1 average adult female sea louse per farmed fish within some production areas. Furthermore, our results indicate that the risk of below‐average catches increases by approximately 47% when salmon farms exceed this limit (estimated risk ratio of 1.47, 95% CI [1.10, 1.96]).Synthesis and applications: Our study expands the existing body of evidence demonstrating a negative association between fish farming and the ecosystem services provided by wild salmon stocks. This has important implications for aquaculture management. First, it shows that farm sea lice directly affect peoples, rights holders and interest groups, such as landowners and anglers, who rely on viable populations of wild salmon. Second, it suggests that a >0.1 sea lice limit may be insufficient to prevent subpar catches in some areas. Furthermore, in the context of allowing further growth in farmed salmon biomass, setting absolute sea‐louse limits for entire production areas may be a more effective regulatory instrument than setting average lice limits per farmed fish. Our findings contribute to advancing a scientific basis for setting appropriate louse limits on farm and area scales. [ABSTRACT FROM AUTHOR]

The article discusses the importance of sustainable aquaculture and the development of immunonutritional approaches to enhance fish performance, health, and welfare. The special issue focuses on novel feeds and functional ingredients that can improve growth, immunity, and disease resistance in various commercially important aquatic species. The studies highlight the potential of alternative protein and lipid sources, as well as the use of bioactive compounds and probiotics, to promote fish health and reduce the need for antibiotics. Continued research and collaboration are necessary to scale up these innovations and meet the global demand for seafood while minimizing the ecological impact of aquaculture. [Extracted from the article]

Gaining insight into the diversity, structure, and metabolic functions of microbial communities is essential for understanding their roles in host health and ecosystem dynamics. However, research on the seahorse-associated microbiome remains limited, despite these threatened fish facing increasing human pressures worldwide. Here, we explored the microbial diversity and metabolic functions of the skin and gut of the tiger tail seahorse (Hippocampus comes) and its surrounding environment using shotgun metagenomics and bioinformatics. Members of the Pseudomonadota phylum were dominant in the skin microbiome, whereas Bacteroidota was dominant in the gut. Bacillota, Actinomycetota, and Planctomycetota were also detected in the seahorse-associated microbiome. Statistical analysis revealed significant differences (P < 0.01) in species diversity between skin and gut microbiomes, with members belonging to the Moraxellaceae family being dominant on the skin and the Bacteroidaceae family in the gut. Moreover, the surrounding environment (water or sediment) did not have a direct effect on the seahorse microbiome composition. The skin microbiome exhibited a higher abundance of functional genes related to energy, lipid, and amino acid metabolism as well as terpenoids and polyketides metabolism, xenobiotics biodegradation, and metabolism compared with the gut. Despite differences among classes, the total abundance of bacteriocins was similar in both gut and skin microbiomes, which is significant in shaping microbial communities due to their antimicrobial properties. A better knowledge of seahorse microbiomes benefits conservation and sustainable aquaculture efforts, offering insights into habitat protection, disease management, and optimizing aquaculture environments, thereby promoting seahorse health and welfare while minimizing environmental impact and enhancing aquaculture sustainability. NEW & NOTEWORTHY: To the best of our knowledge, this study represents the first comprehensive examination of the taxonomic and functional patterns of the skin and gut microbiome in the tiger tail seahorse. These findings have the potential to significantly enhance our understanding of the seahorse-associated microbiome, thereby contributing to the prediction and control of bacterial infections in seahorses, which are a leading cause of high mass mortality rates in seahorse aquaculture and other fish species. [ABSTRACT FROM AUTHOR]

Migratory patterns of the catfish Genidens genidens in four estuaries along the Brazilian Atlantic coast are reconstructed from otolith Sr/Ca, a salinity proxy, to test estuarine‐dependency. To facilitate interpretation of this proxy in otolith core‐to‐edge profiles, a Sr/Ca Reference Value for High Salinity (RVHSSr/Ca) of 4.88 mmol/mol was established experimentally, from fish specimens reared in water with a salinity level (33 psu) between estuarine and high salinity (marine) water. All wild specimens exhibited otolith Sr/Ca values higher than RVHSSr/Ca, suggesting that G. genidens utilizes environments with marine salinity. Our results reveal highly variable environmental histories, with at least five major habitat usage patterns. Most distinctive among these, we find that (a) fish from Paranaguá Estuarine Complex (PEC) exhibit high intraindividual heterogeneity; (b) most fish (57%) from Guanabara Bay (GB) exhibit prolonged exposure to very high salinities, often exceeding 36.5 psu levels found in some shelf sectors; and (c) some fish from Paraiba do Sul River, GB and PEC exhibit Sr/Ca values below RVHSSr/Ca consistent with estuarine residence. These results suggest that G. genidens is not strictly estuarine‐dependent. [ABSTRACT FROM AUTHOR]

Larvae of chironomids are benthic organisms, having the extreme capability to adapt to the changing physicochemical parameters of the aquatic body and the potentiality to accommodate that adverse situation. In spite of the demand for chironomid larvae as fish food, no proper technique of chironomid farming has been reported till today. This instance encourages the research on farming these larvae, in both open and captive settings. The present research shows a good result all over the year, with seasonal variance along with changing physicochemical parameters. This farming is based on minimal space requirements, reuse of condensate water, and the application of a low‐cost diet, resulting in enormous production of this insect. Thus, it can be placed as a small‐scale industry to uplift the economic status of rural people. A nutritious diet for both carnivorous and omnivorous fish and low‐cost farming with a huge production of these larvae is good for the fish industry as well. [ABSTRACT FROM AUTHOR]

As problems such as water pollution and fish species depletion have become serious, a land-based fish farming is receiving a great attention for ensuring stable productivity. In the fish farming, it is important to determine the timing of shipments, as one of key factors to increase net profit on the aquaculture. In this paper, we propose a system for predicting net profit to support decision of timing of shipment using fish farming-related statistical data. The prediction system consists of growth and farm-gate price prediction models, a cost statistics table, and a net profit estimation algorithm. The Gaussian process regression (GPR) model is exploited for weight prediction based on the analysis that represents the characteristics of the weight data of cultured fish under the assumption of Gaussian probability processes. Moreover, the long short-term memory (LSTM) model is applied considering the simple time series characteristics of the farm-gate price data. In the case of GPR model, it allows to cope with data missing problem of the weight data collected from the fish farm in the time and temperature domains. To solve the problem that the data acquired from the fish farm is aperiodic and small in amount, we generate the corresponding data by adopting a data augmentation method based on the Gaussian model. Finally, the estimation method for net profit is proposed by concatenating weight, price, and cost predictions. The performance of the proposed system is analyzed by applying the system to the Korean flounder data. [ABSTRACT FROM AUTHOR]

Objective: Surveillance fishing surveys can be performed to estimate the proportion of farmed salmon represented in the spawning stock of native Atlantic Salmon Salmo salar populations. These surveys take place after the recreational fishing period and therefore closer to the spawning period than the open recreational fishing season. Although catch‐and‐release angling has been demonstrated to affect salmon migration during the summer months, surveillance fishing that is conducted close to the spawning time could have more severe effects. Methods: To test this, the migration distance of Atlantic Salmon (n = 74) caught in the Orkla River, Norway, was tracked by use of radiotelemetry. One group was tagged during the regular fishing season in the summer (control group), whereas another group was tagged in autumn during surveillance fishing (surveillance group). Result: Sixty‐one salmon remained for analysis after we excluded fish that were recaptured, died, or migrated to other rivers. Relocation of the salmon during autumn (October 11–31) was used to compare movements and test for differences in migration using negative binomial regression because distances were nonnegative integers. During the tracking period, the surveillance group moved 12 ± 14 km (mean ± standard deviation) and the control group moved 13 ± 15 km; both groups moved 1 ± 2 km/day on average. There was no evidence that surveillance fishing impacted movement of the salmon compared to controls. However, one salmon died after tagging and three were not released due to injuries; total mortality of 9% during surveillance fishing could be unsustainable for smaller populations. Consequently, factors such as surveillance sample size, the status of the salmon population, and the population size should be assessed for each river individually when deciding the necessity of and approach to surveillance fishing. Conclusion: The results support existing recommendations to use careful handling and to end surveillance at least 2 weeks prior to the expected onset of spawning, thus providing a sufficiently long period for recovery after surveillance fishing. Impact statementSurveillance fishing is a method to determine the number of farmed salmon in a river. Capture and release of wild salmon during an autumn surveillance period may negatively impact these important spawners, but we found that movement of surveillance‐captured fish was not different from a control group. [ABSTRACT FROM AUTHOR]

Large-mouth bass originally lived in rivers and lakes and now is often raised in recirculating aquaculture systems (RAS). However, the shortcoming of RAS is that there is very limited space for swimming fish in a high-density culture environment, thus leading to a lack of exercise. To investigate the effects of exercise training on growth performance, digestive enzymes, stress, and antioxidant capacity of large-mouth bass in a RAS, three training water flow velocities with three replicates were used in the present study: low water velocity: 0.5 body length per second (bl/s) (LV); medium water velocity: 1 bl/s (MV); and high water velocity: 1.5 bl/s (HV). 270 large-mouth bass (average initial body weight 47.51 ± 1.44 g, initial body length 12.71 ± 0.06 cm) were randomly divided into nine tanks (30 fish per tank). After 27 days experiment, the results showed that the growth performance of large-mouth bass, including feed intake, weight gain rate, and specific growth rate, in the HV group was significantly higher compared to the other groups. On the physiological level, the lipase and amylase activities were significantly increased in the HV group compared to the other groups. For the stress response parameters, the cortisol, glucose and lactate concentrations in the HV group were significantly increased, which may indicate higher stress in the HV group. Regarding the antioxidant enzyme activities, the activities of catalase (CAT) and glutathione peroxidase (GSH-PX) in the LV group were significantly higher than those in the HV group, which indicated that fish suffered higher oxidative stress in the LV group. Regarding the immune-related parameters, LZM and ACP activities had no significant differences among the groups, while AKP activities in the MV and HV groups were significantly higher than that in the LV group. Overall, the results demonstrated that exercise training had significant effects on the growth, digestion, stress, and immune response of large-mouth bass. It is suggested that exercise training with 1.5 bl/s can enhance fish growth, however, it also presents a potential risk of inducing stress in fish. Therefore, in rearing largemouth bass in RAS, the setting of water flow velocity should not only focus on the growth of large-mouth bass but also consider its welfare. [ABSTRACT FROM AUTHOR]

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gymnocypris eckloni (G. eckloni), a cold-water economic fish, is widely cultivated in southwestern China. The increase in extreme summer weather conditions owing to global warming can significantly affect their survival and health. The fish intestine and its microbiota are closely associated with fish feeding and growth, nutritional metabolism, and immune defense. However, the mechanisms underlying the changes in the G. eckloni intestine and its microbiota under acute heat stress remain unknown. In this study, we investigated the effects of acute heat stress on the G. eckloni intestine employing histology, plasma biochemical indices, transcriptomics, and 16S rDNA sequencing. Histological analysis showed that acute heat stress induced significant morphological damage to the intestine, with microvilli detachment and mitochondrial abnormalities in the ultrastructure. Biochemical indicators associated with stress (reactive oxygen species and catalase), inflammation (interleukin-1b and tumor necrosis factor-a), and intestinal permeability (diamine oxidase and lipopolysaccharide) were significantly elevated after acute heat stress, indicating an intestinal inflammatory response and disruption of barrier function. Many DEGs were mined by transcriptomic analysis, with tfrc, pfkp, egln1 enriched in the HlF-1 signaling pathway, hsp70, hsp90aa1 and hspa4 enriched in the Antigen processing and presentation pathway, pmm1, pfkfb3 and hk1 enriched in the Fructose and mannose metabolism patyway. The HIF-1 signaling pathway is a crucial regulatory pathway during acute heat stress in the G. eckloni intestine, while significant downregulation of genes associated with adaptive immunity (mica, hla-dpa1, hla-dpb1, and hla-dqb2) suggested impaired immune function. Additionally, the composition of the intestinal microbiota was dominated by Aeromonas, Citrobacter, and Acinetobacter in the control group; but there was a significant decrease in the abundance of Citrobacter and Acinetobacter, and a significantly increased in Shewanella and Hafnia-Obesumbacterium after acute heat stress. Correlation analyses revealed that changes in the abundance of Hafnia-Obesumbacterium, Buttiauxella, and Pseudomonas were closely associated with changes in gene expression associated with stress, inflammation, and immunity. These results comprehensively demonstrate the adaptive mechanisms of the G. eckloni intestine in response to acutely high temperatures and provide a theoretical basis for the future advancement of artificial culture of cold-water fish. [ABSTRACT FROM AUTHOR]

This study investigated the effects of dietary supplementation with inactivated Lactobacillus plantarum for Nile tilapia (Oreochromis niloticus). Three treatments, in quintuplicate, were established: a control group, fish fed a diet without additives; LP group, fish fed a diet supplemented with live probiotic; and IP group, fish fed a diet supplemented with inactivated probiotic. Final weights (49.40 ± 3.15 g) and weight gains (38.20 ± 3.23 g) were increased in tilapia in the IP group. Feed conversion (1.32 ± 0.04) decreased significantly in the IP group. Haemato-biochemical parameters were significantly influenced by dietary supplementation. Erythrocyte count (262.74 ± 69.28 × 106 μL−1) was significantly low, while albumin (1.79 ± 1.12 g dL−1) and cholesterol (254.14 ± 98.49 mg dL−1) were high in the control group. Dietary supplementation modified the tilapia microbiome. Rhodobacter was abundant in fish intestines from the control and IP groups. Phreatobacter was abundant in the IP and LP groups, while Aurantimicrobium and Bosea were abundant in the LP group. Oleic acid (C18:1n9) was significantly increased in the LP (3.25 ± 0.49%) and IP (3.02 ± 0.30%) groups. Hexadecatrienoic acid (C16:3n4) was significantly increased (0.04 ± 0.01%) in the IP group, while Cis 11,14,17-eicosatrienoic acid (C20:3n3) (0.31 ± 0.03%) and adrenic acid (C22:4n6) (0.11 ± 0.02%) were significantly decreased in the LP group. Additionally, monounsaturated fatty acids (MUFA) were significantly increased (4.83 ± 0.35%) in the LP group compared to that in the control group. Collectively, these results indicate the potential of inactivated L. plantarum for use in commercial feed, leading to the conclusion that both inactivated and live L. plantarum can improve the Nile tilapia metabolism, altering haematological and biochemical markers. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Marine coastal resources are crucial to Tanzania's socio‐economic development and are a lifeline for the livelihoods and incomes of coastal communities. This study provides an overview of the coastal development of mariculture in mainland Tanzania and suggests future development strategies. The review article covers extensive reports available through field interviews, government policy documents, library literature searches and field work carried out by the authors. Despite the immense potential of mariculture to improve food security for localcommunities, its development has been uneven. Specifically only seaweed farming has advanced to commercial‐scale production. Other mariculture activities, such as finfish farming (e.g. milkfish, silver pompano), shellfish farming (e.g. prawn, mud crab and half‐pearl) and sea cucumber farming, are underdeveloped and confined to small‐scale operations. Locally consumed finfish, such as milkfish and pompano, have not attracted investors out of fear that the recovery of investment may not be achieved due to the low prices offered in the market. In this context, the sustainable use of coastal resources through mariculture becomes paramount to alleviating poverty and facilitating controlled migration from rural to urban. This comprehensive review explores the historical evolution and current status of mariculture initiatives in the coastal waters of mainland Tanzania, which presents a crucial aspect of the socio‐economic development of the nation. With declining global capture fisheries production and a growing demand for fish protein, Tanzania has strategically embraced mariculture as a viable alternative. The article traced the development of mariculture since the 1970s, highlighting past and current initiatives managed by government agencies, non‐government organizations and the private sector. Notable successes, such as seaweed culture, are highlighted along with the challenges that hinder the growth of marine farming activities. The review integrates insights from a comprehensive survey in coastal Tanzania, focusing on mariculture activities and collecting information on people who have stopped such practices, elucidating reasons for quitting. By consolidating experiences from past and present mariculture initiatives, this review provides valuable guidance for decision‐making towards promoting sustainable mariculture that supports coastal communities while preserving marine biodiversity. [ABSTRACT FROM AUTHOR]

Determining the most appropriate stocking density for a specific fish species in an ambient condition is essential for successful cage aquaculture in terms of profitability which is mainly governed by growth. The current study was conducted to ascertain which stocking density gives the best result of widely cultured species in cage aquaculture, pangas (Pangasianodon hypophthalmus), at swamp forest environment of Ratargul Freshwater Swamp Forest, Bangladesh in terms of growth, production and economic return. Fish were reared for 93 days at three stocking densities, namely 30, 40 and 50 fish/m3 which were denoted as FSD30, FSD40 and FSD50, respectively, containing three replications of each. Growth and yield comparisons indicated that the stocking density of fish had significant (p < 0.05) effects on growth rate and productivity. Fish cultivated at the maximum density (FSD50) had lower mean weights than fish reared at lower densities. The significantly highest mean weights (376.58 ± 14.65 g) and benefit–cost ratio (BCR) (1.617 ± 0.035) obtained from FSD30 show the suitability of this density in terms of fish growth and profitability of pangas in swamp forest environment. [ABSTRACT FROM AUTHOR]

The article presents the discussion on critical role of aquaculture in global food security, noting its substantial growth to 87.5 million tonnes, which represents nearly half of global aquatic animal production. Topics include the rapid expansion of aquaculture's share of global food production, the significant contributions of South Asia to global fish production; and the shifting dynamics from marine to inland fisheries, particularly in India and Bangladesh.

Simple Summary: In fish farming, diseases have commonly been fought with the abusive use of antibiotics, which have caused antibiotic (multi)resistances in bacteria. Consequently, it is necessary to explore safe and environmentally friendly alternative approaches to improve the fish health and avoid the treatment of bacterial diseases with antibiotics such as the use of probiotics. This study focuses on bioinformatic and functional analyses of the genome sequences of Streptococcus salivarius MDI13 and Latilactobacillus sakei MEI5, two Lactic Acid Bacteria (LAB) isolated from the gut of European hakes (Merluccius merluccius, L.), a highly valued marine fish for Spanish gastronomy. The potential probiotic characteristics of both bacteria, and the lack of antibiotic resistance genes and virulence were confirmed. In addition, genes encoding three antimicrobial peptides (known as bacteriocins) were identified in the genome of S. salivarius MDI13. One of these in vitro-synthesized bacteriocins (BlpK) showed antimicrobial activity against two fish pathogens (namely Lactococcus garvieae and Streptococcus parauberis). Altogether, our results suggest that S. salivarius MDI13 and L. sakei MEI5 have a strong potential as probiotics to prevent bacterial diseases in fish farming. Frequently, diseases in aquaculture have been fought indiscriminately with the use of antibiotics, which has led to the development and dissemination of (multiple) antibiotic resistances in bacteria. Consequently, it is necessary to look for alternative and complementary approaches to chemotheraphy that are safe for humans, animals, and the environment, such as the use of probiotics in fish farming. The objective of this work was the Whole-Genome Sequencing (WGS) and bioinformatic and functional analyses of S. salivarius MDI13 and L. sakei MEI5, two LAB strains isolated from the gut of commercial European hakes (M. merluccius, L.) caught in the Northeast Atlantic Ocean. The WGS and bioinformatic and functional analyses confirmed the lack of transferable antibiotic resistance genes, the lack of virulence and pathogenicity issues, and their potentially probiotic characteristics. Specifically, genes involved in adhesion and aggregation, vitamin biosynthesis, and amino acid metabolism were detected in both strains. In addition, genes related to lactic acid production, active metabolism, and/or adaptation to stress and adverse conditions in the host gastrointestinal tract were detected in L. sakei MEI5. Moreover, a gene cluster encoding three bacteriocins (SlvV, BlpK, and BlpE) was identified in the genome of S. salivarius MDI13. The in vitro-synthesized bacteriocin BlpK showed antimicrobial activity against the ichthyopathogens Lc. garvieae and S. parauberis. Altogether, our results suggest that S. salivarius MDI13 and L. sakei MEI5 have a strong potential as probiotics to prevent fish diseases in aquaculture as an appropriate alternative/complementary strategy to the use of antibiotics. [ABSTRACT FROM AUTHOR]

This study aims to develop a model for characterizing water quality in seawater-influenced areas for salt farming, fish farming, and crop farming. The water quality classification model was based on transfer learning trained by the Multi-Layer Perceptron Neural Network (MLPNN) and then classified by conventional Machine Learning (ML) methods, such as Decision Tree (DT), K-Nearest Neighbors (KNN), Logistic Regression (LR), Naive Bayes (NB), Random Forest (RF), and Support Vector Machine (SVM). The results of each ML classification were ensemble voted together, comparing the efficiency between hard and soft voting. The collected imbalanced dataset had a difference ratio between the majority and minority classes of 1:0.0138. However, after 900% resampling by applying the k-mean SMOTE technique, the data ratio between the majority and minority classes was 1:0.9778. The results show that the proposed ensemble approach improved accuracy by up to 2.15% in classifying water quality for salt farming, fish farming, and crop farming in seawater-influenced areas. [ABSTRACT FROM AUTHOR]

Aquaponics, defined as a sustainable technology combining aquaculture and hydroponics, integrates plant and fish production into one system. Aquaponics technology offers several major advantages over conventional methods of raising fish and/or plants. In this system, plants act as a natural biological filter, purifying the water so that the same amount can be used repeatedly. Fish, on the other hand, are a natural source of nutrients. This contributes to the aquaponics system's substantial economic potential, thanks to its use of virtually free nutrients, dramatically reduced water consumption, and the elimination of filter systems, making this system innovative and sustainable. On the other hand, the use of medicinal plants for the needs of the pharmaceutical, cosmetics, and food industries is often associated with a decrease in their natural reserves. Utilizing aquaponics for the production of medicinal plants could reduce the pressure on these natural reserves. As a result, aquaponics has emerged as one of the most environmentally friendly methods of cultivating plant species. The concept of aquaponics, which evolved from traditional hydroponic systems, has gained worldwide recognition through the effective use of symbiosis. It refers to the coexistence and interaction of different organisms, facilitating their growth and life cycle processes. Unlike hydroponics, which requires the purification of nutrient solutions due to plant waste, aquaponics takes advantage of the natural cycle of waste and nutrient exchange between plants and fish. Fish waste serves as organic fertilizer for the plants, while the plants help purify the water for the fish. This symbiotic relationship not only reduces the environmental impact associated with aquaculture wastewater but also provides a sustainable method of food production. The integrated system reduces infrastructure costs, conserves water, and minimizes the potential for environmental pollution. Furthermore, it provides an opportunity for increased profitability from both crop and fish production. Cultivation of medicinal plants within aquaponic systems can be carried out year-round, offering a continuous supply of valuable pharmacological resources. This review examines suitable medicinal plants for aquaponic cultivation and evaluates their pharmacological benefits to humans. [ABSTRACT FROM AUTHOR]

In this study early signs of deterioration of the ecosystem in the Boka Kotorska Bay were assessed by applying an active biomonitoring approach for the first time in coastal area of Montenegro. Gilthead sea bream (Sparus aurata), commercially farmed in the Bay, was used as a bioindicator. Specimens were translocated from an aquaculture farm to more impacted sites within the Bay. After two weeks of exposure, the level of DNA damage was assessed in blood cells by comet assay and micronucleus test while muscle tissues were prepared for trace element determination. The results confirmed that an active biomonitoring approach is a valuable tool for eco/geno-toxicological assessment in the marine environment. Comet assay was sensitive in discrimination of the studied groups, moreover it was sensitive enough to detect stress related to the caging procedure and translocation of animals. Lack of feeding during the exposure period was reflected on the condition index. Based on the Integrated Biomarker Response (IBR), the group exposed at the main port - Porto Montenegro was shown to be under higher environmental stress than groups exposed at reference site Dobrota (IBM) and fish farm CogiMAR. An increase in the frequency of micronuclei was evident only at this site (Porto Montenegro). Obtained trace element concentrations in fish tissues were significantly lower in comparison to values recommended by the national legislative. [ABSTRACT FROM AUTHOR]

We have investigated the changes in the microbial communities on the surface of trout eggs and the skin of adult trout in relation to the presence of Saprolegnia parasitica. This pathogen causes saprolegniosis, a disease responsible for significant losses in salmonid farms and hatcheries. It is known from other disease systems that the host-associated microbiome plays a crucial role in the defence against pathogens, but if the pathogen predominates, this can lead to dysbiosis. However, analyses of the effects of S. parasitica on the diversity, composition, and function of microbial communities on fish skin and eggs are scarce. Thus, we have collected skin swabs from injured and healthy trout (N = 12), which differed in S. parasitica load, from three different fish farms in Croatia (Kostanjevac, Radovan, and Solin), while trout egg samples (N = 12) were infected with S. parasitica in the laboratory. Illumina sequencing of the V4 region of the 16S rRNA marker gene showed that infection with S. parasitica reduced the microbial diversity on the surface of the eggs, as evidenced by decreased Pielou's evenness and Shannon's indices. We further determined whether the bacterial genera with a relative abundance of >5.0% in the egg/skin samples were present at significantly different abundances in relation to the presence of S. parasitica. The results have shown that some genera, such as Pseudomonas and Flavobacterium, decreased significantly in the presence of the pathogen on the egg surface. On the other hand, some bacterial taxa, such as Acinetobacter and Janthinobacterium, as well as Aeromonas, were more abundant on the diseased eggs and the injured trout skin, respectively. Finally, beta diversity analyses (weighted UniFrac, unweighted UniFrac, Bray–Curtis) have shown that the sampling location (i.e., fish farm), along with S. parasitica infection status, also has a significant influence on the microbial communities' composition on the trout skin and eggs, demonstrating the strong influence of the environment on the shaping of the host surface microbiome. Overall, we have shown that the presence of S. parasitica was associated with changes in the diversity and structure of the trout skin/egg microbiome. The results obtained could support the development of new strategies for the management of saprolegniosis in aquaculture. [ABSTRACT FROM AUTHOR]

Several exogenous probiotics are applicable in fish culture; however, challenges in isolation and verification have hindered the full utilization of numerous host probiotics. Therefore, this study aimed to apply the host probiotic Exiguobacterium acetylicum G1-33 to hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) cultures and explore its mechanism of action. In total, 360 hybrid grouper were divided into four groups, which were fed the following for 60 days: three received commercial feed with varying concentrations of E. acetylicum G1-33 (106, 108, and 1010 CFU/g), while a control group received commercial feed. The results showed that supplementation with 106 and 108 CFU/g of E. acetylicum G1-33 enhanced gut morphology, upregulated growth-related genes (ghr1, igf-2, s6k1, tor), and promoted growth, with supplementation with 108 CFU/g resulting in the most notable enhancement. However, supplementation with 1010 CFU/g inhibited growth, possibly because of changes in intestinal morphology. Additionally, supplementation with E. acetylicum G1-33 upregulated the expression of immune-related genes (c3, myd88, Cu/Zn-sod, tlr3, and tnf2) in the liver and head kidney but led to an increase in malondialdehyde content, as well as a decrease in alkaline phosphatase and acid phosphatase activities, in the liver and serum, indicating increased oxidative stress. Moreover, supplementation with 106 and 108 CFU/g E. acetylicum G1-33 enhanced the widespread expression of immune-related genes in the head kidney and liver, respectively, and improved resistance to Vibrio harveyi, whereas supplementation with 1010 CFU/g weakened this resistance. In conclusion, E. acetylicum G1-33, particularly at 108 CFU/g, emerged as an effective probiotic, optimizing growth performance and immunity in hybrid grouper. This research is pioneering in its application of E. acetylicum in mariculture, potentially broadening the range of probiotic strategies in aquaculture. [ABSTRACT FROM AUTHOR]

Increased interest in marine fish farming in the United States has led to a need for fundamental economic information on production of candidate species for commercialization in various production systems. Funding for the project targeted those species with potential for production in southern tier states in the United States. Sufficient technical data were found to develop comprehensive budget analyses to estimate growout production costs for four scales of production for each of 10 species with potential for production in ponds, 13 in recirculating aquaculture systems (RAS), and five in net pens. The choice of species/production system scenarios was based on evidence of successful production on farms or in research. Estimation of production costs with enterprise budgets can provide useful guidance to identify the types of improved efficiencies that have the greatest effect on economic viability even when commercial farm data are not available. Commercial farm data were used where available, but for most species, data were available only from studies conducted under research conditions. Per‐kg costs of production were lowest for net pen production, followed by ponds, with production costs in RAS two to five times greater than in ponds or net pens. Ponds and net pens generally exhibited greater efficiency of use of capital assets across species than did RAS that resulted in lower percentages of fixed costs and lower annual costs per kg of fish produced. All five species evaluated for net pen production were estimated to be profitable, including redfish, Sciaenops ocellatus (also known as red drum), striped bass, Morone saxatilis, cobia, Rachycentron canadum, red snapper, Lutjanus campechanus, and seriolids (generic budget for almaco jack, Seriola rivoliana, California yellowtail, Seriola lalandi, and greater amberjack, Seriola dumerili), four in ponds (redfish, hybrid drum, ♀Pogonias cromis × ♂Sciaenops ocellatus, black sea bass, Centropristis striata, and cobia), but none of the RAS scenarios showed profitability at average yields (kg/cubic meter) reported in the literature. Comprehensive data on growout production of marine finfish species in the United States is generally lacking, and there is a strong need for production trials conducted under near‐commercial conditions with an endpoint of market‐sized fish. Production trials should be conducted in ponds (≥0.1 ha), net pens, and RAS tanks of a size that simulate commercial production conditions. Adequate production trial databases would provide opportunities to develop economic optimization models that would provide useful guidance for prospective producers. Average yields (kg/cubic meter) in RAS will need to be much greater than currently reported in the research literature for RAS production to be economically sustainable. Net pen production appears to be profitable in the United States, but effective permitting procedures are not in place. Providing research support for the US redfish sector that has developed effective production and marketing models could serve as a foundation for developing additional species and offer opportunities for diversification on marine finfish farms. [ABSTRACT FROM AUTHOR]

The increasing frequency and duration of marine heatwaves (MHWs) due to climate change pose severe threats to aquaculture, causing drastic physiological and growth impairments in farmed fish, undermining their resilience against additional environmental pressures. To ensure sustainable production that meets the global seafood demand and animal welfare standards, cost-effective and eco-friendly strategies are urgently needed. This study explored the efficacy of the red macroalga Asparagopsis taxiformis on juvenile white seabream Diplodus sargus reared under optimal conditions and upon exposure to a MHW. Fish were fed with four experimental diets (0%, 1.5%, 3% or 6% of dried powdered A. taxiformis) for a prophylactic period of 30 days (T30) and subsequently exposed to a Mediterranean category II MHW for 15 days (T53). Biometric data and samples were collected at T30, T53 and T61 (8 days post-MHW recovery), to assess performance indicators, biomarker responses and histopathological alterations. Results showed that A. taxiformis supplementation improved catalase and glutathione S-transferase activities and reduced lipid peroxidation promoted by the MHW, particularly in fish biofortified with 1.5% inclusion level. No histopathological alterations were observed after 30 days. Additionally, fish biofortified with 1.5% A. taxiformis exhibited increased citrate synthase activity and fish supplemented with 1.5% and 3% showed improved digestive enzyme activities (e.g., pepsin and trypsin activities). Overall, the present findings pointed to 1.5% inclusion as the optimal dosage for aquafeeds biofortification with A. taxiformis, and confirmed that this seaweed species is a promising cost-effective ingredient with functional properties and great potential for usage in a climate-smart context. [ABSTRACT FROM AUTHOR]

Background. The Babon River is one of the drainage channels in Semarang, Indonesia, that is used for drinking water, irrigated agriculture of paddy fields and gardens, fish farming media, and the disposal of industrial wastewater. This study aimed to assess the spatial distribution of metals in the sediment of the Babon River through the utilization of different pollution indices. These indices included concentration factor (Cf), contamination factor (CF), enrichment factor (EF), geoaccumulation index (Igeo), sediment pollution index (SPI), threshold effect level (TEL), and probable effect level (PEL). Methods. Seven sampling locations were sampled for water and sediment in April, June, and September of 2021. The measurement of the metal was conducted using an atomic absorption spectrophotometer. Results. The findings of the study demonstrated that sediments with a predominant sand texture exhibited higher levels of Cd and Pb, while the sediments characterized by a predominant clay texture had a higher concentration of Cr. Upon analyzing the Cf, CF, EF, Igeo, and SPI data, it has been confirmed that the sediment in the Babon River has substantial levels of Cd, Cr, and Pb. According to the TEL and PEL values, it can be observed that the presence of Cd and Pb has detrimental effects on the biological health of the benthic biota. Conclusions. The aquatic biota and the benthic environment may be subject to adverse effects in the event where the concentration of metals in the sediment is higher than the natural concentration of metals. [ABSTRACT FROM AUTHOR]

EU Member States should ensure that they implement adequate health surveillance schemes in all aquaculture farming areas, as appropriate for the type of production. This study presents the results of applying the FAO's Surveillance Evaluation Tool (SET) to assess the Spanish disease surveillance system for farmed fish species, which although applied previously in livestock production, is applied here to aquaculture for the first time. Overall, there were important score differences between trout and marine fish (seabass and seabream) surveillance, which were higher for trout in the following areas: Institutional (70.8% versus 50.0%), Laboratory (91.7% versus 47.2%), and Surveillance activities (75.3% versus 61.3%). For other categories, the values were lower and no significant differences were found. However, most surveillance efforts focused only on trout, for which there are EU and WOAH listed (notifiable) diseases. In contrast, for seabream and seabass, for which there are no listed diseases, it was considered that surveillance efforts should, nevertheless, be in place and should focus on the identification of abnormal mortalities and emerging diseases, for which there are as yet no standardized harmonised methodologies. [ABSTRACT FROM AUTHOR]

The liver is essential for nutritional balance in fish, and liver damage in farmed fish often arises from factors like overfeeding, causing various health issues. Clinical observations indicate that liver diseases frequently involve spleen dysfunction, and there is evidence to suggest that the spleen has a significant impact on liver function. However, there has been no discussion on the role of the spleen in maintaining liver health in fish. To understand the role of fish spleen in liver metabolism, this study selected Nile tilapia (Oreochromis niloticus) as the experimental material and first established a tilapia splenectomy model. Various biochemical parameters of the liver and serum were measured, and the liver metabolism characteristics of the splenectomy group (SP group) and the sham operation group (SO group) were analyzed using metabolomics. After splenectomy, biochemical parameters of the liver and serum showed abnormalities, including significant increases in total cholesterol (T-CHO) and serum total bile acid (TBA) levels, alongside a significant decrease in liver TBA levels, suggesting impaired metabolic function and cholesterol deposition in the liver. Metabolomics analysis showed that metabolites such as lipids, lipid-like molecules, and organic acids and derivatives were differentially regulated between the SO and SP group. KEGG analysis showed that differential metabolites were enriched in lipid metabolism and amino acid metabolism. The metabolic pathway analysis of differential metabolites showed that after splenectomy, the low-activity urea cycle in the liver may accelerate lipid synthesis, while low concentrations of aromatic amino acids and taurine may inhibit lipid catabolism. These results indicate that after splenectomy, the liver metabolic capacity is impaired, which causes abnormal lipid metabolism by interfering with amino acid metabolism, making splenectomy tilapia liver at risk of liver disease, including cholesterol deposition, hepatic steatosis and nonalcoholic fatty liver disease (NAFLD). Our results show that the spleen is involved in regulating liver lipid and amino acid metabolism, and the spleen may interfere with lipid metabolism by regulating liver amino acid metabolism. Our data can provide support for further research on liver and spleen functions and the immune-nutrient metabolism mechanisms in fish, as well as new ideas for healthy fish farming. [ABSTRACT FROM AUTHOR]

Aquaculture, a rapidly expanding sector, meets the global surging demand for aquatic food. Pangasius, a highly valued freshwater species, has seen a significant increase in demand due to its adaptability and potential for high yields, making it a promising candidate for aquaculture in India. This study investigates the gut microbiome composition of Pangasius pangasius fish cultured in three different systems (biofloc, cage, and pond). Metagenomic DNA extraction and 16S rRNA gene-targeted sequencing were performed. Outcomes revealed distinct microbial compositions across culture types, with significant differences in species richness and diversity, specifically in the biofloc system, compared to cages and ponds. Taxonomic analysis identified prevalent phyla such as Firmicutes and Fusobacteriota, with varying abundances among culture systems. The genus-level analysis highlighted dominant genera such as Cetobacterium and WWE3. Functional profiling indicated differences in enzymatic activity and metabolic pathways, emphasizing each culture sample type's unique microbial community structures. Notably, the microbiota from BF samples exhibited significant differences and unique metabolic pathways compared to the microbiota from C and P samples, which showed greater similarity and shared several common metabolic pathways. These findings highlight substantial differences in microbial diversity across the culturing systems, reflecting the microbiota's ability to adapt to specific environments and their potential role in promoting fish growth within those environments. Overall, this study provides insights into the gut microbiome diversity and functionality in Pangasius pangasius across different aquaculture environments, contributing to a better understanding of host-microbe interactions and aquaculture management strategies. [ABSTRACT FROM AUTHOR]

Introduction: This study examines the understudied historical evolution of the seafood value chain in southern Brazil by analysing newspaper articles from Santa Catarina state, published between 1855 and 2019. Methods: Through a meticulous review of 598 selected articles, we reconstruct the development and transformation of small-scale fisheries (SSF) and their interaction with the emerging industrial fishing sector. Results and discussion: Our findings highlight the central role of SSF in the seafood value chain, contributing significantly to production, processing, retail, and trade, despite increasing competition and challenges from industrial fishing and aquaculture. The analysis reveals shifts in fish species targeted, processing methods employed, market dynamics, and consumption patterns over time. Notably, the study uncovers the resilience and adaptability of SSF in maintaining their importance to local economies and food security, amidst technological, economic, and regulatory changes. Furthermore, it underscores the often-overlooked contributions of women in seafood value chains, advocating for their equitable recognition. By providing a comprehensive and multi-faceted historical perspective, this research can inform contemporary policy-making, aiming to foster more resilient, inclusive, and sustainable seafood value chains in Brazil. [ABSTRACT FROM AUTHOR]

AbstractMagnesium oxide nanoparticles (MgO NPs) have gained significant importance in biomedicine and variety of nanotechnology-based materials used in the agriculture and biomedical industries. However, the release of different nanowastes in the water ecosystem becomes a serious concern. Therefore, this study was executed to evaluate the toxic impacts of MgO NPs on grass carp. A total of 60 grass carp were randomly divided in three groups (G0, G1, and G2). Fish reared in group G0 were kept as control while fish of groups G1 and G2 were exposed to 0.5 mg/L and 0.7 mg/L MgO NPs, respectively, mixed in water for 21 days. The 96h median lethal concentration (LC50) of MgO NPs was found to be 4.5 mg/L. Evaluation of oxidative stress biomarkers, antioxidant enzymes, DNA damage in different visceral organs and the presence of micronuclei in erythrocytes were determined on days 7, 14, and 21 of the trial. Results revealed dose- and time-dependent significantly increased values of reactive oxygen species, lipid peroxidation product, DNA damage in multiple visceral organs and formation of micronuclei in the erythrocytes of treated fish (0.7 mg/L). The results on antioxidant profile exhibited significantly lower amounts of total proteins, catalase, superoxide dismutase, and peroxidase in visceral organs of the fish exposed to MgO NPs (0.5 and 0.7 mg/L) at day 21 of trial compared to control group. In conclusion, it has been recorded that MgO NPs severely influence the normal physiological functions of the grass carp even at low doses. [ABSTRACT FROM AUTHOR]

Latin America (LATAM) plays an important role in the world's production of aquatic animals and is the second most productive region in the world. Chile, Ecuador, Brazil, Mexico, Colombia, and Perú contribute 87% of LATAM aquaculture production. The fish welfare in aquaculture is of increasing public concern globally, and LATAM is no exception, growing in importance for fish farmers, authorities, and scientists. Although the topic is somewhat controversial, the welfare status of farmed fish has direct implications for their production and the sustainability of the industry. Therefore, this study analyses scientific papers on animal welfare in farmed fish, from the six countries in LATAM with the highest aquaculture production. The main objectives were to quantify the number of papers published between 2000 and 2023 on fish welfare by using scientific databases. A total of 285 papers were found for the period analysed. The country with the largest number of publications was Brazil (75.79%), followed by Chile (13.33%), Mexico (7.02%), Peru (1.75%), Ecuador, and Colombia (1.05%). Nile tilapia was the most studied species, appearing in 30.18% of the publications, with most of the studies mainly dealing with nutrition (32.28%). The growth of aquaculture is leading to joint efforts to generate knowledge on welfare issues, especially in poorly studied species with high production, to create policies that help minimize welfare risks. Given this, the insights generated by this review could be a useful addition to approaches investigating the trends and concepts of fish welfare in LATAM. [ABSTRACT FROM AUTHOR]

Aquaculture contributes to the sustainable development of food security, marine resource conservation, and economy. Shifting aquaculture feed from fish meal and oil to terrestrial plant derivatives may result in cost savings. However, many carnivorous fish cannot be sustained on plant-derived materials, necessitating the need for the identification of important factors for farmed fish growth and the identification of whether components derived from terrestrial plants can be used in feed. Herein, we focused on the carnivorous fish leopard coral grouper (P. leopardus) to identify the essential growth factors and clarify their intake timing from feeds. Furthermore, we evaluated the functionality of starch, which are easily produced by terrestrial plants. Results reveal that carbohydrates, which are not considered essential for carnivorous fish, can be introduced as a major part of an artificial diet. The development of artificial feed using starch offers the possibility of increasing the growth of carnivorous fish in aquaculture. [ABSTRACT FROM AUTHOR]

The mangrove red snapper, Lutjanus argentimaculatus, is a marine food fish of economic and aquaculture importance. The application of genomic selection-based breeding programs for this species is limited by the absence of a reference genome and transcriptome profiles. The current study attempted to fill this void by generating genomic and transcriptomic resources for red snapper. Using PacBio long reads, and Arima Hi-C linked reads, a scaffold-level genome assembly was generated for L. argentimaculatus. The assembly is of 1.03 Gb comprising of 400 scaffolds with N50 of 33.8 Mb and was assessed to be 97.2% complete upon benchmarking with BUSCO. Full-length transcriptome generated with PacBio Iso-Sequencing strategy using six tissues (muscle, gills, liver, kidney, stomach, and gonad) contained 56,515 isoforms belonging to 18,108 unique genes with N50 length of 3,973 bp. The resources generated will have potential applications in the functional studies, conservation, broodstock management and selective breeding programmes of L. argentimaculatus. [ABSTRACT FROM AUTHOR]

Saltwater intrusion (SWI) is a critical concern affecting coastal groundwater sources due to natural and anthropogenic activities. The health of coastal aquifers is deteriorated by excessive SWI, mainly caused by the disturbance of the freshwater–saltwater equilibrium due to the escalating population, climate change, and the rising demand for freshwater resources for human activities. Therefore, gaining insight into the dynamics of SWI is crucial, particularly concerning the various factors that influence the intrusion mechanism. The present study focuses on the experimental simulation of saltwater in freshwater aquifers, considering boundary conditions and density-dependent effects. Two geological scenarios within coastal environments were investigated: First, a uniform, homogeneous case consisting of only sand, and second, a heterogeneous case in which layers of sand, clay, and sand mixed with pebbles are used. During the experiment, DC resistivity sounding data, as part of a widely recognized geophysical method, were collected and subsequently inverted to determine the depth of the freshwater–saltwater interface (FSWI). A finite element analysis was employed to generate numerical models based on experimental feedback. Further, for validation purposes, electrical resistivity tomography (ERT) data were collected from two distinct locations: near the seacoast and an aquaculture area. The ERT results show the presence of salinity intrusion in the study area, attributed mainly to groundwater overpumping and fish farming practices. The experimental findings indicate that the advancement of saltwater is affected by the geological properties of the media they traverse. The porosity (ϕ) and permeability (k) of the geological layer play a crucial role during the passage of saltwater flux into freshwater aquifers. The FSWI deviated along the clay boundary and hindered the easy passage of saltwater into surrounding layers. The alignment of experimental, numerical, and geophysical data suggests that this integrated approach could be valuable for studying SWI and can be applied in different geological settings, including tidal flats and alluvial plains. [ABSTRACT FROM AUTHOR]

Projections indicate aquaculture will produce 106 million tonnes of fish by 2030, emphasizing the need for efficient and sustainable practices. New technologies can provide a valuable tool for adequate fish farm management. The aim of this paper is to explore the factors affecting fish well-being, the design of control systems for aquaculture, and the proposal of a smart system based on algorithms to improve efficiency and sustainability. First, we identify the domains affecting fish well-being: the production domain, abiotic domain, biotic domain, and control systems domain. Then, we evaluate the interactions between elements present in each domain to evaluate the key aspects to be monitored. This is conducted for two types of fish farming facilities: cages in the sea and recirculating aquaculture systems. A total of 86 factors have been identified, of which 17 and 32 were selected to be included in monitoring systems for sea cages and recirculating aquaculture systems. Then, a series of algorithms are proposed to optimize fish farming management. We have included predefined control algorithms, energy-efficient algorithms, fault tolerance algorithms, data management algorithms, and a smart control algorithm. The smart control algorithms have been proposed considering all the aforementioned factors, and two scenarios are simulated to evaluate the benefits of the smart control algorithm. In the simulated case, the turbidity when the control algorithm is used represents 12.5% of the turbidity when not used. Their use resulted in a 35% reduction in the energy consumption of the aerator system when the smart control was implemented. [ABSTRACT FROM AUTHOR]

This study evaluated the efficacy of aqueous monovalent vaccine (AqMV) and adjuvant monovalent vaccine (AdMV), different levels of soursop leaves (SL), and turmeric rhizome (TR) on growth performance, immune response, and disease resistance of African sharptooth catfish (Clarias gariepinus) fingerlings against Pseudomonas aeruginosa. The experimental diet consists of control (without vaccine, soursop leaves and turmeric rhizome), AqMV2, AdMV3, TR4 (0.5), TR5 (1.0), TR6 (2.0), SL7 (0.5), SL8 (1.0) and SL9 (2.0). Fish were exposed to 4.85 log10 CFU/ml P. aeruginosa of 24 h old culture intraperitoneally after feeding trial with relative level of protection recorded at 28 days of post-infection. The results revealed that fish fed with treated diets showed increased (p < .05) weight gain, feed conversion ratio, nitrogen metabolism, white blood cell, globulin, total protein and blood performance and better relative level of protection compared to the control. The microbial loads in fish samples (muscle, spleen and kidney) were reduced (p < .05) in the treatments when compared to the control at 4-week post-infection. These results suggest that inactivated aqueous monovalent vaccine, soursop leaves and turmeric rhizome could be effective against P. aeruginosa infection in fish farming. [ABSTRACT FROM AUTHOR]

AbstractUnderstanding how feed intake is regulated in fish is essential for feeding efficiency in aquaculture. For this regulation, the central nervous system in fish orchestrates behavioral and physiological responses involving homeostatic and hedonic regulatory systems. Knowledge about these mechanisms in fish is variable, and this paper reviews available information following a time frame of processes occurring before, during and after feeding. Furthermore, a comprehensive understanding of feed intake regulation in fish is essential for achieving responsible aquaculture practices since regulation of feed intake goes beyond nutritional considerations, impacting growth, health, and performance. Therefore, available information about the impact on feed intake regulation of inclusion of ingredients, stressors, environmental factors, sexual dimorphism, and ontogeny are also described. [ABSTRACT FROM AUTHOR]

The interplay between environmental, biological, and physical factors often leads to the deterioration of dead fish in marine cages prior to their removal. Depending on the weight of the dead fish and the frequency of their removal, deterioration can progress to a stage where visual identification by divers becomes challenging, thereby disrupting accurate counting of dead fish. This study presents a practical precision tool for monitoring the number of dead fish during the pregrowth and growth phases of caged European sea bass (Dicentrarchus labrax). To improve the assessment of collected mortality, experiments were conducted in farming cages with various fish weights. Identifiable fish rates (I, %) were calculated every 24 hr and classified into four weight classes: WC1 (4–15 g), WC2 (15–30 g), WC3 (30–80 g), and WC4 (>80 g). The corrected number of dead fish (M) was calculated by dividing the collected number (C) by a correction factor (McR), which was determined based on the adopted removal frequency. The possible mortality removal frequencies per week (Fn) included operations such as F7 (daily), F3 (3 times), F2 (2 times), and F1 (once). The smallest correction denominator was 22% for WC1 at a frequency of once per week, whereas the maximum was 100% for WC3 and WC4 daily. The results revealed a high negative significant correlation between Fn and uncollected degraded fish rate (UR) (r = –0.841, p < 0.05). Applying corrections to mortality collected in three finished batches (B2, B3, and B7) led to an increase in the mortality rate by 3.9% ± 1.5%, 5.5% ± 0.7%, and 5.0% ± 0.5%, respectively. This explained 16.8% ± 4.7%, 65.5% ± 26.7%, and 30.3% ± 3.7% of fish disappearances in B2, B3, and B7, respectively. The significance of this study lies in its practical applicability to fish farms as a precise tool for monitoring fish raised in marine cages. [ABSTRACT FROM AUTHOR]

Background: Both bacterial and viral diseases are a major threat to farmed fish. As the antiviral immune mechanisms in lumpfish (Cyclopterus lumpus L.) are poorly understood, lumpfish leukocytes were stimulated with poly(I:C), a synthetic analog of double stranded RNA, which mimic viral infections, and RNA sequencing was performed. Methods: To address this gap, we stimulated lumpfish leukocytes with poly(I:C) for 6 and 24 hours and did RNA sequencing with three parallels per timepoint. Genome guided mapping was performed to define differentially expressed genes (DEGs). Results: Immune genes were identified, and transcriptome-wide analyses of early immune responses showed that 376 and 2372 transcripts were significantly differentially expressed 6 and 24 hours post exposure (hpe) to poly(I:C), respectively. The most enriched GO terms when time had been accounted for, were immune system processes (GO:0002376) and immune response (GO:0006955). Analysis of DEGs showed that among the most highly upregulated genes were TLRs and genes belonging to the RIG-I signaling pathway, including LGP2, STING and MX, as well as IRF3 and IL12A. RIG-I was not identified, but in silico analyses showed that genes encoding proteins involved in pathogen recognition, cell signaling, and cytokines of the TLR and RIG-I signaling pathway are mostly conserved in lumpfish when compared to mammals and other teleost species. Conclusions: Our analyses unravel the innate immune pathways playing a major role in antiviral defense in lumpfish. The information gathered can be used in comparative studies and lay the groundwork for future functional analyses of immune and pathogenicity mechanisms. Such knowledge is also necessary for the development of immunoprophylactic measures for lumpfish, which is extensively cultivated for use as cleaner fish in the aquaculture for removal of sea lice from Atlantic salmon (Salmo salar L.). [ABSTRACT FROM AUTHOR]

Introduction: Hypoxia is a recurring problem in the fish farming industry. Currently, it is known that the exposure of fish and fry to a hypoxic environment induces important changes in their metabolism, compromising not only their development but also their reproduction and mortality rates. Our hypothesis is that hypoxia constitutes one of the etiological factors causing deformation of the body and caudal fin in this species, as well as affecting its growth. Methods: We analyzed two hundred forty Salmo salar salmon fry, differentially cultured at 100% saturation (normoxia condition) and 60% (hypoxia condition) for 2, 4, 6, and 8 days, including a group under continuous hypoxia. We performed diaphanization and Alcian blue staining, along with standard histological techniques. The polyclonal anti-HIF-1a antibody was used as a marker of hypoxia in Salmo salar, and hypoxia in these fish was associated with the immunopositivity of this antibody. Results and discussion: The results indicate that there is an association between exposure to hypoxia and the deformation of the body and fin, as well as an agreement between hypoxia and the total length of the fry and fin. Several months after the event occurred, we were able to find and describe angiogenesis, blood vessel disorganization, and vasodilation histologically. Finally, hypoxic cells in the fry (HIF-1a) could be recognized and confirmed as hypoxia sensors. All of this indicates that hypoxia not only affects the fry during the development phase of the event, but that its results can be evident much later and affect the fry throughout their entire ontogeny. [ABSTRACT FROM AUTHOR]

Edwardsiellosis is a bacterial fish disease that mostly occurs in freshwater farms and is characterized by a high mortality rate. Edwardsiella tarda strain was recovered from 17 fish out of 50 Nile tilapia, which were harboring clinical signs of systemic septicemia. The level of un-ionized ammonia (NH3) in the fish farm's water was 0.11–0.15 mg/L, which was stressful for the Nile tilapia. Sequencing of the gyrB1 gene confirmed that the isolate was E. tarda JALO4, and it was submitted to NCBI under the accession number PP449014. The isolated E. tarda harbored the virulence gene edw1 AHL-synthase (quorum sensing). In addition, the isolate was sensitive to trimethoprim and sulfamethoxazole mean while it was intermediate to florfenicol. The median lethal dose (LD50) of E. tarda JALO4 was determined to be 1.7 × 105 CFU/mL in Nile tilapia. In the indoor experiment, Nile tilapia (45.05 ± 0.4 g), which received dietary Spirulina platensis (5 and 10 g/kg fish feed), showed optimum growth and feed utilization. Meanwhile, after receiving dietary S. platensis, the fish's feed conversion ratio (FCR) was significantly enhanced compared to the control, which was 1.94, 1.99, and 2.88, respectively. The expression of immune-related genes interleukin (IL)-1β and tumor necrosis factor (TNF)-α were upsurged in E. tarda-challenged fish with higher intensity in S. platensis groups. Dietary S. platensis at a dose of 10 g/kg fish feed could provide a relative protection level (RPL) of 22.2% Nile tilapia challenged against E. tarda. Nile tilapia experimentally infected E. tarda, drastically altering their behavior: higher operculum movement, low food apprehension, and abnormal swimming dietary S. platensis (10 g/kg fish feed) could rapidly restore normal status. It was concluded that Edwardsiellosis could alter Nile tilapia behavior with a high loss in fish population. Fish received dietary-S. platensis could rapidly restore normal behavior after E. tarda infection. It is recommended the incorporation of S. platensis at doses of 10 g/kg into the Nile tilapia diet to boost their immunity and counteract E. tarda infection. [ABSTRACT FROM AUTHOR]

Trichodina species can cause extensive fish mortality in an aquaculture system, and extensive use of commercial drugs affects the environment and health. The bacterial zinc nanoparticles (BZN) synthesized using Bacillus subtilis MS20 could be a suitable alternative to antiparasitic drugs. This work evaluates the antiparasitic properties of BZN against Trichodina heterodentata in Nile tilapia (Oreochromis niloticus). Furthermore, it explores BZN's effects on fish health, including growth performance, immunity, and microbial load. The BZN were 45nm in size and negatively charged at -23.6 meV. A total of 180 fish were divided into six groups. G1-G4 were non-trichodina-infected groups fed a diet supplemented with 0, 100, 200, and 500 mg/kg of BZN, the G5 was Trichodina-infected fish, and G6 was Trichodina-infected fish and treated with BZN (500 mg/kg). Fish were carefully observed for clinical alterations and mortalities. Blood and tissue samples were collected from different groups. Survival rates were 100% in the groups (G1-G4), 56.67% (G5), and 88 % (G6). The Trichodina-challenged group showed bad performance, especially in the survival rate (56 %) and body weight gain, lower erythrogram (Hb, RBCs, however, higher PCV%, which may indicate the inflammation in fish tissue), significant hypoglycemia, higher ALP activity and ammonia but lower protein content and significant increases were observed in serum amyloid A (SAA) and interleukin-6 (IL-6) values. Applying BZN 500 mg/kg to the challenged group maintains the parameters to control levels and alleviates the effect of Trichodina species infection. The histopathology of liver tissues supported the blood biochemistry results. The Trichodina-challenged fish showed extensive vacuolar degeneration of hepatocytes and massive necrosis of the pancreas hyperplastic proliferation of the epithelial lining of the secondary lamellae; meanwhile, BZN-treated groups showed normal liver and gill tissue structure. The BZN treatment significantly reduced the total bacterial count by 31-45% and Aeromonas count by 30-44%. Finally, it is concluded that using BZN 500 mg/kg significantly mitigates the Trichodina heterodentata infection in Nile Tilapia (Oreochromis niloticus) and enhances fish health. [ABSTRACT FROM AUTHOR]

The movement of live aquatic animals crossing international borders is a regular activity for economic, social, and public resource development. A survey was carried out to investigate the prevalence of parasites translocated with imported ornamental fishes. Exotic diseases from imported fish have a potential hazard of biosecurity. A sample of 138 imported ornamental fish originating from Thailand and Sri Lanka were collected from pet shops around Muscat governorate and examined for ectoparasites. Parasitological examination was based on a visual macro and microscopic examination of fish's exterior. The findings of the current survey of imported ornamental fish revealed that 50.72% of the imported ornamental fish were infected by the one or more of ectoparasites species including Ichthyophthirius multifiliis, Dactylogyrus sp., Gyrodactylus sp., digenean metacercaria and Trichodina sp. Parasitic infection of the gills (55.795) was higher than the skin (42.75%). The most prevalent parasite in skin infection was Gyrodactylus sp. (14.49%) but this was absent from the gills which was dominated by digenean metacercaria (26.08%). The existence of such parasitic organisms could pose a threat to native fish populations and the aquaculture sector. It is recommended that a risk analysis method based on the detection and assessment of fish diseases found in live ornamental fish be established and used. Also, exotic pathogenic parasites, as well as their hosts, must be closely monitored to reduce the likelihood of infections being introduced into new areas. [ABSTRACT FROM AUTHOR]

This study aims to analyze the administration of microencapsulated probiotic Bacillus cereus BR2 through feed atdifferent doses on the survival, immune response, and digestive enzyme activity of catfish Clarias sp. infected with Aeromonas hydrophila NFC1. The research design consisted of five treatments and three replications, (K-) feeding without the supplementation of probiotics fish injected with Phosphate-buffered saline solution, (K+) feeding without the supplementation of probiotics fish injected with A. hydrophila NFC1 cell suspension (106 CFU/mL), (P1) feeding with supplementation of B. cereus BR2 microcapsules at a dose of 0.5% (w/w), (P2) feeding with the supplementation of B. cereus BR2 microcapsules at a dose of 1% (w/w; (P3) feeding with the supplementation of B. cereus BR2 microcapsules at a dose of 2% (w/w). All treatments of P1, P2, and P3 were intramuscularly injected with A. hydrophila NFC1 cell suspension. Catfish in average body weight of 3.73 ± 0.22 g were reared in tanks filled with 30 liters of water, at a density of 15 fish per container. A feed supplementation trial was performed for 40 days with feeding times three times a day and a 5% feeding rate reevaluated based on biomass. Fish rearing was continued after the challenge test with A. hydrophila NFC1 for 10 days. The results showed that the application of supplemented feed containing B. cereus BR2 probiotic microcapsules increased the survival rate, immune response, and digestive enzyme activities of catfish which was infected with A. hydrophila NFC1, 2% microcapsule supplementation demonstrated the best result. [ABSTRACT FROM AUTHOR]

Infectious disease is a major challenge in fish and shrimp farming systems caused by microorganisms including bacteria, viruses and parasites. Physical detection has limitations in detecting diseases in cultivated animals earlier, because of the varied clinical symptoms. The aims of this study was to identify the physical and molecular presence of infectious pathogens in fish and shrimp cultivated in several ponds in West Java, Banten and Jakarta. Monitoring was carried out in two stages, namely the period March–April 2021 and September 2021 by taking samples from several ponds in Bogor, Tangerang, Depok and Jakarta. The sample criteria used were fish and shrimp showing normal and clinical symptoms of being attacked by a disease which were collected by purposive sampling. The collected samples were examined in two stages, namely physical examination of clinical symptoms and molecular examination using PCR. The results showed that of the 24 species samples collected, 17 species showed normal clinical symptoms and seven species showed clinical symptoms. Of the 24 fish and shrimp samples, four samples were infected (2 samples from normal species and 2 samples with clinical symptoms). The infected normal samples were Osphronemus goramy and Litopenaeus vannamei. The infected samples with clinical symptoms were Carassius auratus by Aeromonas salmonicida and red zebra cichlid (Metriaclima estherae) by Red Sea Bream Iridoviral Disease (RSBIV). Physical testing supported by molecular detection of aquatic animals can be an effort to manage aquaculture systems in Indonesia. [ABSTRACT FROM AUTHOR]

This study aimed to assess the engagement and interest of rural people in fisheries activities in Argungu Local Government Area of Kebbi State. One hundred and fifty (150) questionnaires were randomly distributed in the three villages. The questionnaires consisted of socioeconomic Characteristics as well as the current engagement of the rural people in fisheries activities and their interest in fish farming. The data obtained from the questionnaires was analyzed using descriptive statistics. Results indicate that the majority (73.3%) of these fish farmers are male, compared to (26.7%) who are female. A large proportion of fish farmers have attained primary education (30.7%). Regarding marital status and income levels, (66%) of the fish farmers are married and (68%) of the fish farmers earn less than 10,000 Naira monthly. The results on engagement and interest of smallholder farmers in fish farming enterprises show that (52.7%) of the fish farmers are actively engaged in fish farming. Fish farming enterprises reveal that smoking is the most commonly used method, with (53.2%) of the respondents favoring it. The most prevalent constraints in fish farming enterprise indicate that (58%), is the poor marketing system and poor storage facilities, which affects (56.7%) of the smallholder fish farmers. Based on this, it is recommended that there is a need to assist in setting up small-scale fish farming projects in rural areas with proper monitoring and supervision and Small-scale fish farming policies and practices to significantly improve food security, rural incomes and sustainable aquaculture development. [ABSTRACT FROM AUTHOR]

Aquaculture production has been growing consistently over the last few decades to meet the increasing animal protein demand of the human population. However, increased production and rearing intensities raise the challenges of guaranteeing fish health and welfare, which is essential to avoid losses and ensure product quality. Biomarkers can provide insights into the fish's nutritional, physiological, and health status, and aid in the evaluation of early nutritional and physiological imbalances, distress conditions, and pathological diagnosis. The discovery and validation of biomarkers rely mostly on the use of information provided by different parameters, including biochemical, metabolic, or immunologic, as well as several omics, from genomics and transcriptomics to proteomics and metabolomics. In this review, a summary of the main biomarkers used in aquaculture is provided along with an overview of the main omics technologies available for further biomarker research. This review also highlights the need to develop non-lethal biomarkers that can easily and quickly be measured to provide a prompt response to producers. [ABSTRACT FROM AUTHOR]