Search Results (1,272)

Underwater optical sensor networks are essential for fish monitoring, yet imagery is often affected by illumination variability, low contrast, and complex backgrounds. Attention mechanisms are vital for feature representation in deep networks, yet existing approaches often struggle with spatial information loss and limited multi-scale interaction under such challenging conditions. This paper introduces Convolution to Interactive Capture and Recalibration Enhancement (C2ICARE), a lightweight attention module designed to overcome these challenges. The principal contribution of C2ICARE is the adaptation of memory interaction principles into an edge-oriented attention framework that enhances feature discrimination while maintaining computational efficiency. The architecture employs three core innovations: a 1:3 memory-feature split to preserve context while reducing cost, parallel multi-scale depthwise convolutions (3 × 3 and 7 × 7) for fine-grained and broad feature extraction, and a cross-branch interaction mechanism coupled with a ConvNeXt-style feed-forward network that avoids dimensionality reduction. Experimental results on an underwater fish dataset demonstrate that YOLO26n with C2ICARE achieves a mean average precision (mAP@0.5:0.95) of 0.7033, outperforming Coordinate Attention (+3.8%), FasterBlock (+1.7%), and CBAM (+0.4%) while adding only 0.05M parameters and 0.16 GFLOPs. Multi-objective Pareto Frontier analysis confirms that C2ICARE provides an effective balance between accuracy, efficiency, and generalization for resource-constrained deployment. EigenCAM visualizations further validate that the model focuses on biological morphology rather than background noise. Its lightweight design enables seamless integration with underwater sensor networks and fog platforms for real-time fish detection in aquaculture, commercial fisheries, and scientific research. Future work will investigate broader marine applications and cross-platform deployment scenarios. The code is available on GitHub. Full article

The sea cucumber Apostichopus japonicus is of great economic value and is mainly cultivated in China. The application of formulated feeds has been widely used in massive sea cucumber aquaculture in recent years. With the attempt to investigate and evaluate the potential of mulberry leaf powder (MLP) as a dietary supplement for sea cucumber aquaculture (especially in winter), a 45-day feeding trail was carried out in winter in this study. Growth performance, digestive and redox-related enzyme activities, and the microbiota of intestinal contents were determined and compared between a basic diet and diets with different MLP-administration levels. The results showed that (1) MLP supplementation has a positive effect on the growth performance of sea cucumber; (2) increased activities of protease and lipase were observed in sea cucumber fed with MLP diets; (3) increased redox-related enzyme activities were observed in sea cucumber fed with 2% MLP diets; and (4) MLP supplementation has a regulatory effect on the diversity and relative abundance of microbiota in the intestinal contents of sea cucumber. The optimal dose of dietary MLP for growing sea cucumbers in winter was 2% dry weight. All data observed in this study will provide new clues for developing formulated feeds for massive sea cucumber aquaculture. Full article

In intensive aquaculture, non-invasive real-time monitoring of morphological traits and body weight of largemouth bass (Micropterus salmoides) is essential for precision feeding and yield estimation. Manual measurement is laborious and stressful, whereas vision-based methods are challenged by insufficient dual-view feature fusion, poor robustness to underwater noise, and over-parameterized models unsuitable for edge deployment. To address these issues, a lightweight framework, MECT-MobileViT, is proposed based on MobileViT-xxs. A Morphometric-Guided Multi-Scale Fusion module is designed to couple physical priors with dual-branch visual features, strengthening shape–weight association. An ECA-NL attention block employing instance normalization, GLU gating, and threshold filtering is embedded to enhance feature robustness against visual disturbances typical in aquaculture and to accentuate critical morphological features. A three-stage synergistic pruning strategy—attention head pruning, structured channel pruning, and depthwise separable attention substitution—is applied to achieve substantial compression while preserving representational capacity. Experiments on a self-built lateral–dorsal dual-view dataset show that the proposed model significantly outperforms mainstream benchmarks. The pruned version attains an R² of 0.8266 and an RMSE of 16.4201, with less than 2% accuracy degradation relative to the best unpruned model, and contains only 7.34 M parameters. This study demonstrates a promising prototype for contactless, stress-free weight estimation in largemouth bass and offers new technical insights into feature fusion, noise suppression, and collaborative model compression for aquaculture visual perception. Full article

The silver pomfret (Pampus argenteus) is a high-value marine food fish, but its aquaculture is limited by juvenile intestinal immaturity, characterized by impaired digestion, barrier dysfunction, and microbial dysbiosis. This study evaluated whether early-life dietary inulin could improve intestinal health and muscle nutritional composition. After an 8-week feeding trial, fish fed a 5 g/kg inulin-supplemented diet showed improved growth performance, as reflected by higher final body weight (+17.2%), WGR (+18.5%), and SGR (+6.4%) than the control group. These benefits were associated with enhanced intestinal morphology, increased α-amylase and lipase activities, upregulated expression of tight junction genes, and a remodeled gut microbiota. These gut-associated changes were accompanied by improved selected muscle compositional traits. Specifically, inulin supplementation enriched essential amino acids, including methionine and threonine, as well as flavor-related amino acids, such as glutamate, glycine, and serine. Meanwhile, the muscle lipid profile was also modified, as reflected by reduced levels of selected saturated fatty acids and increased levels of monounsaturated fatty acids, particularly oleic acid. Collectively, our findings suggest that early-life dietary supplementation with 5 g/kg inulin may support intestinal homeostasis-related indicators and improve selected muscle nutritional traits in farmed silver pomfret. Full article

Saline–alkaline aquaculture is a promising strategy to alleviate freshwater shortages; however, such environments severely impair fish growth and physiological homeostasis. Nutritional regulation has been proposed to improve stress tolerance, yet the benefits of single additives are often limited under the multifactorial challenges imposed by saline–alkaline conditions. Therefore, a compound feed additive (CFA) consisting of glutamate, cholesterol, β-glucan, myo-inositol, zinc methionine, and curcumin was developed and evaluated in Nile tilapia (Oreochromis niloticus). To assess the robustness and practical applicability of this nutritional strategy, three independent feeding trials were conducted using different commercial basal diets as validation systems. Within each dietary system, fish were reared under freshwater (FW), saline–alkaline water (SAW), or saline–alkaline water supplemented with CFA (SAW+CFA). Saline–alkaline stress significantly reduced WG and SR, increased FCR, and elevated VSI and HSI, indicating impaired growth performance and metabolic burden. These changes were accompanied by increased serum glucose and ion concentrations (Na⁺, K⁺, Cl⁻), elevated ammonia levels, and reduced crude protein content. Dietary CFA improved growth and feed utilization under saline–alkaline conditions. It enhanced hepatic glycogen content and reduced serum glucose levels. Meanwhile, it downregulated glycolysis-related genes (hk, pfk1, pk) and upregulated genes involved in gluconeogenesis and the pentose phosphate pathway (g6pase, pc, g6pdh), indicating altered glucose metabolism and improved energy homeostasis. Saline–alkaline stress induced oxidative stress, apoptosis, and histological damage in the liver, whereas CFA alleviated these alterations by reducing MDA levels, enhancing antioxidant enzyme activities (CAT, GSH-Px, T-SOD) and suppressing apoptosis-related genes (caspases, p53, c-myc). In addition, CFA alleviated saline–alkaline stress-induced gill structural damage and reduced serum ion concentrations while modulating ion transport-related gene expression, suggesting improved osmoregulatory capacity. It also enhanced ammonia metabolism and transport, as reflected by reduced serum ammonia levels and altered expression of related genes. Furthermore, Saline–alkaline stress impaired intestinal structure and function, whereas CFA improved intestinal villus structure, increased digestive enzyme activities (amylase, trypsin, lipase), and suppressed pro-inflammatory genes (il-1β, il-8). Importantly, similar beneficial response patterns were observed across the three independently analyzed dietary systems. Overall, CFA improved saline–alkaline adaptability of Nile tilapia and was associated with improvements in energy metabolism, oxidative homeostasis, osmoregulation, ammonia detoxification, and intestinal function, providing a practical nutritional strategy for saline–alkaline aquaculture. Full article

The increasing spread of invasive alien species (IAS) represents one of the major causes of biodiversity loss, making containment practices necessary. In this regard, the circular economy framework proposes to reuse the biomass from IAS in growing sectors such as aquaculture, in which more sustainable practices are required. This study evaluated the possibility of using biomass derived from two widespread freshwater IAS, Procambarus clarkii and Silurus glanis, as dietary ingredients for Oncorhynchus mykiss. Experimental diets were formulated by incorporating 20% of IAS-derived muscle powder into a commercial feed, and their effects were assessed through a 35-day feeding trial. Chemical analyses confirmed the nutritional suitability of the formulated diets and the absence of antibiotic residues. No mortality or significant differences in growth performance were observed among treatments. Blood biochemical parameters showed limited variations, remaining within physiological ranges, while oxidative stress biomarkers indicated only minor, diet-specific responses without evidence of oxidative damage. An increase in Hsp70 expression suggested adaptive physiological responses rather than pathological stress. Histological analyses of liver and gut tissues revealed no structural alterations across experimental groups. Overall, the results demonstrate that the inclusion of IAS-derived biomass at 20% is well tolerated by O. mykiss and does not impair fish health. These findings support the potential of invasive species valorization as a sustainable strategy for aquaculture feed production, contributing to both resource efficiency and ecosystem management. Full article

In cage aquaculture, precise estimation of fish biomass is critically important for determining appropriate feeding strategies and evaluating production capacity. Currently, prevailing fish counting approaches heavily rely on acoustic or optical technologies. However, the accuracy and reliability of the obtained data are largely compromised by factors such as fish occlusion and water turbidity in practical cage farming environments. To address this limitation, this study proposed a novel method for estimating fish population size deduced from dynamic feeding information, based on the model integrated environmental and biological factors, feed intake and biomass. A 10-week feeding experiment was carried out to collect multidimensional data including feed intake, growth parameters, and environmental variables to construct a dataset correlating feeding amount with primary influential factors. Herein a bioenergetics-informed radial basis function neural network, optimized via particle swarm optimization (BE-PSO-RBF), was developed based on those empirical data. Model validation using 47 independent test samples showed that the hybrid model achieved a mean absolute error (MAE) of 26.82, a root mean square error (RMSE) of 35.62, and a mean absolute percentage error (MAPE) of 4.14%, confirming its robust generalization performance. These findings suggest that feed-intake-based population estimation may provide a feasible complementary approach for fish population assessment under cage farming conditions similar to those investigated in this study. Full article

The gut microbiome of rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) is increasingly recognized as a functional interface linking dietary inputs, epithelial barrier integrity, mucosal immunity, environmental stress, disease susceptibility, and antimicrobial-resistance risk in intensive aquaculture. Based on available salmonid studies and relevant evidence from broader fish and aquaculture systems, this review synthesizes current knowledge on salmonid gut microbial composition, nutritional modulation, microbiome–mucosal immune interactions, aquaculture stressors, antibiotic exposure, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), metagenomics, multi-omics, and emerging microbiome-informed decision-support tools. Current evidence does not support a universally stable single-core microbiota in these species. Instead, community structure is shaped by developmental stage, freshwater–seawater transition, intestinal segment, digesta versus mucosa sampling, diet, temperature, stress, health status, and methodological workflow. Feed substitution and functional additives can remodel the gut microbiota, but these shifts should be interpreted alongside histology, barrier function, metabolic profiles, immune indicators, and disease-resistance phenotypes. Antibiotic exposure may reduce acute bacterial disease pressure while disturbing community structure and potentially enriching ARGs or ARG–MGE associations. Risk assessment should therefore move beyond ARG abundance toward host–ARG–MGE linkage using shotgun metagenomics, metagenome-assembled genomes, long-read sequencing, Hi-C, and externally validated multi-omics models. Machine learning and artificial intelligence approaches may support feature screening, risk stratification, and decision support, but their application in salmonid gut-health management remains at an early stage and requires external validation across sites, production stages, diets, and seasons. Full article

Plant-based formulations supplemented with probiotics are a promising strategy to improve nutrient bioavailability in aquaculture, yet mechanistic understanding of microbial modulation of host metabolism remains limited. We evaluated whether supplementation with Bacillus velezensis (Sp1) and B. amyloliquefaciens (Sp3) influences metabolic efficiency and energy allocation in sub-adult red abalone (Haliotis rufescens). Over 180 days, animals were fed a plant-based or a fishmeal-based diet—both probiotic-supplemented and matched in protein and energy—and compared with fresh kelp (Macrocystis pyrifera) as a control. Metabolic performance was assessed from oxygen consumption, relative specific dynamic action (SDA) index, ammonia excretion and Oxygen-to-nitrogen ratio (O:N) ratio. The Bacillus-supplemented plant-based diet achieved metabolic efficiency comparable to M. pyrifera, with minimal SDA (4.7% vs. 4.3%) and commercially viable growth (2.07 mm/month). The O:N ratio indicated diet-specific, time-dependent shifts in substrate use. The fishmeal-based diet—despite identical macronutrient and probiotic composition—produced a markedly higher postprandial metabolic cost (SDA = 21.0%), consistent with reduced compatibility between high animal protein and herbivorous digestive physiology. Overall, probiotic supplementation may help convert plant-based ingredients into metabolically efficient functional feeds, offering a more sustainable approach that reduces dependence on marine-derived ingredients. Full article

Reducing reliance on supplemental fish oil is central to sustainable aquaculture, but the molecular consequences of replacing it with vegetable oils remain poorly characterized in the juvenile Chinese soft-shelled turtle (Pelodiscus sinensis). We evaluated whether full substitution of the supplemental dietary fish oil (FO) with linseed oil (LO) or soybean oil (SO) compromises hepatic lipid metabolism in Pelodiscus sinensis. Three isonitrogenous and isolipidic diets, sharing identical fish meal and other ingredient bases and differing only in the supplemental lipid (4% FO, LO or SO), were fed to triplicate groups of juvenile turtles (initial body weight 55.0 ± 0.05 g) for 8 weeks. Growth performance, survival, feed conversion ratio, and serum biochemistry were unaffected. However, both vegetable oil diets altered tissue fatty acid composition, raising n-6 PUFA and lowering n-3 LC-PUFA and the n-3/n-6 ratio in liver and muscle (muscle EPA and DHA each decreased by approximately 40%); the SO group additionally exhibited elevated hepatic malondialdehyde, whereas hepatic lipid droplet area and lipid content did not differ significantly among groups. Liver transcriptomic profiling identified 262 (LO vs. FO) and 214 (SO vs. FO) differentially expressed genes, converging on lipid storage and bile acid metabolism. RT-qPCR confirmed the up-regulation of PLIN3, G0S2 and APOF and the down-regulation of CYP7A1. Over 8 weeks, replacement of supplemental FO maintained growth without overt impairment while altering tissue fatty acid profiles and the hepatic expression of key lipid metabolism genes. Full article

Curcumin (Cur), a polyphenol with excellent antioxidant and anti-inflammatory properties, is widely used in aquaculture. However, its low water solubility limits bioavailability. This study first investigated the effects of a highly water-soluble and bioavailable valine-curcumin (Val-Cur) on growth performance, antioxidant capacity, inflammatory factor expression and gut microbiota in juvenile largemouth bass. A total of 450 healthy largemouth bass (initial weight 12.00 ± 0.45 g per fish) were randomly divided into six groups: the basal diet group (CK), the group supplemented with 60 mg/kg of curcumin (Cur), and groups that were fed with 15, 30, 60, and 120 mg/kg of Val-Cur. Each group had three replicates (25 fish per replicate). After 8 weeks, compared with both the CK and Cur groups, 30–60 mg/kg Val-Cur displayed significantly increased growth rates, specific growth rates, and protein conversion efficiency, and significantly decreased the feed conversion ratio. Quadratic regression analysis indicated that the optimal supplementation level was approximately 51.62 mg/kg Val-Cur. The Cur and Val-Cur between 30 and 60 mg/kg groups also displayed significantly improved serum biochemical indicators (↑HDL-C, ALB, LZM, CAT and SOD, and ↓MDA). These groups also promoted the expression of intestinal anti-inflammatory factors (TGF-β1 and IL-10) and physical barrier genes (Claudin1, Occludin and Claudin4). In terms of regulating the intestinal microbiota, both Cur and Val-Cur significantly reduced the bacterial diversity (↓Sobs, Chao1 and PD indices) and increased the evenness of bacterial distribution (↑Simpson, Shannon and Pielou indices). In addition, the abundance of some potential pathogens (e.g., Plesiomonas, Plesiomonas shigelloides, and Pseudomonas fluorescens) significantly decreased, while the abundance of beneficial bacteria (e.g., Faecalibaculum, Faecalibaculum rodentium and Lactobacillus murinus) significantly increased. Pearson’s correlation analysis showed that the increase in the abundance of beneficial bacteria was positively correlated with improvement in growth performance, serum biochemical and antioxidant capacity indicators. In summary, Val-Cur exerted superior biological effects at lower dietary inclusion levels than Cur. This study laid a theoretical foundation for elucidating the mechanism of Val-Cur in improving fish immunity and promoting the application of water-soluble curcumin in aquaculture. Full article

Advanced methodologies for Botryllus schlosseri artificial seawater systems are needed to decrease dependency of large-scale culture on natural seawater and expand this important new model organism to more inland laboratories. We constructed two botryllid tunicate customized closed aquaculture systems, a static system consisting of aerated jars fed commercial filter feeder diet, and a recirculating aquaculture system (RAS) consisting of pertinent marine RAS components fed live microalgae and zooplankton diets. Initially, static tunicate culture yielded exponential growth in contrast to poor survival and negligible growth observed in RAS tunicates. RAS modifications were made to increase water treatment proficiency, which improved tunicate survival and growth. Experiments were performed isolating feed and water type as variables differentiating static and RAS and evaluating their specific effects. Live feed promoted five-fold greater growth relative to a commercial concentrate diet. Tunicates maintained in optimized RAS water achieved two-fold faster growth relative to animals in freshly prepared artificial seawater. Subsequent procedural modifications combined with the RAS revisions resulted in growth rates comparable to the static system. Both optimized systems are suitable for long-term husbandry of botryllid tunicate populations supporting both sexual and asexual modes of reproduction, with a current RAS residence time of over 24 months. Full article

Sustainable management of intensive aquaculture areas requires a profound understanding of the feeding interactions between cultured species and their environment. This study compared the seasonal feeding performance of the Pacific oyster Magallana gigas and the bay scallop Argopecten irradians on the southern coast of Korea using the biodeposition method. Our results demonstrated significant interspecific differences: M. gigas adopted a ‘high-throughput’ strategy with superior filtration rates, whereas A. irradians exhibited a ‘pre-ingestive selective’ strategy characterized by higher pseudofeces production and particle rejection. Based on these findings, we propose three core spatial management strategies: (1) horizontal re-arrangement to optimize food utilization by positioning high-efficiency filter feeders upstream; (2) a dynamic vertical positioning strategy to mitigate metabolic stress during environmental shifts; and (3) an environmental management model incorporating species-specific biodeposition loads. These strategies provide a scientific foundation for maximizing growth efficiency while ensuring the ecological sustainability of intensive aquaculture systems. Full article

The black sea cucumber, Holothuria forskali, is an emerging target species for aquaculture; however, knowledge of its biology remains limited. Investigating its associated microbiota is a crucial step toward developing a controlled and sustainable aquaculture. In this study, the microbiota of three different body compartments of the host H. forskali—namely, the dorsal epidermis, the posterior intestinal content, and the coelomic fluid—were analysed using targeted metagenomics (V3-V4 rRNA 16S Metabarcoding). We compared host-associated communities with bacterial environmental communities across three periods in 2020 at two sites in south Brittany, totalling 309 analyses (36 environmental samples and 273 sea cucumber samples). The objective was to explore the diversity of the sea cucumber microbiota from the external to the internal regions of the animal. Thus, a total of 8695 OTUs were identified and classified into 52 bacterial phyla, 119 classes, and 45,596 orders. The results highlighted (1) anatomical compartmentalisation—with significantly different bacterial assemblages in terms of diversity, composition, and abundance across the three body regions—(2) host versus environment differences, and (3) temporal variations, as microbial community structures shifted significantly in winter compared to summer and autumn. This analysis identified specific taxa and families associated with each compartment with a potential role in host health. Results also showed relationships between the sea cucumber microbiota and their ambient environment. In fact, the presence of common bacterial taxa observed in the sediment and in the gastrointestinal microbiota supported the feeding behaviour of H. forskali. The sea cucumber microbiome thus appears to be compartmentalised “anatomically”, exhibiting a relatively low abundance of bacteria in the coelomic cavity, distinct from that of the microbial communities of seawater and sediments. This study highlighted the importance of the microbiota for the host and confirmed the existence of a core microbiota within H. forskali. Full article

Beyond their role as fishmeal replacements in aquafeeds, insects may enhance fish resistance to microbial diseases and improve feed shelf life through the presence of antibacterial compounds. This study evaluated the antibacterial activity of extracts from silkworm pupae (Bombyx mori, BM), larval meals of black soldier fly (Hermetia illucens, HI), mealworm (Tenebrio molitor, TM), and superworm (Zophobas morio, ZM), and adults of house cricket (Acheta domesticus, AD), two-spotted cricket (Gryllus bimaculatus, GB) and weaver ant (Oecophylla smaragdina, OS). The extracts were tested against ten Gram-negative marine bacterial pathogens associated with aquaculture disease outbreaks, as well as the Gram-positive bacterium, Bacillus thuringiensis. The antibacterial activity of aqueous and solvent-soluble extracts was assessed using agar diffusion assays, turbidimetric growth kinetics, and MTT metabolic assays. Several insect extracts exhibited moderate to strong antibacterial activity. In particular, the aqueous extracts of BM and GB, the methanolic extract of HI, and the isopropanolic extracts of HI and OS were effective against multiple bacterial strains, including strains with reduced susceptibility to the reference antibiotics bacitracin, oxolinic acid, and streptomycin. These findings highlight the potential of HI, GB and especially OS as functional ingredients or feed additives for aquaculture. Full article