Aquaculture International最新文献

Developing a polyvalent vaccine strategy offers promising protection against diverse heterologous strains of Edwardsiella ictaluri. This study evaluated the efficacy and immune responses induced by an inactivated whole-cell polyvalent E. ictaluri vaccine, administered with or without a booster, in striped catfish (Pangasianodon hypophthalmus). Fish were vaccinated using inactivated polyvalent bacterin at concentrations of 10¹⁰ and 10⁹ CFU mL⁻¹. Vaccine performance was assessed through both specific and non-specific immune parameters and relative percent survival (RPS). The vaccine at 10¹⁰ CFU mL⁻¹ with a booster significantly enhanced antibody titers, phagocytic and lysozyme activities, respiratory burst, lymphocyte counts, and the expression of MHC class II and IL-1β genes. This formulation achieved the highest RPS values of 90.47%, 55%, and 60% against pathogenic E. ictaluri isolates PJbH, P, and PBm1G, respectively. In contrast, non-booster groups exhibited lower protection (RPS 61.90%, 42.85%, and 44.64%). In conclusion, the inactivated polyvalent vaccine at 10¹⁰ CFU mL⁻¹, with a booster, effectively strengthened both humoral and cellular immunity, providing robust protection against E. ictaluri infection in striped catfish.

Despite extensive coastline, the Kori Creek region of Gujarat faces significant challenges in fishing due to its strategic location near the India-Pakistan border. This study explores the feasibility of seaweed farming in the underexplored Kori Creek region, aiming to provide an alternative livelihood for local fishermen through seaweed cultivation. Feasibility experiments were carried out at three locations of Kori Creek: Narayan Sarovar, Pipar and Nani Cher. Kappaphycus alvarezii, a red alga, was grown using tube net method at all three locations for three consecutive cycles. The mean DGR ranged from 0.51 ± 0.18 to 1.22 ± 0.24% day⁻¹ at Narayan Sarovar, 1.86 ± 0.16 to 2.26 ± 0.35% day⁻¹ at Pipar, and 1.34 ± 0.25 to 1.91 ± 0.43% day⁻¹ at Nani Cher. Similarly, the mean yield per tube net varied between 0.11 ± 0.05 to 0.41 ± 0.19 kg fresh weight m⁻¹ at Narayan Sarovar, 0.40 ± 0.06 to 1.07 ± 0.14 kg fresh weight m⁻¹ at the Pipar and 0.34 ± 0.12 to 0.69 ± 0.24 kg fresh weight m⁻¹ at Nani Cher. Growth was found negatively correlated with seawater salinity at Nani Cher site. Yield showed positive correlation with phosphate while negative correlation with nitrite of the seawater of Pipar site. The semi refined carrageenan yield and gel strength were found in the range of 32.97 to 44.84% and 318 to 636 g cm⁻², respectively across all three sites. Economic analysis performed using single farmer model predicted Pipar as the highest profitable site with USD 2586, followed by Nani Cher with USD 1616 at actual selling price (USD 1.44 kg⁻¹) of raw K. alvarezii. Considering higher DGR, yield and good carrageenan properties, Pipar site was found most suitable site for commercial K. alvarezii farming in the Kori Creek region.

Accurately identifying the fish school feeding intensity is a critical step for implementing precision feeding in factory recirculating aquaculture systems (RAS). Fish exhibit a series of temporal dynamics during the feeding process, such as motion and instantaneous postural changes. However, existing single-modal visual methods for identifying fish school feeding intensity fail to efficiently capture temporal information from video, and are susceptible to severe environmental noise and water flow interference, resulting in misjudgment of feeding intensity. To this end, a dual-stream spatiotemporal fusion method (DSSFM) is proposed for fish school feeding intensity recognition. Firstly, a feature extraction network of MobileNetV3 is employed under the temporal segment network to extract features from RGB videos and optical flow map sequences. Then, the temporal connection module (TCM) is proposed to establish the inter-segment temporal correlations. Next, the cross-modality fusion module (CMFM) is proposed to achieve deep fusion of optical flow and RGB features, which introduces a selective state space model to model the inter-modality spatiotemporal consistency with linear efficiency. Within this module, the temporal enhancement bottleneck (TEB) block is proposed to focus on temporal information, including fish movement and direction information. To evaluate the proposed method, extensive experiments are conducted on the fish school feeding behavior video dataset. Experimental results demonstrate that our proposed method exceeds other mainstream single-modal and multimodal approaches, achieving a competitive performance in terms of accuracy (95.52%) and parameters (7.47 M). Therefore, the proposed method provides an effective solution for achieving high-precision, lightweight, and real-time recognition of fish feeding intensity in complex factory recirculating aquaculture environments.

Aquaculture wastewater contains high and variable suspended solids that require rapid and efficient clarification to protect receiving waters and cultured organisms. Coagulation–flocculation using plant-based coagulants offers a sustainable alternative to metal salts; however, existing studies are largely limited to seed-derived or non–freeze-dried materials and rarely address dosage efficiency or scalability. This study evaluates freeze-dried Moringa oleifera leaf extract as a low-dosage natural biocoagulant for aquaculture wastewater treatment. Protein–polysaccharide content and functional groups were characterized to assess preservation of coagulation-active constituents following freeze-drying. Coagulation performance was evaluated using jar tests in synthetic kaolin suspension and real aquaculture wastewater, followed by statistical optimization using response surface methodology (RSM). Optimal conditions achieved 71.0% total suspended solids (TSS) removal and 74.0% turbidity reduction at a low dosage of 0.03 g coagulant/g TSS. These results demonstrate that freeze-drying effectively concentrates functional biopolymers in leaf-based materials, enabling efficient coagulation at substantially lower dosages than commonly reported seed-based coagulants. The findings establish freeze-dried M. oleifera leaves as a stable, scalable, and chemically independent biocoagulant suitable for practical aquaculture wastewater treatment.

Taurine has been identified as a required nutrient in several Seriola species, whereas optimum dietary taurine (Tau) levels during the weaning period have not been yet determined in greater amberjack. Therefore, the effect of dietary Tau in microdiets for larval greater amberjack was determined by feeding 30 days post-hatching (dph) larvae with four microdiets containing 0.32 to 4.16% Tau levels for 2 weeks. Growth, survival, histology, skeletal anomalies, and expression of growth and stress-related genes were studied. Total length, weight gain, and daily weight gain of the larvae fed 1.39% Tau were higher than those of fish fed the other Tau levels. No differences were found in the larval health parameters studied, including intestinal integrity. Nevertheless, greater amberjack larvae fed 0.32 and 4.16% Tau showed a higher incidence of total severe skeletal anomalies. Moreover, dietary Tau increase up to 1.39% led to the upregulation of certain growth and stress-related genes (gh, igf2, and trh). These findings denote the importance of Tau levels in weaning diets to promote growth, cope with stress, and enhance bone health in larval greater amberjack, suggesting optimum levels around 1.39% Tau on a dry basis of diet.

Rapid and reliable on-site diagnostics, along with timely interventions, are vital for effective disease management. In this study, a multiplex LAMP-coupled lateral flow assay was developed for the simultaneous diagnosis of WSSV and EHP. The LAMP primers were designed to target the specific regions, envelope protein gene VP28 of WSSV and the spore wall protein gene (SWP) of EHP. To enable multiplex detection using lateral flow strips, EHP forward inner primer (FIP) and backward inner primer were labelled with biotin and FAM, at the 5’ end, respectively. While WSSV FIP and BIP were labelled with digoxigenin and FAM at the 5’ end. This multiplex LAMP was carried out using a simple dry bath and optimised at 65 °C. Following LAMP assay, the reaction mix was applied to the lateral flow strip. This multiplex LAMP (mLAMP) coupled with lateral flow dipstick (LFD) demonstrated high sensitivity, detecting as few as 10 copies of WSSV and 10 copies of EHP. This assay was rapid and can detect the disease within 58 min, including both amplification (55 min) and lateral flow readout time (3 min), excluding the DNA extraction step. This assay was observed to have 100% diagnostic sensitivity and specificity. This LAMP was highly specific and did not show any cross-amplification with other shrimp pathogens such as IMNV, IHHNV, Vibrios spp., or with host genomic DNA of Penaeus vannamei and Penaeus monodon. This multiplex LAMP coupled with lateral flow offers a rapid, sensitive, specific point-of-care diagnostic assay which can be used for routine on-farm surveillance.

As the aquaculture sector intensifies to meet global protein demands, optimizing feed quality through multifunctional feed additives becomes critical to sustain fish productivity with ecological responsibility. A lignin-based byproduct of the pulp industry, calcium lignosulfonate (LignoBond; LB) could be used as a feed additive to enhance the physical properties of aquafeeds. Hence, this study assessed the biological and technological effects of graded dietary inclusion of 0.0, 1.5, 3.0, and 6.0 g LB/kg feed on the performance and physiological status of Nile tilapia (Oreochromis niloticus) juveniles over a 75-day period. It is noted that dietary LB, particularly at 3.0 and 6.0 g/kg feed, improved feed processing metrics, notably pellet durability and water stability—critical attributes in minimizing nutrient leaching and environmental discharge. The dietary LB markedly enhanced final body weight, specific growth rate, and feed intake with the increase in LB levels; meanwhile, feed conversion ratios (1.51–1.45) were insignificantly (P > 0.05) decreased. Fish growth improvements were linked to elevated intestinal alpha-amylase and trypsin activities and pronounced stimulation of immune and antioxidant responses, including increased total protein, albumin, globulin, lysozyme activity, immunoglobulin M, complement proteins (C3, C4), superoxide dismutase, and catalase values, especially at 3.0 and 6.0 g/kg feed without significant (P > 0.05) differences between them. Concurrent reductions in plasma ALT, AST, uric acid, and creatinine were recorded in LB-fed fish with no significant (P > 0.05) differences among them; this underscored improved hepatic and renal integrity. These findings position LignoBond (3.0 g/kg feed) as an optimum biofunctional feed additive that improved feed quality along with marked enhancements in growth and the immune and antioxidative functions.

Biofloc technology (BFT) has yielded higher survival rates in the larviculture of B. amazonicus and the supply of live food during its larval stage may be an alternative for optimizing the species productivity and availability. This work aimed to compare two types of live food, Artemia salina and Moina micrura, in the larviculture of B. amazonicus in clearwater (CW – without BFT) and in BFT systems during the five days. Four hundred larvae (24 h after hatching) were distributed in four treatments: T1 (CW + M. micrura), T2 (CW + A. salina), T3 (BFT + M. micrura) and T4 (BFT + A. salina). Live food was offered once a day in increasing proportions. There was an effect of the BFT and CW systems on water quality (p < 0.05) and the type of live food influenced the total ammonia and salinity (p < 0.05). The survival of the larvae was higher in the BFT system (T3—64 ± 10.6% and T4—74.7 ± 16.2%) compared to the CW system (T3—18.7 ± 15.1% and T4—44.0 ± 20). Final weight and length, weight gain and length were higher in larvae from the BFT system, being higher in those fed with A. salina (p < 0.05). Thus, the results suggest the benefits of the BFT system in the larviculture of B. amazonicus, with A. salina being recommended for use in the first five days of life.

Jellyfish blooms pose a significant economic threat to the global aquaculture industry, causing mass mortality events in farmed fish. Automated detection systems are needed for early warning, but existing computer vision models have not been tested in the challenging visual conditions of aquaculture pens. We evaluated domain adaptation approaches and jellyfish object detection models trained specifically for aquaculture environments, comparing eight architectures including convolutional (YOLOv11) and transformer-based (RT-DETR, DINO) models. Our novel dataset comprised 31,875 jellyfish annotations across 2558 images extracted from 118 unique videos recorded in salmon farms in Tasmania, Australia, capturing jellyfish and gelatinous zooplankton under challenging conditions of high turbidity, complex backgrounds, and low visibility. To evaluate domain adaptation strategies, we combined publicly available datasets with two newly collected non-aquaculture datasets, creating a diverse corpus of 17,622 images with 32,025 annotations. Unlike previous studies, we implemented a strict evaluation protocol accounting for spatial–temporal correlations of images extracted from the same video sequence. Detection transformers consistently outperformed fully convolutional architectures. The DINO architecture with a transformer backbone achieved 56.5% mAP₅₀ when pre-trained on the combined non-aquaculture data and fine-tuned on aquaculture data—a 4.6 percentage point improvement over training on aquaculture data alone—with strongest improvements in detecting challenging categories such as ctenophores (AP₅₀ improved from 36.9% to 51.3%). This work provides the first jellyfish detection system trained and evaluated for aquaculture environments and demonstrates that transformer-based architectures with large-scale pre-training on out-of-domain data offer the most effective approach for developing jellyfish early warning systems in fish farms.