Aquaculture, Fish and Fisheries最新文献

The status of most fish stocks in Madagascar remains poorly documented. Given their importance for food security and livelihoods, it is necessary to define management measures with reliable data. This study applied a length-based Bayesian biomass (LBB) estimation method for analysing the fisheries' representative length-frequency data of seven most commonly caught coral reef fish species in the southwest of Madagascar. Using Froese's indicators, the use of $��\frac{B}{B_0}��$ as a stock status indicator, allows a consistent comparison among species in multi-gear, multi-species fisheries and provides a practical basis for management advice in data-limited contexts. The stock status was determined based on median estimates for the period 2018–2023, which provide an assessment of the overall status. Estimates for 2023 were used to describe the most recent status of the stocks. The outputs of this study provide a guide for fisheries managers, coastal communities and authorities to formulate effective management strategies for the sustainability of the marine fisheries in Madagascar. A key recommendation from the study is the need for fisheries managers to improve fisheries data and to periodically monitor biological indicators to assess the status of small-scale fisheries stocks.

Genetic variation is indispensable for both natural and artificial selection, as well as evolution, adaptation, and the long-term success of selective breeding programs. This study attempted to scrutinise genetic variations and responses within the breeding population of red tilapia across eight generations of selection (2016–2023). A comprehensive dataset comprising 75,950 individual fish, progeny of 1203 dams and 600 sires, with recorded body weights, was analysed. Employing a restricted maximum likelihood approach within a mixed model framework, we estimated variance components and genetic responses for this trait. Our analyses revealed the sustained presence of the additive genetic component throughout the breeding program, with the heritability estimates ranging from 0.17 to 0.27 (± 0.03–0.07) for body weight. Provided with the sustained genetic variance, the selection program significantly enhanced the body weight trait, achieving an average genetic gain of 13.5% per generation (or per year). Regression analysis of estimated breeding values against the year of birth demonstrated a consistent linear genetic trend for body weight across generations, with a regression coefficient denoted as 59.9 g or 1.21 genetic standard deviation unit. In conclusion, our selective breeding program has effectively maintained both genetic variance and genetic response in the selection criterion, specifically body weight, within this closed nucleus population of red tilapia. The abundant presence of heritable genetic components for body weight suggests a continuing response of this population to future selection pressures. Genetic selection emerges as an effective and powerful mean to augment the productivity of animal populations, thereby fostering sustainable aquaculture production.

The scarcity of affordable and high-quality fish feeds limits aquaculture development in many developing countries. The present study assessed the use of linear programming (LP) techniques for formulating Nile tilapia (Oreochromis niloticus) diets and solid-state fermentation (SSF) technology to improve their nutritional value. The formulated diets produced using LP and improved through SSF technology were analyzed for their chemical composition. The combined techniques enable the production of high-quality fish feeds at low cost of 0.4 USD per kilogram. The resulting diets contained 36.2% of crude protein and 5.6% of crude lipid, and adequate minerals and essential amino acids and minerals align with Nile tilapia requirements. The fermented feeds provided optimum levels of lysine (15 g/kg), tryptophan (3.59 g/kg), and methionine-cysteine (11.25 g/kg), supporting healthy growth in juvenile tilapia. Overall, the model provides practical guidance for small-scale fish farmers and local feed producers in Tanzania to develop cost-effective, nutritionally balanced feeds.

Transcriptome differences between wild and hatchery-reared Gibelion catla collected from Halda (HL) and Padma River (PD) as wild and a hatchery (HR) population in Bangladesh were identified in this study. A total of 6780 differentially expressed genes (DEGs) in HL compared to HR indicated significant variations in gene expression consistent with habitat-ambitious transcriptional divergence. Gene ontology and KEGG pathway revealed that HL was characterized by enhanced growth and energy-related processes, including ribosome pathways, ATP biosynthesis, cell cycle regulation, and oxidative phosphorylation compared to HR and PD. Conversely, PD showed enrichment in the nucleotide, cofactor and carbohydrate metabolism pathways, suggesting higher metabolic efficiency under natural environmental conditions. In contrast to wild populations, HR was enriched by endocrine, immune and stress-related pathways, including ATPase regulatory molecular function and pathogen-associated signalling, suggesting elevated physiological stress in the hatchery environment. Overall, wild populations showed enhanced metabolic efficiency and growth, while the hatchery population displayed reduced metabolic performance and heightened stress responses. These findings showed habitat fragmentation influenced the growth, metabolism and stress response in both wild and hatchery population, where the different environmental factors shape the population's genetics and different biological pathways, which made the wild population unique and more suitable for improving breeding programs, boosting aquaculture productivity and ensuring the aquaculture sustainability of this important fish species in Bangladesh.

This study investigates the widespread degradation of river ecosystems in Bangladesh and its impact on fish biodiversity and identifies potential strategies for ecosystem restoration. Combining community perceptions from focus group discussions (FGDs) with fish market study for spatial analyses of fish species diversity across the Barak–Meghna, Brahmaputra–Jamuna and Ganges–Padma basins, the research identifies pollution, destructive fishing practices, habitat destruction and mismanagement of water bodies as major threats. Results from 36 FGDs indicated that pollution from poultry farms, industrial waste from factories and pesticide runoff from agriculture were major contributors to the degradation of the Barak–Meghna basin, collectively affecting fish biodiversity. Fish market study identified a total of 57 fish species across the basins, far fewer than the over 260 species known to inhabit the freshwaters of Bangladesh. The Shannon–Wiener Diversity Index revealed low indices in Dhaka (0.00) and Rajshahi (1.73), signifying ecological degradation and anthropogenic stress, respectively, while Chandpur (2.52) and Pabna districts (2.30) exhibited comparatively higher diversity, pointing to potential conservation hotspots. The study highlights the perceptions of declining fish biodiversity with the percentages of FGDs reporting a decline of 83.3%, 90.9% and 91.7% in Barak–Meghna, Brahmaputra–Jamuna and Ganges–Padma basins, respectively. The study recommends an integrated approach combining physical interventions like collaborative dredging of rivers with pollution control measures, strengthened fisheries governance, community-based co-management, equitable water body leasing policies and transboundary coordination to ensure sustainable river restoration and biodiversity conservation.

Tank colour is a crucial environmental factor that influences growth performance; however, its effect on Channa striata fry under laboratory environments is not widely recognized. This study investigated the influence of tank coloration on growth, survival, cannibalism, and pigmentation of C. striata larvae under nursery rearing conditions. A 35-day rearing trial was conducted using five treatments: control, white, black, blue, and red, each in triplicate. Larvae were fed trash fish paste and live feed at 5%–10% of body weight three times a day and adjusted weekly. Growth and survival differed significantly (p < 0.05) among treatments. The results showed that fish reared in blue and white tanks achieved the highest final lengths (7.57 ± 0.88 cm and 7.32 ± 0.52 cm) and weight gains (3.40 ± 0.19 g and 3.18 ± 0.21 g), along with favourable feed conversion ratios. Survival rates were the highest in the white and blue colour tanks, whereas the control group exhibited the lowest survival rate. Cannibalism significantly decreased in blue and white tanks, while it remained high in the black and control treatments. Pigmentation assessment showed that tank background affected skin colour, with blue tanks having the highest hue angle and red tanks having the highest chroma value. The findings suggest that the rearing of C. striata larvae in blue and white tanks can considerably enhance growth and survival, providing a feasible and cost-effective technique for improving the quality of seeds and the efficiency of production in snakehead aquaculture.

Despite the large perceived popularity of fishing as a recreational activity, its multiple tourism dimensions, such as constraints, have received somewhat limited research interests. Leisure constraints research sheds insights into consumer travel, helping tourism service providers and developers develop and target services more efficiently. Exploring why people seek or avoid destination activities, such as recreational fishing, helps craft strategies to address these constraints and modulate participation. This study examines the leisure constraints of recreational fishing within a tourism context by exploring both participants' and potential participants' perceived and experienced constraints in activity participation. Employing a case study approach, the study investigates the Russian tourists' constraints in recreational fishing activities in Finland, including an examination of water quality as a constraint in their fishing activities. Research panel data from 465 Russian tourists who had visited Finland suggests that leisure constraints vary across recreational fishing participants and potential participants. Russian tourists who had fished in Finland noted constraints related to language skills and fishing expenses. For those who had not fished, intrapersonal and structural constraints, namely, ‘knowledge about Finnish fishing environment’ and ‘service provider information’ were the strongest ones. Respondent's language skills were the highest rated constraint across both participants and potential participants. While female participants were generally more constrained than male participants, a closer look at gender among potential participants showed that males were more constrained across several constraints. The study shows the relevance of examining a group of potential participants to pinpoint their constraints and needs. Based on the results, easier accessibility regarding fishing related information would likely help international tourists ‘go fishing’ during their trip.

Aquaculture is the fastest-growing sector of animal food production, yet it faces increasing challenges in maintaining fish health and sustainability due to the widespread use of antibiotics and synthetic feed additives. Green tea (Camellia sinensis), a natural source of polyphenols and bioactive compounds, has gained attention as a functional feed additive capable of enhancing growth performance, immune function and disease resistance in aquaculture species. This review critically examines genomic and omics-based evidence supporting the efficacy of C. sinensis in fish and shrimp nutrition. Findings from quantitative PCR (qPCR) and transcriptomic studies reveal that green tea supplementation significantly modulates the expression of key immune and antioxidant genes, including IL-1β, TNF-α, SOD and CAT, thereby strengthening innate immune responses and oxidative stress resistance. In addition, green tea influences critical stress and pathogen-response pathways through the upregulation of HSP70, toll-like receptors (TLRs) and activation of the NF-κB signalling cascade. These molecular responses collectively contribute to enhanced physiological resilience and reduced reliance on antibiotics. Comparative data indicate consistent improvements in growth metrics, gene expression profiles and immune biomarkers across multiple aquaculture species, emphasizing dose specificity and conserved pathways across species. The integration of green tea into aquafeeds presents a sustainable, eco-friendly strategy aligned with modern functional feed innovations. Future research should aim to optimize dosage levels, evaluate species-specific responses and employ integrative multi-omics approaches to further elucidate long-term effects on aquatic health and environmental sustainability.

Coastal communities in Bangladesh face significant challenges due to long-term salinity intrusion, leading to economic vulnerability and environmental stress. The remarkable adaptability of mud crabs to saline environments has encouraged coastal farmers to transition from shrimp aquaculture to mud crab fattening as an adaptive strategy. However, the sustainability of this practice is challenged by the overexploitation of wild seed, elevated mortality rates, suboptimal stocking densities and lack of standardized hatchery-produced crablets. Therefore, the present study aimed to evaluate the growth performance and survival of juvenile mud crabs (Scylla olivacea) reared at three different stocking densities (2, 4 and 6 crab/m²) randomly allocated in triplicate earthen grow-out ponds over a 90-day culture period. Hatchery-reared juvenile mud crabs (1.78 ± 0.18 g) were stocked into 80 m² earthen ponds, where Nypa palm (Nypa fruticans) leaves were used as shelters covering 30% of the pond area. Survival rate, growth performance and key physicochemical parameters were monitored throughout the culture period. Principal component analysis (PCA) was also done to explain other factors that may influence the growth performance of crabs during culture. Crabs were fed once daily in southwestern areas with experimentally formulated feed with 45% protein. The findings revealed that stocking density significantly affected (p < 0.05) the survival rate. Crablets stocked at 2 and 4 crab/m² had a significantly (p < 0.05) higher final mean weight than crablets stocked at 6 crab/m². Crabs reared at a moderate stocking density (4 crab/m²) demonstrated higher yields than other treatments. Stocking with 6 crab/m² exhibited the higher number of deformed crabs. These results indicate that a stocking density of 4 crab/m² is recommended for the grow-out of S. olivacea crablets in earthen ponds. Optimal stocking density will provide scientific basis to enhance production efficiency, reduce mortality and promote sustainable mud crab aquaculture in Bangladesh.