Aquaculture, Fish and Fisheries最新文献

This study assessed the growth performance and feed utilisation of Asian seabass (Lates calcarifer) cultured under three salinity regimes (5–6, 8–10 and 2–4 ppt) in pilot-scale earthen ponds in coastal Bangladesh. Fish were stocked at 60 per decimal and fed commercial pellets throughout the trial over 254 days, with water quality consistently monitored. Data were analysed using one-way analysis of variance (ANOVA) with post hoc Games–Howell test. Significant differences (p < 0.05) were observed among salinity treatments in final body weight (BW), weight gain (WG), length gain, specific growth rate (SGR) and daily WG. Fish at moderate salinity (5–6 ppt) showed the highest growth (final BW: 840.02 ± 1.30 g; SGR: 2.16% ± 0.01% per day). Feed utilisation metrics were also superior at 5–6 ppt, including the lowest feed conversion ratio (1.27 ± 0.002), highest feed efficiency ratio (0.79 ± 0.001) and protein efficiency ratio (1.96 ± 0.003). Survival was greatest at 5–6 ppt (85.11% ± 0.15%) than in lower and higher salinity regimes. These findings indicate that maintaining moderate salinity (≈5–6 ppt) optimises growth, feed utilisation and survival in L. calcarifer, providing practical guidance for Asian seabass aquaculture in Bangladesh.

Grouper iridovirus (GIV) is a large DNA virus belonging to the family Iridoviridae and genus Ranavirus. It consists of 139,793 base pairs (bp) and 120 open reading frames (ORFs). GIV is a key pathogen of farmed fish worldwide. The functional roles of viral genes must be determined for the early diagnosis, treatment and prevention of viral infections. This study explored the characteristics of GIV-5L during viral infection. Sequence analysis of GIV-5L was performed using the National Center for Biotechnology Information (NCBI) database, leading to preliminary speculation that GIV-5L is a viral protein unique to Ranavirus. GIV-5L recombinant protein was used to immunize mice to obtain polyclonal antibodies against GIV-5L. The expression characteristics of the GIV-5L gene were then analysed. Gene expression time was analysed using cycloheximide (CHX) and cytosine arabinoside (AraC) during the infection of grouper kidney (GK) cells with GIV. GIV-5L expression was inhibited by CHX and AraC, confirming their role as late genes. Immunofluorescence staining confirmed GIV-5L expression in the cytoplasm at 12-hours post-infection (hpi) and in the nucleus at 24 hpi. This study demonstrated the functional characteristics of the GIV-5L gene, which could provide insights into GIV assembly and facilitate GIV diagnosis.

The spatiotemporal distribution of marine organisms in Taiwan is influenced by the convergence of three major water masses and the East Asian monsoon system. However, most studies on marine fish communities have focused on larval stages due to sampling limitations. To address this gap, we applied environmental DNA (eDNA) metabarcoding to assess fish diversity across three spatial scales and four seasons and to identify environmental drivers shaping these patterns. In 2023, a year-long eDNA survey at 24 offshore sites detected 1026 marine fish taxa. The results revealed strong spatial and seasonal variation in community composition, closely tied to regional oceanography. In Eastern Taiwan, fish assemblages were mainly influenced by the Kuroshio Current, with distinct patterns in the northeast likely shaped by upwelling. In Western Taiwan, seasonal changes in northern communities reflected alternating dominance of water masses from the South China Sea and China coastal shelf, whereas southern communities remained relatively stable under the combined influence of the South China Sea Surface Current and a Kuroshio Branch. These findings advance our understanding of offshore fish biodiversity dynamics in Taiwan and highlight the role of oceanographic processes in shaping community structures, offering critical insights for long-term monitoring and marine ecosystem management.

This study evaluated the production performance and profitability of an integrated multi-trophic aquaculture (IMTA) system by incorporating Indian major carp (Labeo rohita), small indigenous fish species (SIS) (Amblypharyngodon mola), snails (Pila globosa) and the floating vegetable water spinach (Ipomoea aquatica) into traditional freshwater prawn (Macrobrachium rosenbergii) ponds. Fifteen earthen ponds of 60 m² were randomly allocated to five treatments: T₁ - prawn and rohu (finfish), T₂ - prawn, rohu and mola, T₃ - prawn, rohu, mola and snail, T₄ - prawn, rohu, mola, snail and water spinach. A control was maintained, stocked exclusively with prawns. The stocking densities of the species were 2, 0.1, 2 and 0.25 m⁻² for prawns, rohu, mola and snails, respectively. In addition, 20 water-spinach sprouts were planted in a floating bed of 0.14 m². The culture period of the experiment was 7 months. The average weight throughout the experiment, final weight, weight gain and gross production of prawns were significantly higher in T₄ compared to the control group (p < 0.05). A similar level of gross prawn production was observed in T₃, which also showed significantly higher survival and gross production of rohu compared to the other groups. In addition, the production of water-spinach and snails made a surplus profit to T₄. The gross return, net profit and benefit cost ratio was significantly higher in T₄, followed by T₃ and T₂, compared to T₁ and control. The introduction of water spinach significantly reduced the concentrations of ammonia (0.02 ± 0.01mgL⁻¹), nitrite (0.05 ± 0.03mgL⁻¹), nitrate (0.27 ± 0.01mgL⁻¹), phosphate (0.03 ± 0.00mgL⁻¹) and free CO₂ (7.52 ± 5.25) in pond water compared to other groups. This reduction is attributed to the biological purification of organic and inorganic waste, enhancing the overall utilization of the trophic layers. Therefore, the application of IMTA is crucial for sustainable prawn farming to ensure food and nutritional safety.

Climate change is altering north-temperate lake ecosystems through warming and increased aquatic macrophyte production. These changes have the potential to cause ecosystem shifts that challenge status quo fisheries management and require the adoption of new strategies to resist, accept, or direct such shifts. Warming waters and increases in aquatic macrophyte production may benefit native warmwater fish species (e.g., bluegill Lepomis macrochirus, largemouth bass Micropterus nigricans), while negatively affecting native cool- and coldwater species (e.g., yellow perch Perca flavscens, walleye Sander vitreus) in north-temperate lakes. Our objective was to test for relationships between largemouth bass electrofishing relative abundance (catch-per-unit-effort, CPUE) and population size structure (proportional size distribution, PSD) and aquatic macrophyte coverage for 186 lake-years during 2005–2018 (108 unique lakes) across northern Wisconsin lakes. Largemouth bass CPUE and PSD-Memorable were significantly, positively related to aquatic macrophyte coverage. We found no relationship between largemouth bass PSD-Stock, PSD-Quality, or PSD-Preferred and aquatic macrophyte coverage. Our findings suggest that managing aquatic macrophyte coverage may increase largemouth bass relative abundance, trophy potential, and recreational angling opportunity, especially in lakes that may be unable to continue to support cool- and coldwater fish populations. Our study provides a case for integrating the Resist-Accept-Direct (RAD) decision framework into aquatic macrophyte management.

Aquaculture sector is a key contributor to global food and nutritional security, yet its rapid intensification has heightened concerns about the emergence and spread of zoonotic fish pathogens that threaten human, animal and environmental health. This scoping review provides a comprehensive synthesis of peer-reviewed literature from 1980 to 2025 on the occurrence, prevalence and control barriers of fish-borne zoonotic pathogens associated with aquaculture systems worldwide. Data were retrieved from Scopus, Web of Science and PubMed, focusing on bacterial, parasitic, fungal and viral agents with confirmed or potential zoonotic importance. A total of 289 studies met the inclusion criteria. Bacterial pathogens were the most commonly reported group, with Streptococcus iniae, Aeromonas hydrophila, Vibrio spp., Mycobacterium marinum and Edwardsiella tarda making up more than 70% of fish-borne zoonotic cases. Parasitic infections caused by Clonorchis sinensis, Opisthorchis viverrini and Gnathostoma spinigerum remain endemic in several aquaculture-intensive regions of Southeast Asia. Although less common, fungal pathogens, like Saprolegnia parasitica and Fusarium solani, pose opportunistic zoonotic threats, especially when infected fish is consumed raw or undercooked. Viral zoonotic infections linked to aquaculture remain exceedingly rare, with no confirmed human cases to date. The highest prevalence of fish-borne zoonosis sporadic outbreaks was reported in Southeast Asia, Latin America and North Africa, regions characterised by intensive aquaculture activities and limited biosecurity infrastructure. The review identifies critical gaps in epidemiological surveillance, diagnostic capacity and integrated fish-borne zoonotic risk assessment, especially in developing nations. Strengthening biosecurity, vaccination, water quality management and public health collaboration are key to mitigating these risks. Embedding aquaculture health management within a global One Health policy framework is essential to reduce fish-borne-related zoonotic pathogen transmission pathways while ensuring the sustainable expansion of aquaculture production.

In this viewpoint, we highlight two issues that we believe deserve more emphasize in the ongoing discussions on fish welfare. On the basis of the naturally or artificially selected proximate behavioural mechanism, an animal today may attempt to reach goals that are not necessarily equal to the functions that yielded higher fitness in the past process of evolution. These attempts lead to proximate ‘needs’ of animals. Accordingly, we can increase fish welfare by asking what goals fish are trying to reach (‘wanting’) and which results will satisfy their resulting needs (‘liking’). This can be done independently of the hard question about their subjective experiences. Because answering such questions of wanting and liking relies on highly experimental procedures, we should additionally think about approaches to assess fish welfare in practice in a way that goes beyond health aspects, too. Recently developed techniques open exciting avenues to tap into judgement biases of populations that may indicate welfare and may be applicable in large-scale fish production systems. Being aware of these two issues hopefully helps to temper the conflict between the two current extreme poles of either negating or assuming a high level of fish sentience in the discussion of fish welfare.

Non-indigenous species (NIS) have far-reaching economic, ecological and cultural impacts on native biota. Early detection of nuisance species is crucial for preventing their widespread establishment and conserving threatened ecosystems. Acanthophora spicifera is a red alga that has successfully colonized tropical and subtropical waters around the globe, out-competing native flora and fauna and is among the most common non-indigenous algae of shallow Hawaiian coral reefs. To assist early detection and eradication efforts of NIS, we developed a qPCR assay for the non-indigenous A. spicifera. Assay sensitivity and specificity were validated with species-specific primers targeting a 131 base-pair region of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene. Using environmental DNA (eDNA) collected from surface seawater samples across the Hawaiian Archipelago, we then estimated A. spicifera site occupancy across sites where its presence was visually confirmed, as well as a large number of sites where its presence is unknown. Through occupancy modelling of eDNA and opportunistic visual survey data, A. spicifera eDNA was estimated to be present at 17% of surveyed sites, including one in the remote Papahānaumokuākea National Marine Sanctuary (PNMS), a world heritage site that is home to numerous endemic species. Thorough investigation of control samples, high-throughput sequencing data and visual surveys suggest that the presence of A. spicifera eDNA within PNMS is associated with an emerging colonization front in the region. Our results indicate that the eDNA assay is sensitive to the presence of A. spicifera and is a cost-effective method for monitoring its distribution on impacted coral reefs.

The vermiculated sailfin catfish (Pterygoplichthys disjunctivus), an invasive species, has rapidly proliferated in Bangladesh's freshwater ecosystems, threatening native biodiversity. This study examined its morphometric traits, length–weight dynamics, condition factors and relative weight over a one-year period (August 2023–July 2024) in the Buriganga River to support management interventions. A total of 360 individuals were measured for 21 morphometric traits, and 3888 specimens were analysed for length–weight relationship (LWR), length–length relationship (LLR) and condition indices, including Fulton's condition factor (K_F), allometric condition factor (K_A), relative condition factor (K_R) and relative weight (W_R). Observed total length ranged from 4.5 to 46.2 cm, standard length from 3.2 to 39.5 cm, fork length from 4.1 to 43.8 cm and body weight from 1.04 to 1013 g—the highest weight recorded for this species in South Asia. The LWR showed positive allometric growth (pooled b = 3.04; range = 2.78–3.08), with strong correlations in LLRs (r² = 0.988–0.995). Condition indices varied significantly by month: K_F (0.4230–1.8224; mean ± SD = 0.8496 ± 0.1189), K_A (0.0045–0.0460; 0.0191 ± 0.0039), K_R (0.5390–2.4477; 1.0114 ± 0.1187) and W_R (53.8981–244.7696; 101.3785 ± 11.8748). One-way ANOVA followed by Tukey's HSD revealed strong seasonal effects—K_F (F = 120.76, p < 0.001) and K_A (F = 2732.50, p < 0.001) were lowest during October–January and peaked in August, while K_R and W_R also differed significantly (p < 0.001) with milder fluctuations. The highest condition levels observed in August reflect favourable feeding and growth conditions during the monsoon, whereas reduced winter values suggest environmental or physiological stress. These findings reveal the species’ high adaptability and physiological resilience, offering critical baseline data for designing seasonally targeted management strategies. August, identified as the peak condition period, may offer optimal timing for control interventions to reduce the ecological impact of this invasive species.

Efficient bait management and deployment strategies are essential for improving the sustainability of artisanal crab pot fisheries. This study investigated the effects of bait type, bait quantity and depth on the catch, size and bycatch composition of marine crabs in the crab pot fisheries in the Visayan Sea, Philippines. Field experiments utilized five bait treatments (salted fish, fresh fish, chicken intestines, crab shell and no bait), comparative tests of 40 versus 20 g bait quantities and depth sampling using 20 g salted fish baits from 1 to 21 m. Salted fish significantly increased the catch and size of Portunus pelagicus and provided an effective alternative to fresh fish in areas with limited refrigeration. Chicken intestines attracted higher bycatch. Catch and size of P. pelagicus increased with depth, while Thalamita sima tended to be smaller in deeper waters. Integrating bait optimization, pot modifications and spatial deployment based on depth can enhance species and size selectivity, reduce bycatch and limit the capture of undersized crabs, thereby supporting more sustainable and ecologically responsible artisanal crabbing operations.