Aquaculture, Fish and Fisheries最新文献

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.

Understanding the life history traits of ecologically and economically important fish species is critical for effective management. This study provides the first detailed analysis of age, growth, diet and reproductive characteristics of African pompano (Alectis ciliaris) from the southeastern United States, expanding upon prior work from the Western Arabian Gulf. A total of 54 specimens were collected off the coasts of Georgia and South Carolina when they were available during the 2024 fishing season (May–October). Age was determined via otolith sectioning, and growth was modelled using the von Bertalanffy growth function (L∞ = 96.61 cm, K = 0.689, t0 = 0.01). Diet composition was assessed using stomach content analysis, and reproductive status was evaluated through gonadosomatic index (GSI) calculations. Results indicate that A. ciliaris in this region exhibit rapid growth and early maturity, with all specimens sexually mature and the oldest fish aged at nine years. Growth comparisons suggest regional differences, with fish from the southeastern U.S. potentially growing faster than those from the Arabian Gulf. Diet analysis revealed a strong preference for cephalopods, particularly squid, which comprised over 80% of prey items. Seasonal GSI patterns suggest peak reproductive activity occurs between June and August. These findings support the hypothesis that A. ciliaris in the southeastern U.S. are migratory, arriving from Florida waters to spawn and feed during summer months. This research contributes essential data toward the life history understanding of A. ciliaris and provides valuable insights for future fisheries management and conservation efforts for this largely unmanaged species.

Essential oils are composed of secondary metabolites derived from medicinal plants and have bioactive properties, such as antiparasitic activity. This study investigated the in vitro anti-dactylogyridean efficacy of the Zingiber officinale, Curcuma longa and Cymbopogon nardus essential oils, as well as the acute toxicity for Colossoma macropomum (tambaqui). The majority chemical components of the essential oils of Z. officinale (α-zingiberene, β-sesquiphellandrene, limonene and geranial), C. longa (ar-turmerone, α-turmerone, α-phellandrene, curlone and 1,8-cineole) and C. nardus (geraniol, geranial and neral) were analysed. All the essential oils exhibited dose-dependent efficacy against dactylogyrideans Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri, and the mean effective concentration (EC₅₀) was 16.6 mg L⁻¹ (3 h and 30 min) for Z. officinale essential oil, 30.9 mg L⁻¹ (2 h and 15 min) for C. longa essential oil and 13.7 mg L⁻¹ (30 min) for C. nardus essential oil. Effects of these oils on the ultrastructure of Anacanthorus dactylogyrideans exposed to the essential oils were also evaluated using scanning electron microscopy. This study shows for the first time the potential use of the Z. officinale, C. longa and C. nardus essential oils in controlling dactylogyridean parasites.

Mandarin fish (Siniperca chuatsi) is a high-value economic freshwater fish in China; however, the frequent occurrence of diseases threatens its production. To this end, we explored the impact of a nematode parasite newly found in the abdomen of mandarin fish collected from Pudong, Shanghai, China. This study was focused on two dimensions: (1) to use molecular biology methods to identify the taxonomic position of the nematode while also observing its morphological characteristics and (2) to assess the impact of nematode parasitism on the immune system of mandarin fish. This nematode exhibits a pink body colour and primarily resides in the swim bladder (an average 8–10 nematodes per fish). Additionally, 1–3 nematodes were observed in the abdomen, liver and peritoneum, while none were detected in the digestive tract. Initial molecular identification using universal nematode primers successfully amplified a specific band (378 bp), and BLASTn analysis revealed that the sequence showed a high similarity (99.20%) to Eustrongylides ignotus (OQ885489.1) and Eustrongylides sp. (MN066569.1, PP236907.1). The nematode was categorized under the genus Eustrongylides. In the second-round identification, specific ITS primers for Eustrongylides produced an amplification of 845 bp, which matched (100%) the sequence of MK340917.1 (E. ignotus). Therefore, we identified the nematode as E. ignotus. The trunk of the nematode is uniform in thickness, while the head and tail taper gradually. The head features several spiny papillae and papillary structures. The nematodes caused cellular vacuolation, nuclear displacement and inflammatory responses in the liver. The expressions of IL-1β, IL-8, TNF-α and NF-ĸB were up-regulated in the liver of infected fish, with the NF-ĸB displaying the most significant increase (484.37-fold). Only TNF-α was detected as significantly up-regulated in the swim bladder. This study provided essential data for molecular identification and diagnosis of nematode infections and offers initial insights into the immune response of mandarin fish.