Aquaculture International最新文献

Gim (Pyropia yezoensis) is Korea’s most commercially important marine product, supplying over 80% of global demand and sustaining coastal livelihoods. Its export value has risen from USD 100 million in 2010 to nearly USD 1 billion in 2024, underscoring its economic importance. Yet Gim cultivation is highly sensitive to environmental variability and increasingly vulnerable to climate stress. This study analyzes the effects of seawater temperature, rainfall, sunlight duration, and wind speed on Gim production using 8 years of monthly data (2016–2023) from Wando, South Korea’s leading production site. A second-degree polynomial regression with 1-month-lagged rainfall and sunlight duration was applied to capture nonlinear and delayed ecological responses. Results show that seawater temperature is the dominant driver. Yields peak within a narrow 10–15 °C thermal window but decline at both cooler and warmer extremes. Wind speed also exerts nonlinear effects, enhancing growth under moderate conditions but reducing yields at higher intensities. Rainfall and lagged sunlight duration contribute positively but more weakly, emphasizing the role of joint ecological interactions rather than single drivers. In the short term, adaptive strategies such as optimized seeding schedules and expanded land-based seeding systems could stabilize yields. Long-term measures should prioritize breeding heat-tolerant strains, diversifying cultivation sites, and investing in technological innovation. Although limited to Wando, the findings provide robust evidence of Gim’s climate sensitivity and offer practical guidance for improving the resilience and sustainability of seaweed aquaculture under changing conditions.

Mud crab aquaculture (genus Scylla) has expanded substantially across Southeast Asia in response to increasing market demand and improvements in hatchery and grow-out production systems. Despite this expansion, the sector continues to face environmental, economic, and genetic constraints that affect production stability and long-term sustainability. Existing studies commonly address these issues separately, with limited integration across production stages and management contexts. This review evaluates current knowledge on the major challenges affecting mud crab aquaculture, including habitat degradation, water quality deterioration, disease outbreaks, high production costs, market volatility, labor intensity, and reduced genetic diversity. Evidence across hatchery, nursery, and grow-out systems indicates that environmental stressors influence disease occurrence and survival, while economic pressures limit investment in biosecurity, feed improvement, and technological adoption. In addition, reliance on wild-sourced broodstock and insufficient genetic monitoring may reduce adaptive capacity in cultured stocks. By organizing these findings within a production-stage perspective, this review highlights common constraints, identifies practical management implications, and outlines directions for strengthening coastal governance, broodstock management, and technological adoption. The synthesis aims to support more coordinated approaches to sustainable development in mud crab aquaculture.

Freshwater integrated multi-trophic aquaculture (IMTA) systems are increasingly used to enhance nutrient utilization efficiency; however, their performance under microplastic (MP) exposure remains poorly characterized. This study evaluated the effects of water-borne and feed-borne polyethylene (PE) MP (10–20 µm) on biomass production and filtration performance in a three-compartment freshwater IMTA system comprising rainbow trout (Oncorhynchus mykiss), freshwater mussels (Unionidae), and duckweed (Lemna minor). Fluorescent spherical MPs were applied in four treatments (n = 3 tanks per treatment): control (no MPs), feed-borne MPs (5 particles per 100 g feed), water-borne MPs (35 particles L⁻¹ at fish-tank inflow), and combined exposure. The exposure phase lasted 45 days with 15-day sampling intervals, followed by a 45-day depuration phase. Fish growth responses differed modestly among treatments during exposure, with transient reductions observed in MP-exposed groups relative to the control at intermediate sampling points. Mussel filtration capacity showed limited variation among treatments, with no consistent treatment-specific suppression across time. Duckweed biomass accumulation was lower under combined exposure compared with the control, whereas variability was higher in MP treatments during early growth stages. An integrated multi-trophic performance index calculated from terminal measurements indicated moderate reductions in overall system productivity under combined exposure relative to the control. During depuration, growth trajectories across treatments converged. These results indicate that elevated microplastic exposure can influence biomass distribution and productivity within freshwater IMTA systems, particularly under combined exposure scenarios.

Previous studies on the optimal protein requirements of freshwater crayfish Cherax quadricarinatus juveniles have mainly focused on growth performance, with limited attention to nutritional physiology and changes in the intestinal microbiome. This study evaluated the effects of reduced dietary protein levels (25%, 30%, 35%, and 37%) on digestive enzymes, energy reserves, hemolymph metabolites, intestinal microbiome, and hepatopancreas histology of juveniles fed for 150 days. The experimental diets were formulated using fish and shrimp meals as animal protein sources, and wheat, rice meals, and cornstarch as plant ingredients. While growth and survival were unaffected by dietary protein, juveniles fed the 25% diet showed reduced lipase activity, increased hepatopancreatic lipid content, lower glycogen reserves, and higher hemolymph glucose concentration. These changes in nutritional physiology were likely influenced not only by dietary protein level but also by interactions among the ratios and sources of dietary protein, lipids, and carbohydrates. The intestinal microbiome of juveniles fed the 25% diet exhibited shifts in bacterial communities and an overall reduction in 20 metabolic pathways. Our results support the use of a diet with 25% crude protein in C. quadricarinatus culture during these early stages, at least temporarily, offering potential economic benefits by reducing feed costs without compromising productive efficiency. This study expands our understanding of the deployed physiological strategy and contributes to the development of balanced diets for juveniles, but also provides new insights into changes in the intestinal microbiome of the species when fed different protein diets.

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The development of efficient and sustainable diets for sea cucumber aquaculture is critical to support the growth of this emerging sector. This study evaluated the effects of four experimental diets (D1 to D4) on juvenile Apostichopus parvimensis during a 4-week feeding trial conducted in triplicate. The experimental diets differed in their main ingredient profiles: D1 was based on fish organic residues (FOR); D2 used a fishmeal–soybean meal–wheat meal mixture; D3 included a brown seaweed meal mix as a wheat meal substitute; and D4 combined higher fishmeal inclusion with the same brown seaweed meal mix. Sea cucumber performance parameters (final weight, weight gain, and specific growth rate), survival, dry body weight, feed conversion ratio (FCR), and digestive enzyme activities (trypsin, lipase, amylase) were measured and analyzed using one-way ANOVA and Tukey’s test. The D4 diet led to the highest FW and SGR, yet exhibited significantly lower dry body weight and a tendency to a lower FCR. Diets D2 and D3 resulted in significant trypsin activity compared to D1 and D4. Diet D2 showed the highest lipase activity but the lowest trypsin activity. Amylase activity was significantly reduced in D4, likely related to the presence of complex seaweed polysaccharides. Overall, these findings provide insight into the effects of dietary ingredients such as FOR, brown seaweeds, and spirulina on growth and digestive physiology of juvenile sea cucumbers, contributing to the development of sustainable diet formulations. Highlights. The study evaluates different feed formulations for juvenile Apostichopus parvimensis. A diet combining fishmeal and brown seaweed (D4) yielded the highest growth performance. Spirulina inclusion enhanced dry matter deposition and trypsin activity. Wheat meal–based diet (D2) led to higher lipase but the lowest trypsin activity. Fish organic residues and spirulina show promising potential for juvenile A. parvimensis diets.

Greenhouse gas (GHG) emissions from coastal aquaculture are an emerging environmental concern, with implications for ecosystem sustainability and climate mitigation. In this preliminary field-based study, we quantified carbon dioxide (CO₂), methane (CH₄), and nitrous dioxide (N₂O) fluxes from 35 randomly selected prawn farms in coastal Bangladesh, at a single time point using the floating chamber method, with concurrent water quality monitoring and farm management surveys, to identify key factors influencing in-pond GHG emissions. Extensive farming systems showed a higher CO₂ emission rate (1261.3 ± 727.0 g/ha/day) than semi-intensive farms, while CH₄ (10.3 ± 5.60 g/ha/day) and N₂O (0.71 ± 0.53 g/ha/day) fluxes were higher in the semi-intensive farms. The total GHG emissions (CO₂ equivalent; CO₂e in a 100-year life span) were lowest in semi-intensive farms (898.3 ± 245.7 g/ha/day). Correlation analysis revealed significant negative associations between total CO₂e emissions and salinity, feeding frequency, and carp stocking density, while standing crop showed a positive association. Random forest modelling further revealed that pond biomass, salinity, and feeding rate were important predictors of CO₂, whereas CH₄ and N₂O were primarily determined by water age and water source, respectively. Although this preliminary study was limited by the number of sampled farms and the temporal resolution of sampling, it cautiously proposes frequent water exchange, stocking-density optimization, carp integration, increased feeding frequency, and enhanced farmers’ knowledge as possible options to reduce emissions but warrants further longitudinal investigation.

The use of natural immunostimulants as alternatives to antibiotics has gained attention in aquaculture to mitigate disease impacts. In this study, we evaluated fucoidan extracted from giant bull kelp (Durvillaea potatorum) as a dietary additive in black tiger shrimp (Penaeus monodon). Four experimental diets containing increasing levels of fucoidan (0, 1.0, 2.5, and 5.0 g kg⁻¹ diet) were tested for their effects on growth, non-specific immune parameters, and survival against white spot syndrome virus (WSSV) and acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus. After 30 days of feeding, fucoidan supplementation did not adversely affect shrimp growth or culture survival, even at the highest inclusion level (5 g kg⁻¹). Non-specific immunological indices, including total hemocyte count (THC), differential hemocyte count (DHC), phenoloxidase (PO) activity, plasma total protein (PTP), and plasma agglutination titer (PAT), were enhanced by fucoidan supplementation, with improvements observed even at 1 g kg⁻¹ relative to the control group. Activation of non-specific immunity translated into increased resistance against WSSV and AHPND, with the highest survival recorded in shrimp fed 5 g kg⁻¹ fucoidan, followed by 2.5 g kg⁻¹. In comparison, similar survival rates against WSSV and AHPND were observed in the unsupplemented control and 1 g kg⁻¹ fucoidan. Overall, this study demonstrates that dietary inclusion of D. potatorum fucoidan at 5 g kg⁻¹ effectively enhances immune responses and disease resistance in P. monodon without negatively impacting growth performance, highlighting its potential as a functional feed additive in shrimp aquaculture.

Litopenaeus vannamei, a key species in global aquaculture, shows excellent growth and adaptability, making it central to shrimp farming. As genetic improvement progresses, the genomic characteristics of L. vannamei populations continue to evolve. To clarify their genetic status, we analyzed selection signals using resequencing data and environmental factors, identifying adaptive genomic regions. In this study, offspring were produced by hybridizing six L. vannamei populations (two breeding and four introduced). The offspring were subjected to ammonia nitrogen and low pH stress experiments, and extreme difference groups were established based on survival time under stress. Whole-genome resequencing was performed on the six original populations and stress groups (320 individuals). After quality control, 17,104,219 high-quality SNPs were obtained. Using the multi-reference population rotation method, we identified population-specific selection regions in six L. vannamei populations through F_st and θπ ratio analyses. Functional enrichment revealed multiple cross-functional modules and conserved genes across populations. This distribution indicates that L. vannamei adaptive evolution features both population differentiation and conservation of core pathways. Further multi-method joint analysis using F_st, θπ ratio, and XP-CLR identified 356 (ammonia nitrogen) and 370 (low pH) candidate genes in the stressed populations. After GO/KEGG annotation, selection signal screening, and ROH detection, five core stress response genes, including Vang and Coq8. Genome-wide selection signal analysis in L. vannamei populations revealed key functional genes, thereby enriching genetic resources and facilitating the breeding of new varieties.

In recirculating aquaculture systems, dissolved oxygen and water temperature are two critical water quality indicators that must be maintained within suitable ranges. However, due to the strong coupling between their control processes, regulating only one of these variables makes it difficult to ensure an optimal water environment. To address this issue, a state-space equation-based model predictive controller (MPC) was designed for decoupling control of dissolved oxygen and water temperature. This method first establishes differential equations that can describe the dynamic response characteristics of dissolved oxygen and water temperature, thereby exploring the coupling relationship between them. Subsequently, system identification is employed to transform the established differential equations into a set of state-space equations, which serve as the internal predictive model of the MPC, thereby reducing the computational load while simultaneously enhancing control accuracy and decoupling performance. To verify the reliability of the proposed MPC, tracking control experiments were conducted in both simulated and real aquaculture environments, with the results demonstrating that MPC outperforms the proportional integral differential (PID) controller in both scenarios. Specifically, MPC can maintain a tracking error range of ± 0.4 mg/L for dissolved oxygen and ± 0.15 °C for water temperature in real aquaculture environments, and its control outputs (airflow and hot water flow) are relatively small compared to traditional PID controller. These results further demonstrate that the proposed MPC offers the advantages of strong stability and significant energy savings, making it particularly well suited for multivariable water quality regulation in recirculating aquaculture systems.

Since the late 1980s to 2025, at least 16 disease entities have been reported to affect commercially cultivated seaweeds, occurring in both open-water farming systems and nursery facilities. The expansion and intensification of seaweed production have increased the frequency of host–pathogen interactions, a trend further exacerbated by environmental stressors associated with climate change, including ocean warming, salinity fluctuations, and acidification. These conditions have contributed to rising disease incidence, with consequences such as reduced yields and product quality, greater economic losses, and a potential weakening of the overall resilience of the seaweed industry. This review was conducted using a systematic literature review approach by compiling and screening scientific publications from Scopus, Web of Science, SpringerLink, and two additional relevant sources to provide a comprehensive synthesis. Based on the evidence assembled, this review aims to (i) map the relationships between biotic and abiotic factors and the emergence and spatial distribution of diseases across seaweed species and cultivation regions, (ii) examine the economic consequences of disease along the seaweed value chain, and (iii) evaluate key aspects of disease management in seaweed aquaculture systems. Overall, this review provides a scientific basis for shaping research and policy agendas that prioritise risk-based biosecurity, the development of tolerant varieties, early-warning systems and rapid diagnostics, high-resolution environmental monitoring, and strengthened collaborative governance through public–private partnerships to support sustainable and disease-resilient seaweed aquaculture.