Wild Fish Research Articles

Widespread phthalate esters and monoesters in the aquatic environment: Distribution, bioconcentration, and ecological risks

Field research on phthalate monoesters (MPEs) and their relationships with phthalate esters (PAEs) is limited, especially in wild fishes. Here, PAEs and MPEs were measured in surface water, sediment, and wild fish collected from a representative river basin with high economic development. Several metabolites of emerging plasticizers, such as mono(3,5,5-trimethyl-1-hexyl) phthalate and mono(6-oxo-2-propylheptyl) phthalate, have already existed in fish with high detection frequencies (95 % and 100 %). Monobutyl phthalate and mono(2-ethylhexyl) phthalate were the predominant MPEs in fish and natural environment (surface water and sediment), while bis(2-ethylhexyl) phthalate was the most abundant PAEs in all matrices. The total concentrations (median) of 9 PAEs and 16 MPEs were 5980 and 266 ng/L in water, 231 and 10.6 ng/g (dw) in sediment, and 209 and 32.5 ng/g (ww) in fish, respectively. The occurrence of MPEs was highly related to their parent PAEs, with similar spatial distribution characteristics in the aquatic environments. Moreover, municipal wastewater discharge was recognized as the main source of MPEs in the research area. Fish species can accumulate targeted chemicals, and it seems more MPEs were from the PAE degradation in fish other than the direct uptake of MPEs in water. Parent PAEs showed higher ecological risk than their corresponding metabolites.

Low Carbon Development Strategy in the Rambat Menduyung Mangrove Forest Area of West Bangka

Indonesia is committed to reducing carbon emissions through low-carbon development. Mangrove ecosystems have a high carbon storage value that can support this development. There is a problem of high mangrove degradation caused by economic activities. One of the sectors causing mangrove degradation is the mining sector in the province of Kepulauan Bangka Belitung. Low-carbon development strategies in mangrove areas are needed to support the increase of sustainable economic activities such as capture fisheries, aquaculture, and mangrove conservation. The objective of this research is to calculate the potential value of sustainable economic activities and develop a low-carbon development strategy in the Rambat Menduyung Mangrove Area. The methods used in this research are economic benefit analysis, benefit transfer analysis of carbon emission factors, and strategy analysis using interpretative structural modeling with Exsimpro software. The results of research suggest that potential economic activities that support low carbon development in mangrove areas, namely mangrove conservation, capture of marine biota, and blood clam production, produce economic benefits of IDR105,723,552,069/year. Prioritizing low-carbon development strategies by improving protection and law enforcement policies and increasing institutional capacity and community participation supported by adequate infrastructure from stakeholders, namely DKP West Bangka, KPHP Rambat Menduyung, and Belo Laut Village Government.

Low Carbon Development Strategy in the Rambat Menduyung Mangrove Forest Area of West Bangka

Indonesia is committed to reducing carbon emissions through low-carbon development. Mangrove ecosystems have a high carbon storage value that can support this development. There is a problem of high mangrove degradation caused by economic activities. One of the sectors causing mangrove degradation is the mining sector in the province of Kepulauan Bangka Belitung. Low-carbon development strategies in mangrove areas are needed to support the increase of sustainable economic activities such as capture fisheries, aquaculture, and mangrove conservation. The objective of this research is to calculate the potential value of sustainable economic activities and develop a low-carbon development strategy in the Rambat Menduyung Mangrove Area. The methods used in this research are economic benefit analysis, benefit transfer analysis of carbon emission factors, and strategy analysis using interpretative structural modeling with Exsimpro software. The results of research suggest that potential economic activities that support low carbon development in mangrove areas, namely mangrove conservation, capture of marine biota, and blood clam production, produce economic benefits of IDR105,723,552,069/year. Prioritizing low-carbon development strategies by improving protection and law enforcement policies and increasing institutional capacity and community participation supported by adequate infrastructure from stakeholders, namely DKP West Bangka, KPHP Rambat Menduyung, and Belo Laut Village Government.

Unraveling Greek Inland Competitive Fishing: Historical Insights, Angler Profiles, and Motivations through Limited Data Integration in Recreational Fishing Research

This study delves into the realm of competitive sport fishing in Greece’s inland waters, where recent years have witnessed a notable surge in such activities. Despite the absence of official records, insights into the sport’s trend and the motivations and socio-demographic characteristics of anglers participating in fishing competitions were gleaned from digital data sourced from online platforms and interviews with anglers. Our findings illuminate the growing popularity of sport fishing in Greece, evident in the increasing number of fishing competitions and the burgeoning angling community. Predominantly male, anglers exhibit a strong dedication to catch-and-release practices, citing relaxation and socialization as primary motivations, with competitive aspirations also shaping their involvement. Moreover, the study highlights legislative gaps in inland water fisheries regulations, underscoring the need for updates to ensure sustainable management and to mitigate illegal activities. Additionally, there exists an opportunity to bolster anglers’ ecological awareness through targeted education initiatives. Ultimately, addressing these conclusions holds the potential to foster responsible fishing practices and contribute to the long-term sustainability of inland water fisheries.

Evaluating the influence of democracy, financial development, and fishery product consumption on fishing grounds: A case study for Malaysia

Enhancing environmental sustainability in all dimensions, including marine life, is an important task for all stakeholders. The Sustainable Development Goal-14 aims to protect marine life and reduce ecological pollution in marine ecosystems. In this regard, this study aims to examine the influence fishery product consumption, economic growth, democracy, and financial development on fishing footprint in Malaysia. For this purpose, three different models are employed under the Environmental Kuznets Curve (EKC) framework from 1961 to 2018. The empirical results can be summarized as follows: (i) The EKC is not valid for Malaysia’s fishing footprint (ii) Fishery product consumption and economic growth increase the fishing footprint, while population and financial development reduces pollution in fishing grounds (iv) Democracy has no impact on fishing footprint. Based on the research findings, the Malaysian government is recommended to promote green economic regulations for fisheries, environmental financing, and clean fishery products in order to mitigate the fishing footprint.

Assessing transgenerational gene editing capacity for enhancing aquaculture productivity in decapod crustaceans

AbstractIn the wake of global population increases and stagnating capture fishery production, there exists a requirement for novel biotechnologies to increase aquaculture productivity to offset demand. Through recognition of limitations imposed by aquaculture—increased incidence of disease, stress, cannibalism, and mortality in captivity—researchers continue to investigate RNA interference (RNAi) and clustered regularly interspaced short palindromic repeat (CRISPR) technologies for their potential to alleviate these at a genetic level. In decapods, with the exception of generating desirable all‐male monosex populations in Macrobrachium rosenbergii, RNAi and CRISPR technologies have yet to provide a significant commercial use case. This literature review provides a comprehensive examination of RNAi and CRISPR in decapods, along with popular delivery methods (injection/microinjection; electroporation; receptor‐mediated ovary transduction of cargo [ReMOT]; and nanoparticles). It identifies a number of limitations including scalability bottlenecks imposed by RNAi delivery methods, and deferred gene editing progress as a result of CRISPR's infancy. Finally, it recognises gene editing induced gene silencing (GEiGS®) as a novel method for silencing gene expression, and suggests an interim examination of transgenerational gene silencing (TGS) (‘parental RNAi’) in decapods to enhance aquaculture productivity.

The use of corrective action frameworks in international fisheries management

Compliance frameworks are important to promoting sustainable management of shared fisheries resources through the robust and transparent assessment of the implementation of conservation measures by States that are party to international agreements. This paper provides a review of existing compliance frameworks, with a special focus on corrective actions to respond to non-compliance in regional fisheries management organisations or arrangements, as well as a selection of multilateral environmental organisations. The analysis of the surveyed schemes of corrective actions identifies common themes and practices, which can provide a foundation on which to support the development of, or refinement of existing, schemes of corrective actions by other international organisations or arrangements.

Flexibility through bundles of capital: The capabilities of Indonesian small-scale handline tuna fishers under voluntary sustainability certification

As key tuna producers and exporters globally, developing countries are exposed to voluntary sustainability certification to respond to market and consumer demands. Only recently, small-scale fisheries have received attention in this respect. Despite small volumes traded, fishing activities are essential for maintaining the livelihoods of small-scale fishers. Their environmental footprint is lower than large-scale fisheries, yet lack of capital, capabilities, and conflicting interests along the value chain have hindered their participation in certification schemes. This study employs Sen’s capability approach to understand the extent to which a voluntary standard develops the capabilities of small-scale tuna fishers. We use a case study of the Fair Trade USA Capture Fisheries Standard (CFS) in the province of Maluku, Indonesia, established in collaboration with an Indonesian non-governmental organization, Yayasan Masyarakat dan Perikanan Indonesia. We show that fishers use a bundle of different kinds of capitals to develop their capabilities for compliance with the certification standard. This bundle of capitals consists of a combination of prescribed capitals (the capitals necessary to comply with the certification standard) and alternative capitals that fishers use to develop their abilities for their compliance. Instead of using human capital as emphasized by the certification standard, in this study, we found that fishers use social capital as their main capital to comply with the standard, which makes it the primary source for improving their capabilities. In conclusion, we found support for the need to strengthen flexibility in the implementation of sustainability standards to increase their effectiveness as a sustainability governance mechanism.

Chemical Composition of Two Grey Mullet Species (Chelon auratus, Mugil cephalus): A Comparative Study on Wild and Aquaculture-Adapted Species

This study assessed the chemical composition of wild and culture-adapted golden grey mullet (Chelon auratus) and flathead grey mullet (Mugil cephalus). Wild samples were collected seasonally from Trabzon shores and compared to those adapted to aquaculture conditions for one year. Both species had high levels of glutamate, aspartate, alanine, leucine, and isoleucine. Mugil cephalus was a high protein source for adults, with a digestible indispensable amino acid score (DIAAS) score above 100 in both wild and culture forms. However, a DIAAS score exceeding 100 was only detected in wild Chelon auratus in the winter and spring. Both species had high levels of EPA and DHA, with Mugil cephalus having the highest lipid quality. Despite seasonal variations, cultured fish maintained a good nutritional profile similar to wild fish, especially in the autumn and summer.

Farmers’ Perceived Impact of High-Dikes on Rice and Wild Fish Yields, Water Quality, and Use of Fertilizers in the Mekong Delta, Vietnam

Farmers’ Perceived Impact of High-Dikes on Rice and Wild Fish Yields, Water Quality, and Use of Fertilizers in the Mekong Delta, Vietnam

The Response of the Gut Physiological Function and Microbiome of a Wild Freshwater Fish (Megalobrama terminalis) to Alterations in Reproductive Behavior.

The fish gut microbiome is well known for its role in degrading nutrients to improve the host's digestion and absorption efficiency. In this study, we focused on the core physiological adaptability during the various reproductive stages of the black Amur bream (Megalobrama terminalis) to explore the interaction mechanisms among the fish host gut mucosal structure, gut enzyme activity, and gut microbial metabolism in the course of the host's reproductive cycle. Our findings showed that M. terminalis exhibited locomotion metabolic type (aids in sporting) in the reproductive stage, and a change to visceral metabolic type (aids in digestion) during non-reproductive and post-reproductive stage phases. The impact of metabolic type selection and energy demand during various reproductive stages on fish nutrition strategy and digestive function was substantial. Our resulted showed that mitochondria in intestinal epithelial cells of reproductive M. terminalis appeared autophagy phenomenon, and the digestive enzyme activities in the intestines of reproductive M. terminalis were lower than those in the non-reproductive and post-reproductive individuals. Moreover, these differences in nutrition strategy have a prominent impact on the gut microbiome of reproductive M. terminalis, compared to non-reproductive and post-reproductive samples. Our findings showed that reproductive females had lower levels of alpha diversity compared to non-reproductive and post-reproductive females. Our results also showed a greater functional variety and an increase in functional genes related to carbohydrate, lipid, amino acid, cofactors, and vitamin metabolic pathways in the NRS and PRS group. It is noteworthy that an enrichment of genes encoding putative enzymes implicated in the metabolism of taurine and hypotaurine was observed in the RS samples. Our findings illustrated that the stability and resilience of the gut bacterial community could be shaped in the wild fish host-microbiome interactions during reproductive life history.

Single generation epigenetic change in captivity and reinforcement in subsequent generations in a delta smelt (Hypomesus transpacificus) conservation hatchery.

A refugial population of the endangered delta smelt (Hypomesus transpacificus) has been maintained at the Fish Conservation and Culture Laboratory (FCCL) at UC Davis since 2008. Despite intense genetic management, fitness differences between wild and cultured fish have been observed at the FCCL. To investigate the molecular underpinnings of hatchery domestication, we used whole-genome bisulfite sequencing to quantify epigenetic differences between wild and hatchery-origin delta smelt. Differentially methylated regions (DMRs) were identified from 104 individuals by comparing the methylation patterns in different generations of hatchery fish (G1, G2, G3) with their wild parents (G0). We discovered a total of 132 significant DMRs (p < .05) between G0 and G1, 132 significant DMRs between G0 and G2, and 201 significant DMRs between G0 and G3. Our results demonstrate substantial differences in methylation patterns emerged between the wild and hatchery-reared fish in the early generations in the hatchery, with a higher proportion of hypermethylated DMRs in hatchery-reared fish. The rearing environment was found to be a stronger predictor of individual clustering based on methylation patterns than family, sex or generation. Our study indicates a reinforcement of the epigenetic status with successive generations in the hatchery environment, as evidenced by an increase in methylation in hypermethylated DMRs and a decrease in methylation in hypomethylated DMRs over time. Lastly, our results demonstrated heterogeneity in inherited methylation pattern in families across generations. These insights highlight the long-term consequences of hatchery practices on the epigenetic landscape, potentially impacting wild fish populations.

Navigating aquaculture losses: Tackling fish‐killing phytoflagellates in a changing global landscape

AbstractAquaculture has emerged as a pivotal alternative for seafood production, addressing the challenges posed by depleting wild fish stocks. However, the industry faces substantial challenges, notably the presence of harmful algal blooms (HABs), which can cause serious economic consequences. The proliferation of major species of phytoflagellates leading to massive fish mortality is on the rise, possibly attributed to increasing global temperatures and eutrophication. This underscores the critical need for robust detection, prevention, and mitigation strategies to safeguard the aquaculture industry. This contribution offers valuable insights into comprehending and addressing the challenges posed by HABs in the fish aquaculture sector in an era of global change.

Rodenticide contamination of cormorants and mergansers feeding on wild fish

AbstractExposure of wildlife to anticoagulant rodenticides from sewer baiting and bait application is poorly understood. We analyzed residues of eight anticoagulant rodenticides in liver samples of 96 great cormorants, 29 common mergansers, various fish species, and coypu, in different German regions. Results show that hepatic residues of anticoagulant rodenticides were found in almost half of the investigated cormorants and mergansers due to the uptake of contaminated fish from effluent-receiving surface waters. By contrast, exposure of coypu to rodenticides via aquatic emissions was not observed. The maximum total hepatic anticoagulant rodenticide concentration measured in waterfowl specimens was 35 ng per g based on liver wet weight. Second-generation anticoagulant rodenticide active ingredients brodifacoum, difenacoum, and bromadiolone were detected almost exclusively, reflecting their estimated market share in Germany and their continuing release into the aquatic compartment. Overall, our findings reveal that second-generation anticoagulant rodenticides accumulating in wild fish are transferred to piscivorous predators via the aquatic food chain.

Regulatory gene network for coffee-like color morph of TYRP1 mutant of oujiang color common carp

BackgroundNeither a TYRP1-mediated highly conserved genetic network underlying skin color towards optimum defense nor the pathological tendency of its mutation is well understood. The Oujiang Color Common Carp (Cyprinus carpio var. color) as a model organism, offering valuable insights into genetics, coloration, aquaculture practices, and environmental health. Here, we performed a comparative skin transcriptome analysis on TYRP1 mutant and wild fishes by applying a conservative categorical approach considering different color phenotypes.ResultsOur results reveal that an unusual color phenotype may be sensitized with TYRP1 mutation as a result of upregulating several genes related to an anti-inflammatory autoimmune system in response to the COMT-mediated catecholamine neurotransmitters in the skin. Particularly, catecholamines-derived red/brown, red with blue colored membrane attack complex, and brown/grey colored reduced eumelanin are expected to be aggregated in the regenerated cells.ConclusionsIt is, thus, concluded that the regenerated cells with catecholamines, membrane attack complex, and eumelanin altogether may contribute to the formation of the unusual (coffee-like) color phenotype in TYRP1 mutant.

Measuring activity-rest rhythms under different acclimation periods in a marine fish using automatic deep learning-based video tracking

ABSTRACT Most organisms synchronize to an approximately 24-hour (circadian) rhythm. This study introduces a novel deep learning-powered video tracking method to assess the stability, fragmentation, robustness and synchronization of activity rhythms in Xyrichtys novacula. Experimental X. novacula were distributed into three groups and monitored for synchronization to a 14/10 hours of light/dark to assess acclimation to laboratory conditions. Group GP7 acclimated for 1 week and was tested from days 7 to 14, GP14 acclimated for 14 days and was tested from days 14 to 21 and GP21 acclimated for 21 days and was tested from days 21 to 28. Telemetry data from individuals in the wild depicted their natural behavior. Wild fish displayed a robust and minimally fragmented rhythm, entrained to the natural photoperiod. Under laboratory conditions, differences in activity levels were observed between light and dark phases. However, no differences were observed in activity rhythm metrics among laboratory groups related to acclimation period. Notably, longer acclimation (GP14 and GP21) led to a larger proportion of individuals displaying rhythm synchronization with the imposed photoperiod. Our work introduces a novel approach for monitoring biological rhythms in laboratory conditions, employing a specifically engineered video tracking system based on deep learning, adaptable for other species.

Vessel Monitoring System (VMS) Technology as a Management Strategy for Longline Tuna Capture Fisheries in Benoa

Benoa Port has fishing vessel activities that are the foundation of Bali's tuna swamp fisheries (longlines). Sustainable tuna capture fisheries will be impossible to attain if the number of infractions in the marine and fisheries sectors continues to rise. The government's efforts to reduce infractions in marine and fisheries are achieved through tightening the oversight system. The Vessel Monitoring System (VMS) surveillance system was created to reduce breaches in the marine and fishery sectors. The goal of this study is to determine the monitoring and suspected indication of violations of longlines using the VMS at the Benoa PSDKP as well as to learn about the capture fisheries management strategy using VMS data on longlines at Benoa Port using an analytic hierarchy process (AHP) approach. This study used a qualitative-quantitative descriptive technique with AHP analysis to determine the value of the management priority scale. Based on the findings of monitoring longlines with web tracks from January to December 2022, the most targeted fishing area was the Indian Ocean High Seas, and the most prominent suspected indication of violation was the inactivity of VMS when the vessel was operating. The main approach for managing capture fisheries utilizing VMS data on longlines in Benoa Port with the AHP analysis is for the government to offer subsidies for installing VMS on all fishing vessels, particularly those under 30 GT.

Domestic fish for more versatile and safer consumption EU‐fish IV

Abstract Fish is an important part of nutrition and well‐being. The challenge of Finnish wild fish is contaminants which accumulate in some species in higher concentrations, partially limit the usability of the fish in the food/feed market and weaken the assessment of the state of the marine environment. The aim of this study was to obtain data on the amounts of nutrients and contaminants in domestic fish species that are commercially important or should be increased in use according to national plans. The aim was also to produce information for updating the national fish use recommendations. The concentrations of contaminants in Finnish fish were mostly below the maximum levels set by the EU. The trend of dioxin and PCB compound concentrations in the Baltic Sea has been declining since the 1980s, and the concentrations in Baltic herring appear to have settled around or below the maximum levels in all sea areas and size classes. The PFAS concentrations in the studied fish samples were within the maximum limits, except for Baltic herring in the Archipelago Sea and the Bothnian Sea. Additionally, the PFAS concentrations in Baltic herring rose quite sharply between 2009 and 2023. During the current study, PFAS concentrations in Baltic herring from the same sea area and size classes increased significantly from autumn 2022 to spring 2023. The seasonal trend was suspected to be related to the fish's diet, but factors affecting PFAS concentrations in fish, such as the impact of seasons and fitness (function of weight and size of the fish), need further investigation, and PFAS concentrations in Baltic herring should be monitored. PBDE concentrations in Finnish fish were found to be very low, although they exceeded the environmental quality standard. Mercury concentrations in fish, except for two samples, were lower than the maximum levels set by Commission Regulation (EU) 2023/915. The proportion of methylmercury in total mercury was 56–94% in different fish species. Inorganic arsenic concentrations in all fish samples were below the detection limit of 0.01 mg/kg. The highest concentrations of omega‐3 fatty acids were measured in Baltic herring and vendace. Fish caught from marine areas had higher vitamin D concentrations than those from inland waters, and there was significant variation in concentrations within fish species. With current food consumption and concentration data, the health benefits of fish consumption outweigh the health risks associated with contaminants in fish for all age groups. The greatest health benefits are seen in those over 45 years old, where fish consumption reduces the burden of diseases such as cardiovascular diseases and breast cancer, as well as overall mortality. On a national scale, the current use of domestic and imported fish is estimated to reduce the disease burden annually by nearly 70,000 disability‐adjusted life years (DALYs). As a conclusion, the health benefits of fish consumption outweigh the harms of contaminants in all age groups. Increasing the consumption of fish in accordance with nutritional recommendations would benefit the health of the population. For children and expectant or breastfeeding mothers, a diverse fish consumption is useful. The safe use recommendations of the Finnish Food Authority help this risk group to direct their fish consumption to fishing areas and fish species with the lowest amounts of contaminants.

Improving impact assessments to reduce impacts of deep-sea fisheries on vulnerable marine ecosystems

Robust impact assessments (IAs) for deep-sea fisheries are essential for safeguarding deep-sea ecosystems against the impacts of bottom fishing. In the high seas, United Nations Resolution commitments require States (independently or through Regional Fisheries Management Organisations (RFMOs)) to conduct IAs to evaluate if fishing is putting vulnerable marine ecosystems (VMEs) at risk. To enhance the efficacy of future IAs, this study evaluated nine IAs against the criteria in the FAO International Guidelines for the Management of Deep-Sea Fisheries in the High Seas. We find that in all IAs, the information required by the FAO Guidelines is either completely lacking or only partially addressed. The main shortcoming of the IAs was inadequate description of the ecosystems potentially affected by fishing. Additional shortcomings include incomplete description of the proposed fishing activities, lack of baseline data and risk assessments, and limited consideration of the indirect impacts of fishing. This study identifies several ways to strengthen the IA process; i) making IAs publicly available; ii) improved collection of baseline data and VME identification; iii) assessment of impacts on broader range of species associated with VMEs or potentially impacted by deep-sea fishing; iv) enhanced cooperation between RFMOs and more streamlined IA processes; v) comprehensive assessment of different types of impacts from fishing and climate change, and vii) improved consideration of uncertainty. Fully compliant IAs are a minimum requirement for the effective function of RFMOs, since they are the primary tool for preventing significant adverse impacts upon vulnerable marine ecosystems and the wider deep-sea environment.

Prevalence of Gastrointestinal Parasites of African Catfish (Clarias gariepinus) from River Nasarawa, Nasarawa State, Nigeria

Fish and fish products are significant sources of nutrients for humans. Parasites of fish are of concern since they often produce a weakening of the host’s immunity thereby increasing susceptibility to secondary infections. This study was conducted with aimed to examine the prevalence of gastrointestinal parasites infecting fish. Field study was conducted during the period from September to November 2022. A total of 200 fish samples (Clarias gariepinus) were examined for the presence of gastrointestinal parasites. Result show that, total number of fishes infected 60(30.0%) out of which 26(26.26%) males and 34(33.66) female. Two helminths one each from Cestode and Nematode were isolated from the infected fishes. The Cestode and its prevalence were Diphylobothrium latum (5%) and nematode Procamallanus spp. (3.33%). The protozoa recovered included: Hexamita spp., Protoopalina spp. and Microsporidia with 60.00%, 23.33% and 18.34% respectively. The majority of the parasites were found in the intestine. Fish specimens that were lighter in weight 10 -200g had less infection (12.5%) but those found with parasites weighed between 201-400g (42%). There was no significant difference (P&gt;0.05) in the infection between male and female Clarias gariepinus and with age on the prevalence and intensity of the gastrointestinal parasite. Wild fish (Clarias gariepinus) in River Nasarawa have a high prevalence of intestinal parasites, therefore it is recommended to avoid open defecation that finally is washed down to rivers and streams hence affecting the aquatic organisms and to properly cook wild fish obtained from River Nasarawa before consumption for safety.