Search Results (588)

Saline and alkali aquaculture offers a sustainable strategy to alleviate pressure on freshwater resources and ecologically ameliorate saline and alkali environments; however, information regarding the quality of aquatic products from such conditions remains scarce. This study evaluated the nutritional components, color, texture, and flavor profiles of grass carp cultured under three representative saline and alkali conditions in China: carbonate (CB), chloride (CR), and sulfate (SF), with a freshwater-cultured grass carp (Ctenopharyngodon idellus) serving as a control (CK). The results obtained in our study showed that the CB group exhibited the lowest muscle water content (68.96 ± 0.04%). Crude fat and sodium levels were significantly elevated in all treatment groups compared to the CK group (p < 0.05). Conversely, the CK group displayed superior springiness and higher concentrations of geosmin, adenine, and uracil. Notably, the CR group exhibited the highest L* and whiteness values, whereas the CB and SF groups possessed significantly higher collagen content and enriched EPA and DHA levels. These findings demonstrate that saline and alkali conditions distinctly modulate the nutritional and flavor profiles of grass carp, highlighting their potential for producing value-added aquatic products under saline and alkali conditions. Full article

The phenomenon of climate change has exerted an escalating degree of pressure on coastal livelihoods in Bangladesh. In this region, communities find themselves confronted with a dual challenge, being exposed to both rapid-onset hazards, including cyclones, storm surges, and floods, and slow-onset stresses, such as salinity intrusion and sea-level rise. These hazards have ramifications for agriculture, aquaculture, food security, and livelihood sustainability. However, extant studies frequently examine individual risks, livelihood sectors, or disaster responses in isolation. Consequently, there is a paucity of research that comprehensively examines the influence of multiple climate-related hazards on coastal livelihoods and the adaptation options that are locally feasible in overcoming institutional, community, and financial constraints. This study synthesizes evidence from the published literature and is complemented by qualitative evidence from 30 open-ended questionnaires with farmers in selected coastal areas of Bangladesh. The objective of this synthesis is to validate and contextualize the current livelihood conditions, climate-related challenges, and locally adopted adaptation practices. The analysis examines four interconnected dimensions. The following elements are to be considered: (i) climate-related hazards and their sectoral impacts, (ii) livelihood opportunities and vulnerabilities, (iii) adaptation practices, and (iv) institutional, community, and financial constraints. These elements are to be complemented by a SWOT assessment of livelihood adaptation options. The findings indicate that a combination of factors, including salinity intrusion, cyclones, storm surges, flooding, sea-level rise, drought, and changing temperature and rainfall patterns, collectively impose constraints on agricultural and aquaculture productivity, thereby exacerbating livelihood insecurity. Concurrently, practices such as salt-tolerant crop cultivation, sorjan farming, freshwater conservation, pond-dyke vegetable cultivation, tower cultivation, composite agriculture, and environmentally responsible aquaculture offer promising pathways for livelihood adaptation. However, the limited availability of infrastructure, inadequate institutional coordination and stakeholder participation, and insufficient financial resources act as constraints on their broader adoption. The manuscript makes a similar observation regarding infrastructure, institutional support, and funding, which are identified as significant constraints. Concurrently, it acknowledges technological development, stakeholder participation, and climate-resilient livelihood opportunities as crucial avenues for enhancement. This study thus posits a series of recommendations for enhancing the resilience and sustainability of coastal livelihoods in Bangladesh. These recommendations encompass the implementation of hazard-specific and livelihood-oriented adaptation measures, the facilitation of access to climate-resilient technologies and financial resources, and the establishment of a more robust coordination framework among diverse stakeholders. The proposed framework involves collaboration between agriculture, fisheries, water management, disaster management, local government, non-governmental organizations (NGOs), academic institutions, and community organizations. These recommendations align with the manuscript’s proposed measures for communities dependent on salinity, cyclones, storm surges, floods, agriculture, and aquaculture. Additionally, the manuscript places emphasis on cross-sectoral governance. Full article

Procambarus clarkii and Macrobrachium nipponense are two freshwater shrimp species used in rice-farming systems. To guide their cultivation in saline–alkaline waters, two 96 h experiments were conducted on juvenilels of each species using 540 juveniles per species (initial body length: 1.51 ± 0.16 cm for P. clarkii and 0.88 ± 0.03 cm for M. nipponense): combined salinity–pH stress (0/15.0/25.0‰ at pH 7.4/9.0/10.0) and NaHCO₃ alkalinity stress (0/10/20 mmol/L). Under salinity–pH stress, survival of P. clarkii was 100%, 72.23%, and 53.33%, respectively; for M. nipponense, it was 93.33%, 61.13%, and 23.33%. Under alkalinity stress, survival of P. clarkii was 92.22%, 82.22%, and 61.11%; for M. nipponense, it was 91.11%, 65.55%, and 46.67%. In both species, superoxide dismutase, acid phosphatase, and alkaline phosphatase decreased while malondialdehyde increased with stress intensity. Metabolomics revealed species-specific reprogramming: P. clarkii upregulated protective lipids (e.g., glycerophosphoethanolamines, fatty acid esters), whereas M. nipponense showed depletion of critical osmolytes (glycerophosphocholines) and accumulation of apoptosis-related ceramides. KEGG analysis confirmed that energy metabolism, amino acid homeostasis, and ABC transporters were primary pathways affected. In conclusion, extreme stress significantly reduced survival, suppressed immunity, and triggered metabolic reprogramming in both species, with P. clarkii showing substantially higher tolerance. For cultivation, P. clarkii is preferred in moderately high saline–alkaline waters, while M. nipponense requires low-alkalinity freshwater with strict monitoring. These findings support species-specific management of saline–alkaline rice–shrimp systems. Full article

Sperm activation and movement are essential in freshwater fishes, where limited energy reserves and a short motility duration require rapid ATP-driven motility regulated by osmolality and ions. However, the physiological and molecular mechanisms underlying osmolality and ion regulation in mandarin fish (Siniperca chuatsi) remain unclear, and ions in aquaculture systems may exert additional effects. Here, we integrated physiology with transcriptomic and proteomic analyses to characterize the effects of osmolality and ions on sperm motility and identify key genes, proteins, and regulatory networks involved in sperm activation and movement. Low osmolality (<50 mOsm/kg) promoted sperm activation, with sperm motility progressively decreasing as osmolality increased. Although relatively high osmolality supported motility maintenance, the initial motility was comparatively low, indicating the limited energy reserves of freshwater fish spermatozoa. Na⁺ and K⁺ activation media enhanced motility, whereas Ca²⁺ supplementation suppressed activation. Ca²⁺ levels below a 1:500 molar ratio (<0.06 mM) did not significantly affect sperm motility, indicating the importance of limiting Ca²⁺ exposure during fertilization. Multi-omics analyses identified six differentially expressed genes, including grin3bb, cacna1c, and chrna7, and 35 differentially expressed proteins, including ATP1B, PRKCB, and CPT1A, as key molecules associated with Na⁺, K⁺, and Ca²⁺ signaling and energy metabolism. The calcium signaling pathway, cAMP signaling pathway, and oxidative phosphorylation were significantly enriched in KEGG enrichment analysis, while Gene Ontology (GO) enrichment analysis identified ion signaling and energy metabolism, including ion transport, the ATP metabolic process, and the glycolytic process. Our findings provide a putative regulatory network for sperm activation and movement in mandarin fish and a basis for optimizing artificial fertilization. Full article

Large-water fisheries are central to China’s freshwater aquaculture, but their sustainability is threatened by eutrophication from traditional high-density stocking. Polyculture of grass carp and crucian carp offers an ecologically sound alternative; nevertheless, its direct effects on plankton communities require further study. We conducted monthly sampling from July to December 2023 (over two seasons within a single aquaculture cycle) in polyculture ponds and used eDNA metabarcoding (18S V9) with high-throughput sequencing. We detected 288 planktonic taxa across 28 phyla and 290 genera based on eDNA sequence assignment. Alpha diversity (Chao1, Shannon, Simpson) peaked in autumn and was lowest in winter, with Chao1 showing greater seasonal variation. Beta diversity revealed season as the dominant factor (R² = 0.287, p = 0.012), with significant summer–winter divergence. Null-model analysis indicated stochastic processes (56.3%) slightly exceeded deterministic filtering (43.7%), and stochasticity was higher in summer (67.2%), suggesting fish bioturbation and grazing create heterogeneous microhabitats. Co-occurrence networks were dominated by positive links (87.3%), with Cryptomonas as a central hub, implying mutualism and niche complementarity. This study is the first to integrate eDNA metabarcoding with community assembly theory to elucidate seasonal succession and interactions in this polyculture. Our findings confirm that polyculture sustains diversity and stability via top-down (grazing) and bottom-up (nutrient release) effects, providing eDNA-based taxonomic evidence for management of large-water aquaculture. Full article

The Siberian sturgeon (Acipenser baerii, Brandt, 1869) is a potamodromous freshwater species with major ecological and commercial importance. Natural populations across the main Siberian River basins have declined so severely that the species is now classified as Critically Endangered on the IUCN Red List. This narrative analysis synthesizes current scientific knowledge regarding the ecology, reproductive biology, conservation status, and nutritional value of products derived from A. baerii, with the aim of providing an integrated perspective on this species, which has recently been introduced into Romanian aquaculture and occupies the interface between biodiversity and human consumption needs. The species’ remarkable ecological and morphological plasticity, which underlies its wide natural distribution in the Ob, Irtysh, Yenisei, and Lena River basins, has also made it the dominant species in global sturgeon aquaculture, commercially farmed in Europe, Asia, and South America. Reproductive management in farming systems relies on hormonal induction, non-invasive maturity assessment, and controlled hatchery practices, while emerging no-kill technologies enable repeated caviar harvesting without sacrificing the female, improving both ethical standards and economic efficiency. From a nutritional standpoint, A. baerii yields two high-value products: caviar, a rich source of the long-chain polyunsaturated fatty acids EPA and DHA, whose dietary intake has been associated with cardiovascular and neurodevelopmental benefits in the broader nutrition literature, and meat, characterized by high-biological-value protein, a favorable amino acid profile, and significant omega-3 content. By-products such as skin, swim bladders, glands, and cartilage contribute to the higher-value utilization of the species within the circular bioeconomy. Still, notable gaps remain in genetics and sex determination methods, in early life behavioral ecology, and in cryopreservation protocols. Future work should also look at more sustainable feed formulations and new value-added products. Full article

Bacterial diseases caused by Flavobacterium covae (Fc), Vibrio harveyi (Vh), Vibrio vulnificus (Vv) and Photobacterium damselae (Pd) seriously constrain Asian seabass aquaculture. Here we dissect the mucosal immune mechanisms engaged by a five-month sequential vaccination strategy that combines nanoemulsion immersion priming with multivalent oral hydrogel boosting. Juvenile seabass were vaccinated, then challenged with F. covae by freshwater immersion and with a Vibrio–Photobacterium (Vh/Vv/Pd) mix by immersion or intraperitoneal injection. Gills were sampled after immersion challenges and intestine after injection, and profiled by RNA sequencing and label-free quantitative proteomics, with selected genes validated by RT-qPCR. Principal component analysis showed clear separation of vaccinated and control fish in all tissues and challenges, indicating a strong and coherent transcriptional reprogramming. Vaccination markedly increased the number of upregulated genes, with Gene Ontology enrichment revealing dominant signatures of ribosome biogenesis, RNA processing, lysosomal organization and immune response. KEGG analysis highlighted cytokine receptor interaction; NOD and Toll-like receptor signaling; oxidative phosphorylation; and phagosome, lysosome and cell adhesion molecule pathways, consistent with heightened antimicrobial readiness. Volcano plots and focused heatmaps showed strong induction of interferon-stimulated genes, cytokines and chemokine receptors, complement components, macrophage mannose receptor, epithelial barrier mediators and numerous immunoglobulin transcripts, with tissue- and challenge-specific patterns. Proteomics corroborated these trends, demonstrating a higher abundance of immunoglobulin heavy chains, complement proteins, cathepsins, heat shock and redox chaperones, ribosomal proteins and cytoskeletal and adhesion regulators in vaccinated mucosae. Integrated pathway mapping linked endothelial adhesion molecules and leukocyte integrins with T cell costimulation networks and an intestinal immune network for immunoglobulin production, including enhanced pIgR-mediated transcytosis. Overall, the sequential vaccination regimen was associated with coordinated transcriptomic and proteomic signatures related to epithelial responses, innate immunity, and humoral immune functions across gill and intestinal tissues. These molecular patterns were accompanied by improved survival following bacterial challenge; however, the present data do not directly demonstrate the functional activity of the inferred immune mechanisms in Asian seabass. Full article

The Chinese lizard gudgeon (Saurogobio dabryi) is an economically important freshwater species within the Cyprinidae family, abundant in the middle and lower reaches of the Yangtze River and its adjacent basins. As a promising species suitable for aquaculture in China, the lack of genomic resources has rendered the genetic breeding and conservation research. Here, we present the first chromosome-level genome assembly of S. dabryi using PacBio HiFi long reads, short reads, and Hi-C sequencing data. The final assembly reaches a total size of 1.09 Gb and Hi-C scaffolding anchors 99.55% of the assembled contigs onto 25 chromosomes, with a scaffold N50 reaching 43.15 Mb. The final genome assembly shows a BUSCO completeness of 98.39%. We annotated 659.55 Mb repetitive sequences and 26,036 protein-coding genes, 99.47% of which are functionally annotated. Comparative phylogenomic analysis clarifies the phylogenetic position of Saurogobio within Gobioninae. This high-quality genome provides a critical genetic basis for exploring cyprinid phylogeny, benthic adaptive evolution, genetic improvement, and conservation efforts of S. dabryi. Full article

Ecuadorian aquaculture plays an increasingly important role in food security, providing a sustainable complement to capture fisheries. Manabí constitutes a key economic sector that contributes to employment generation, income diversification, and supply of high-quality protein. However, the sector’s heterogeneity and limited legal registration of enterprises hinder the development of policies and targeted interventions. This study characterizes aquaculture enterprises in Manabí, integrating productive, technological, and socio-economic variables obtained from field surveys. Three distinct entrepreneurship patterns were identified: small-scale, informal farms cultivating native species with low technology but characteristics that may contribute to socio-ecological resilience; semi-formal producers operating with intermediate technology and mixed species; and freshwater shrimp farms operating at the largest relative scale within the sample, though still small-scale and family-based, with moderate technological development and market integration limited mainly to local and regional markets. The typology focused on a gradient in formalization, technological sophistication, and market orientation among enterprises. These findings provide a comprehensive understanding of aquaculture diversity in Manabí and offer a practical framework for differentiated policy design using a Strategic Producer Positioning Map. Strengthening formalization, technological innovation, environmental management, and social inclusion is essential to enhance the sector’s sustainability and competitiveness, contributing to sustainable blue economy development in coastal Ecuador. Full article

The Jianghan Plain is one of the important freshwater aquaculture regions in China. Accurate information on the spatial distribution and spatiotemporal dynamics of aquaculture ponds is essential for regional ecological management. However, large-scale and accurate identification remains challenging for aquaculture ponds because they have spectral and seasonal hydrological characteristics similar to those of rice fields, rivers, canals, and lakes. In this study, we developed a framework for mapping inland aquaculture ponds using multi-source remote sensing data from Sentinel-2, Sentinel-1, and PlanetScope. The framework integrated elevation-zoned Otsu thresholding for candidate water extraction, phenological features for rice field removal, and object classification based on a Gradient Boosting Decision Tree (GBDT) model using 12 shape and spatial-context features. It was applied to identify aquaculture ponds in the Jianghan Plain from 2016 to 2025. Overall accuracy exceeded 93%, and the F1-score exceeded 0.93 in all validations. Results from different sensors also showed high spatial consistency. In 2025, aquaculture ponds covered 2365.17 km² in the Jianghan Plain and were mainly concentrated in the central and eastern parts of the plain, especially near Honghu Lake and along the Yangtze and Hanjiang river meanders. Over the ten-year period, the aquaculture pond area fluctuated between 2033.58 and 2383.52 km², showing an initial decline followed by recovery. Lost aquaculture ponds were mainly located around lakes, while newly added ponds were mostly distributed along the margins of existing clusters. The decade dataset generated in this study can support freshwater aquaculture management and wetland conservation. Full article

The giant freshwater prawn (Macrobrachium rosenbergii) is a commercially pivotal crustacean species in global freshwater aquaculture, while vibriosis caused by non-O1 Vibrio cholerae has become the primary bottleneck restricting its sustainable intensive farming. Vitamin D₃ (VD₃) is a biologically active fat-soluble nutrient involved in mineral metabolism and immune regulation in animals, yet its effects on the physiological responses of M. rosenbergii under a pathogenic bacterial challenge remain largely unelucidated. In this study, six experimental diets were formulated with graded dietary VD₃ concentrations (0.10, 0.18, 0.28, 0.48, 0.68, and 0.88 mg/kg) to feed juvenile M. rosenbergii (initial body weight: 2.06 ± 0.07 g) for 70 d, followed by a 72 h non-O1 Vibrio cholerae challenge test. The results showed that dietary VD₃ supplementation alleviated the non-O1 Vibrio cholerae-induced histopathological damage in the intestine and hepatopancreas of prawns. VD₃ supplementation significantly modulated antioxidant enzyme activities in a tissue-specific manner: SOD activity increased in the intestine, while CAT and GSH-PX activities increased in the hepatopancreas. However, the MDA, T-AOC, and GSH-PX (intestine) or SOD (hepatopancreas) showed no significant responses, indicating that VD₃’s antioxidant effects were selective rather than comprehensive. Meanwhile, an appropriate amount of VD₃ markedly upregulated the mRNA expression of multiple immune-related genes (pattern recognition receptors, antimicrobial peptides and immune effectors) in a tissue-specific pattern. However, some antioxidant indices and immune-related genes showed no significant responses. Furthermore, VD₃ supplementation significantly modulated certain muscle physicochemical parameters of prawns, including altered redness, cooking loss, and textural characteristics. Based on the evaluated physiological indicators, 0.48–0.68 mg/kg VD₃ appeared to produce the most favorable overall response. These findings suggest that dietary VD₃ may modulate the physiological responses associated with host defense during a bacterial challenge in M. rosenbergii, potentially through modulation of antioxidant capacity and immune-related gene expression, while benefiting the flesh quality. VD₃ is thus a potential nutritional approach for improving health status during a bacterial challenge in freshwater crustacean farming. Full article

The largemouth bass (Micropterus salmoides) is an important freshwater aquaculture species in China, but the increasing incidence of disease under intensive production conditions has become a major constraint on its sustainable development. This study evaluated the effects of dietary Eucommia ulmoides extract (ELE) supplementation on growth performance, immune and antioxidant responses, intestinal health, gut microbiota, and resistance to largemouth bass virus (LMBV) in juvenile largemouth bass. During a 56-day feeding trial, fish with an initial body weight of 13.14 ± 0.11 g were fed diets containing 0, 30, 60, 90, 120, or 150 mg ELE/kg, with three replicate nets per treatment. Dietary supplementation with 60–90 mg/kg ELE significantly increased weight gain rate (p < 0.05). ELE also improved selected serum antioxidant and immune indices, with the most pronounced responses generally observed at intermediate supplementation levels. In the intestine, the increased Nrf2 and decreased Keap1 mRNA expression were consistent with the potential involvement of Keap1/Nrf2-related redox regulation. ELE also modulated the expression of inflammation- and apoptosis-related genes and increased the expression of selected tight-junction-related genes, suggesting a potential contribution to intestinal inflammatory regulation and barrier maintenance. In addition, ELE supplementation was associated with shifts in bacterial diversity and community composition, although the responses varied among supplementation levels. Following LMBV challenge, the 90 mg/kg group showed the highest observed protection, accompanied by lower splenic expression of the largemouth bass virus major capsid protein (LMBV-MCP) and proinflammatory gene expression, suggesting reduced viral activity and host inflammatory responses. Overall, dietary supplementation with 60–90 mg/kg ELE elicited the most favorable combined responses and may contribute to the regulation of growth, antioxidant and immune status, and intestinal homeostasis in largemouth bass. Full article

Shansha Bay, southeastern China, is a typical semi-enclosed bay facing intense anthropogenic pressure, with mariculture production reaching approximately 660,000 tons annually, predominantly driven by the large yellow croaker (Larimichthys crocea) industry. To assess how these pressures influence biodiversity detection, we employed eDNA metabarcoding targeting the 12S rRNA gene to survey fish diversity across 10 sites, integrating both surface water and sediment matrices. A total of 40 species belonging to 16 orders, 27 families and 32 genera, were identified. Among them, L. crocea, Bostrychus sinensis, Clupanodon thrissa and Siganus fuscescens are the dominate species, which comprised over half of all OTUs. Comparison with historical trawl surveys revealed 30 newly recorded species, including the Japanese eel (Anguilla japonica) and oarfish (Regalecus glesne). Alpha diversity was low (Shannon: 0.69–1.93), with significant spatial disparities driven by freshwater runoff and hydrodynamics. While eDNA effectively captured the dominance of cultured species like L. crocea, the extreme biomass signal poses challenges for detecting wild populations. Our findings underscore that a multi-matrix eDNA approach is crucial for accurate biodiversity assessments in aquaculture-dominated coastal ecosystems, although distinguishing wild stocks from aquaculture-derived DNA remains a critical methodological hurdle. Full article

Aquaculture is central to global food security, but intensification of production has increased disease risk and environmental pressure. The gut microbiome of aquatic organisms is now recognized as a key mediator of host physiology, nutrition, immunity, and pathogen resistance, making it a promising alternative to antimicrobial-based disease control. This review summarizes current knowledge on the composition, assembly, and functional roles of the gut microbiome in fish and crustaceans of aquacultural importance. Major bacterial phyla include Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria, Actinobacteria, and Verrucomicrobia. Community structure is shaped by environment, diet, host age, genetics, stress, and stochastic processes, with differences between marine and freshwater systems. The microbiome contributes to immune defense through short-chain fatty acid production, Toll-like receptor signaling, cytokine regulation, mucosal immunoglobulin responses, antimicrobial peptide and bacteriocin production, and competitive exclusion of pathogens. It also supports productivity by improving nutrient assimilation, vitamin and enzyme synthesis, and feed conversion. Probiotics, prebiotics, and synbiotics are discussed as strategies for targeted microbiome modulation, although unstable colonization and the lack of standardized protocols remain major challenges. Overall, targeted microbiome manipulation offers a promising route toward sustainable, antimicrobial-reduced aquaculture. Full article

Background: Soft-shelled turtle (Pelodiscus sinensis), traditionally used for both medicinal and culinary purposes, is rich in high-quality protein and amino acids, making it an excellent raw material for the preparation of bioactive peptides. In recent years, soft-shelled turtle peptides have gradually become a research focus due to their significant physiological functions, including antioxidant, immunomodulatory, and anti-fatigue activities. Methods: This review systematically sorts out and analyzes 76 relevant research papers published from 2002 to 2026 and comprehensively elaborates on the current state of soft-shelled turtle peptide research, encompassing sources, preparation, and purification strategies, while placing special emphasis on the diverse functional activities and the molecular mechanisms underlying the observed bioactivities. Results: For preparation, enzymatic hydrolysis has become the mainstream method due to its high efficiency and mild conditions; fermentation offers the advantages of low cost and the ability to simultaneously remove odours and enhance flavour, demonstrating good application potential. This review summarizes five key bioactivities, including antioxidant, anti-fatigue, antihypertensive, antitumor, and immunomodulatory effects, and specifically focusing on the current evidence from in vitro and animal studies. Antioxidant and antihypertensive activities have been validated in vivo, whereas the rest remain only tested in vitro, highlighting the need for deeper mechanistic investigation. Conclusions: The review provides an in-depth analysis of the molecular mechanisms through which soft-shelled turtle peptides exert their physiological activities, including free radical scavenging and the regulation of signaling pathways. This review highlights the potential of soft-shelled turtles as a sustainable source of bioactive peptides and offers strategic recommendations for future research. Full article