Aquaculture Research最新文献

To be economically viable and improve welfare, innovative feeding regimes are imperative for achieving high growth and survival rates in gilthead seabream larval production. In a gilthead seabream (Sparus aurata) larvae trial, we compared four novel feeding regimes to the standard diet (Std-Art), which included consecutive feeding of Brachionus plicatilis (Rot) and Artemia salina (Art) from 4 days post-hatching (dph) until weaning at 32 dph, followed by microdiet (MD) until 56 dph. All newly formulated feeding regimes included MD mostly from first-feeding, with variations in live feeds provided. The first regime included initial consecutive feeding of Acartia tonsa nauplii (Cop) and then Artemia until weaning at 26 dph (MDe-Cop-Art). The second regime involved rotifer feeding until 20 dph (MDe-Rot), while the third provided A. tonsa until 20 dph (MDe-Cop). The fourth regime featured consecutive feeding of two copepods species, the regularly used A. tonsa and a newly tested tropical species, Apocyclops panamensis (from nauplii to copepodite) until 20 dph, introducing MD at 18 dph (MDa-2Cop). The MDe-Cop-Art regime substantially outperformed all other regimes in survival rate (37.5% ± 2.7% vs. 21.1% ± 2.7% of Std-Art) and total biomass production per tank (69 ± 7 g vs. 16 ± 7 g of Std-Art). This highlights the advantage of feeding copepods over rotifers and emphasises the importance of a short Artemia inclusion, potentially improving feeding activity, digestion and assimilation. Co-feeding live feed with MD from first-feeding was found to enhance growth and survival, indicating the progressive adaptation of larvae to the physical and biochemical characteristics of the MD. This adaptation likely promoted earlier maturation of the digestive system and improved nutrient uptake and utilisation. Considering the overall growth and survival performance, the incorporation of MD from first-feeding, coupled with A. tonsa and followed by a short Artemia feeding is highly recommended for gilthead seabream larvae commercial rearing.

Smallholder fish farmers in Zambia face complex social and ecological challenges. Previous studies have highlighted limitations to productivity in Northern Province, where rates of poverty are high and farmers lack access to essential inputs and markets. Stakeholders emphasize research is needed to understand aquaculture’s functions at household and farm scales. Innovations to improve productivity must consider agroecological contexts, local knowledge, and adaptations to situate aquaculture within local livelihood. A study was conducted in Luwingu District to assess productivity and understand farmer perceptions. Data collection (Oct–Dec 2021) engaged fish farmers (n = 63) in surveys, farm appraisals, and discussions. Qualitative data highlighted farmers’ perspectives, and thematic review identified their major challenges. Quantitative data described household demographics, priorities, resources, and management systems. Multivariate techniques (principal components analysis [PCA]) assessed variation within the sample, reduced data complexity, and created sets of composite variables describing system inputs. Multiple linear regression tested effects of inputs on pond productivity (kg Fish m⁻²); and stepwise elimination identified key factors. Results indicated that farmers considered aquaculture a secondary economic activity, contributing an average of only 9% ± 12% to household income. Most farmers used household labor, basic tools, and crop waste as inputs. The mean output (1.2 ± 1.2 t fish ha⁻¹) was low. Predictive models indicated household wealth, education, farm size, intensity of feed, fingerling and labor inputs, fish growth cycles, and spatial integration with cropland were most associated with aquacultural productivity. Farmers emphasized that limited finances, high costs, and inconsistent local supplies of quality inputs were major challenges. Potential pathways for change are discussed, and recommendations for additional research are offered.

This study investigated the impact of varying concentrations, including 0.5 mg L⁻¹ (T₁), 1 mg L⁻¹ (T₂), and 2 mg L⁻¹ (T₃) of zinc oxide nanoparticles (ZnO NPs) on hematological, biochemical, and histological indices of Cyprinus carpio. As the use of ZnO NPs grows, there are rising concerns about their potential environmental impacts, particularly on aquatic ecosystems. When released into water bodies, these NPs can be ingested by aquatic organisms, leading to bioaccumulation and potential toxicity. Therefore, understanding their effects on aquatic species, like C. carpio, is crucial. Significant alterations in the erythrocyte count, hemoglobin (Hb), and hematocrit (Ht) levels were found. Compared to the control group, the number of lymphocytes, EOSO, monocytes, and platelets in the Zn NPs-exposed groups dramatically increased. The biochemical analysis found considerable changes in blood total protein, albumin, globulin, and glucose levels. Histological examinations of the gills, intestines, and kidneys were conducted to assess structural or pathological changes. Treated fish showed progressive architectural distortions like necrosis (N), hyperplasia (HP), hypertrophy (HT), fusion of gill lamella (FGL), and proliferation of mucocytes (PM) in gills. Distension of the intercellular space (DIS), increased rate of the mucous cell (IMC), villous atrophy (VA), HP, and dysplasia (DP) were found in the intestines of ZnO NPs treated C. carpio. Tubular dilatation, tubular necrosis, severe congestion, hematopoietic tissue degradation, constricted lumen, glomerulopathy, and bowmans capsule dilution in kidneys of ZnO NPs treated C. carpio were noted. The findings from this study shed light on the biochemical and histological effects of ZnO NPs on C. carpio, contributing to a better understanding of the potential risks associated with NP exposure in aquatic environments. The results highlight the need to regulate the use of these NPs as well as their disposal in order to reduce the potential impact that they could have on aquatic ecosystems and public health.

Apostichopus japonicus is a commercially important marine species known for its high nutritional value and a range of bioactive compounds, including polysaccharides, collagen, and saponins. In this study, a genome-wide association study (GWAS) was carried out on 143 A. japonicus individuals. A total of 72 single nucleotide polymorphisms (SNPs) and 36 candidate genes were identified through the analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were then conducted, leading to the identification of 10 candidate genes related to polysaccharide, collagen, and saponin traits. These candidate genes were further validated through subsequent analyses. Five candidate genes, ALDH5A1, FAT1, KDR, ORC2, and PIGK, were identified to affect polysaccharides synthesis, among which the SNPs of ALDH5A1 had nonsynonymous substitution (S12G). BMI1 and UBR4 were identified as key candidate genes for collagen synthesis. A nonsynonymous SNP at Chr7_28028124, although not annotated to a known gene, was located within an exon and resulted in a serine-to-cysteine (S→C) substitution, which may influence collagen synthesis by affecting the function of an uncharacterized protein. CUBN and structural maintenance of Chromosomes 1B (SMC1B) were identified as candidate genes associated with saponin synthesis. The SNPs and candidate genes identified in this study serve as valuable genetic resources for selective breeding in A. japonicus and contribute to a better understanding of the genetic basis of these traits.

Oxygen is typically one of the first limiting water quality parameters affecting the culture of aquatic animals. However, there is a limited understanding of the effects of short-term low dissolved oxygen (DO) in Pacific white shrimp reared in outdoor green-water environments exposed to natural diurnal cycles, especially less than 3 mg L⁻¹ DO, and their impacts in commercial aquaculture settings. The present study evaluated the effects of cyclic short-term low DO conditions in outdoor green water tanks on shrimp survival, growth, nutrient retention, select blood parameters, and gene expression of the gill and hepatopancreas. The experiment was performed in 12 (800 L, 0.8 m²) round tanks stocked at 35 shrimp m⁻² (1.99 ± 0.06 g) using three aeration regimens. Four tanks were assigned to each treatment which included: low, medium, and high aeration using 0.25, 0.35, and 0.7 cubic feet per second (cfs) airstones, respectively. Diurnal cycles were allowed to cause varying periodic periods of short-term low DO. We found no difference in shrimp growth, survival, feed utilization, blood parameters, or gene expression of shrimp maintained in systems where DO was maintained near saturation as compared to those experiencing diurnal shifts in DO and nonlethal short-term low DO conditions. Clearly, lethal levels of DO must be avoided but we did not find justification to maintain DO in diurnal systems near saturation throughout the diurnal cycle.

The bacterial pathogens Aeromonas species, notably Aeromonas veronii and Aeromonas hydrophila, are major causative agents of severe infections and significant mortalities in freshwater aquaculture systems. Vaccination offers an effective prophylactic approach to enhance fish immune defenses and reduce reliance on antibiotics. This study aimed to evaluate the immunoprotective efficacy of a bivalent bacterial oral vaccine against these pathogens in carps. The vaccine was formulated by either incorporating or spraying it/onto commercial feed (30% crude protein), with 10% fish oil and mineral oil added as adjuvants. Seven experimental dietary diets were designed, comprising vaccinated feeds administered with or without adjuvants (1 mL of vaccine per gram of feed) and a nonvaccinated control. Healthy fingerlings (20 ± 5 g) were fed their respective diets over a 60-day experimental period, followed by challenge with Aeromonas spp. To evaluate the effectiveness of the vaccination, immune parameters (serum lysozyme activity, agglutination antibody titers, and IgM levels), growth performance (net weight gain [NWG], specific growth rate [SGR], and feed conversion ratio [FCR]) and survival rates were examined. In comparison to the control, the results indicated that all vaccination diets showed considerably improved immune responses and growth. However, vaccinated diet with fish oil (IVFF) showed the highest immunological stimulation and rate of survival, 83% for Ctenopharyngodon idella (C. idella) and 85% for Labeo rohita (L. rohita). These results validate the IVFF oral vaccine formulation has potential as a noninvasive, scalable method of providing protective immunization against Aeromonas infections in freshwater aquaculture.

Choline, an essential nutrient for aquatic animals, plays an important role in fish growth performance and health, but its effect on bighead carp is not yet known. To investigate the effects of choline chloride on growth performance, antioxidant properties, and intestinal function of juvenile bighead carp (Aristichthys nobilis), fish with an average weight of 1.77 ± 0.20 g were fed with different dietary choline chloride supplementation concentrations: 0 g/kg (control), 2, 4, 6, 8, and 10 g/kg for 66 days. The results indicated that dietary choline chloride supplementation at 6 g/kg improved the weight gain rate (WGR) and specific growth rate (SGR) (p < 0.05). Dietary choline chloride supplementation (4–10 g/kg) decreased serum in serum triglycerides (TGs), total cholesterol (T-CHO), and glucose (GLU) levels of juvenile bighead carp (p < 0.05). The malondialdehyde (MDA) level was significantly lower than the control group when choline chloride supplementation ranged from 6 to 10 g/kg. When choline chloride supplementation was at 6 g/kg, the activities of catalase (CAT) and superoxide dismutase (SOD) were significantly higher than the control group (p < 0.05). The levels of choline chloride supplementation (6–10 g/kg) increased the activity of intestinal digestive enzymes and enhanced the intestinal digestibility of juvenile bighead carp (p < 0.05). In addition, choline chloride levels did not affect the abundance of intestinal microbiota, and the composition of the dominant phylum genera was similar, including Ascomycetes, Actinobacteria, and thick-walled bacteria. At the genus level, there are Gemmobacter, ZOR0006, Peredibacter, and Mycobacterium, respectively. Overall, choline chloride supplementation (4–10 g/kg) could significantly improve the growth performance, antioxidant capacity, and digestive enzyme activity of juvenile bighead carp. Furthermore, broken-line regression analysis has identified 6.51 and 6.62 g/kg as the optimal levels of dietary choline chloride for juvenile bighead carp based on growth performance. Overall, appropriate dietary choline chloride could improve growth performance, antioxidant capacity, and intestinal function in bighead carp.

This study aimed to assess the survival and growth rates of Yesso scallop Mizuhopecten ( = Patinopecten) yessoensis spat transplanted from the East Sea and cultured in both inner and outer areas of Goseong Bay, Korea, using idle Bay scallop (Argopecten irradians) aquaculture facilities during the off-season (November–June). Additionally, economic feasibility of this cross-cultivation approach was evaluated. Yesso scallop spat with a mean shell length of 17 mm were stocked in lantern nets in both inner and outer areas of Goseong Bay in October 2020 and monitored monthly until June 2021. Environmental parameters, including surface seawater temperature (SST), dissolved oxygen (DO), and chlorophyll-a concentration, were continuously recorded. High survival rates (92%–100%) were observed at both sites, and scallops reached marketable sizes (shell length 62.0–65.0 mm; total weight 25.6–28.5 g) by June. The final shell length and total weight were 65.0 mm and 28.5 g in the inner bay, and 62.0 mm and 25.6 g in the outer bay, respectively; although these differences were statistically significant, the overall size and weight achieved in both areas were similar and commercially acceptable. Economic analysis demonstrated a return on sales (ROS) of 49.8% and a benefit–cost ratio (BCR) of 2.0 for Yesso scallop cross-cultivation, exceeding those of conventional Bay scallop monoculture. These findings indicate that utilizing existing aquaculture infrastructure for Yesso scallop production during the Bay scallop off-season is both biologically viable and economically advantageous, providing a practical strategy for optimizing facility use and revitalizing Yesso scallop aquaculture in Korea.

Sustainable Development Goals (SDGs) provide a global framework for achieving economic, social, and environmental sustainability by 2030. Despite Bangladesh being one of the leading aquaculture-producing countries, no comprehensive study has examined the contributions of aquaculture to achieving the SDGs. This comprehensive review-based study demonstrates that aquaculture in Bangladesh contributes to nearly all SDGs through direct, indirect, related, and associated pathways. In 2022–2023, Bangladesh produced 4.9 million MT of fish, with aquaculture accounting for 58.03% of total production. Aquaculture production strengthens food security (SDG 2) and health (SDG 3) by providing nutrient-rich fish, particularly small indigenous species (SIS), which supply essential micronutrients. Through income generated from aquaculture farming in rural areas, farmers significantly improved infrastructure for drinking water and sanitation facilities (SDG 6) and reduced dependance on polluted water sources. The sector also fosters decent work and economic growth (SDG 8) by creating employment opportunities across production, processing and trade, reducing poverty (SDG 1), and economic inequality (SDG 10). Environmentally, aquaculture contributes to climate action (SDG 13) by adopting low-carbon farming techniques, such as pond fish-vegetable, integrated rice-fish, and rice-fish-vegetable farming. It protects life below water (SDG 14) by reducing overfishing and conserving marine biodiversity, while promoting responsible consumption and production (SDG 12) through sustainable feed innovations and waste management. Additionally, aquaculture enhances sustainable cities and communities (SDG 11) by ensuring a stable fish supply for urban populations and supporting rooftop and peri-urban aquaponics. It also strengthens peace and partnerships (SDG 16 and 17) to an extent by fostering collaboration among government bodies, private enterprises, and research institutions. Future research should prioritize climate-resilient fish farming, cost-effective aquaculture, and AI monitoring while strengthening value chains, export access, governance, public–private partnerships, and renewable energy to ensure sustainable aquaculture growth and broader SDG achievement.

Scallops are highly prized shellfish in the North Yellow Sea and are primarily harvested using trawling methods. However, this harvesting method has resulted in the incidental bycatch of other benthic organisms, negatively impacting the seafloor ecology, and ultimately hindering the sustainable development of the scallop industry. To mitigate these issues, modifications were proposed, including an adjustable hydraulic plate, flexible connections, and elastic components to reduce damage, sediment content, and bycatch. Key causes, including net gear leakage, rigid teeth injuries, and sediment disturbance, were identified through underwater monitoring and hydrodynamic analysis. Simulations of various hydraulic plate designs have revealed optimal parameters for minimizing drag resistance and maximizing efficiency, with the negative-angle-arc plate demonstrating superior performance under specific conditions. Optimal trawling parameters, including rope lengths, drag forces, and angles, were established for towing speeds ranging from 1.5 to 2 m/s at depths of 30–50 m. Setting the net opening at 350 mm, below the rising current height of the hydraulic plate, was found to effectively increase scallop harvests, while reducing bycatch of benthic fish. These findings provide actionable insights for sustainable scallop trawling practices.