Commercial Fisheries Research Articles

Evidence for resource partitioning in weakfishes from a coastal upwelling ecosystem

Resource partitioning plays an important role in supporting species coexistence. In a coastal upwelling ecosystem two weakfish species, Cynoscion guatucupa and C. jamaicensis co-occur and are key commercial species. The present study aimed to provide a comprehensive assessment of the feeding ecology of both species, including to; (i) quantitatively assess diet, (ii) evaluate ontogenetic and seasonal diet variations, and (iii) estimate dietary overlap in the context of competition or resource partitioning, using an integrated approach combining stomach content (SCA) and stable isotope analyses (SIA). Our results revealed that both C. guatucupa and C. jamaicensis prey mainly on pelagic fish and shrimp with ontogenetic and seasonal changes in diet detected. Weakfishes consume a large proportion of similar prey throughout the year and high isotopic niche overlap confirmed the SCA results. Despite the similar use of food resources by both species, the availability and abundance of prey promoted by seasonal upwellings and the possible spatial segregation between C. guatucupa and C. jamaicensis may promote their co-occurrence in an upwelling ecosystem. Due to their commercial value and fisheries importance in the southwestern Atlantic, these results contribute insights to support sustainable fisheries management.

Detailed Insight into Gillnet Catches: Fish Directivity and Micro Distribution

Gillnets are widely used in research and commercial fishery activities. As passive gear, gillnets can be selective and dependent on the diel migration of fish. In areas with limited littoral extent, inshore–offshore migration may cause bias in the gillnet catch. Our hypothesis was that some factors, such as gillnet saturation, fish depletion, or chemical cues, could be the cause of the bias. We used a total of 66 CEN gillnets deployed at Římov Reservoir parallel to the shore at different positions of littoral-pelagic gradient. Individual fish direction was recorded from inshore, offshore, or unknown direction (i.e., entangled fish). A total of 5791 fishes from nine different species were caught. For most fish, it was possible to determine their directivity, and most fish were captured in littoral or first pelagic gillnets. Shallower and deeper benthic gillnets differed in their bleak (Alburnus alburnus) catch. No significant differences were found between fish directions. At the species level, only asp (Leuciscus aspius) and ruffe (Gymnocephalus cernua) showed differences between the captured directions in one case. The results support the assumption that gillnet capture is a random process that to a great extent is connected to random local movements. This is good news for fish monitoring projects. Sampling catch is likely to reflect true changes in the fish community, and not the effects of the deployment of the sampling gear. The experiment also showed that fish directivity statistics can be used for investigation of fish behavior and gear performance.

The impact of plant cryoextract on productivity and factors of innate immunity of pond fish against the background of stress in the experiment

The search for effective and environmentally friendly means to increase the productivity and natural resistance of animals, especially in aquaculture, remains an urgent socio-economic task. This article presents the results of the study of the effect of the cryobiological supplement ‘Immunolife-Fish’, based on medicinal plants, on the weight gain of juvenile common carp (Cyprinus carpio) and indicators of innate immunity of two-year-old common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix) under the influence of thermal stress factor in aquarium conditions. It was found that the weight gain of juvenile carp treated with the cryobiological supplement ‘Immunolife-Fish’ was higher than that of the control group at all stages of the study. The increase was most pronounced during the first 42 days of feeding. A significant increase in the number of leukocytes was found in the blood of fish (common carp and silver carp) exposed to a heat stressor compared to control values. In fish that received a supplement of the herbal preparation during stress, this indicator only tended to increase. The effect of the stressor in fish of both species is manifested by a significant increase in the leukocyte content, a decrease in the indicators characterizing the functional state of cellular immunity — phagocytic activity and number of phagocytes, as well as a tendency to decrease the phagocytic index of neutrophils in the blood. The use of the cryobiological supplement ‘Immunolife-Fish’ in fish exposed to stress not only prevented the decrease in the phagocytic activity of neutrophils but also contributed to a slight increase in their activity in comparison with the control. A significant decrease in the activity of lysozyme and the level of circulating immune complexes, as well as an increase in the content of seromucoids, was found in the blood serum of common and silver carp under the influence of the stress factor. The use of the drug against the background of stress leveled the negative changes in the above indicators characterizing the state of the humoral link of innate immunity. In addition, a mild immune stimulating effect of the cryobiological supplement on fish of both species, which were kept in optimal conditions, was noted. The research is aimed at the development and testing of organic, environmentally friendly anti-stress and immunostimulant agents in commercial fish farming

Whether the summer fishing moratorium can improve the status of fisheries resources in the yellow sea and Bohai Sea

The China government has introduced many strategies in fisheries management of the Yellow Sea and the Bohai Sea, the most stringent of which is the summer fishing moratorium. Whether the summer fishing moratorium can restore fishery resources has always been a concern. In this study, we selected eight representative commercial fish species the Yellow Sea and Bohai Sea, including Pampus argenteus, Trichiurus lepturus, Scomberomorus niphonius, Ilisha elongata, Thamnaconus modestus, Scomber japonicus, Engraulis japonicus and Larimichthys polyactis, and used the JABBA method to study their historical exploited dynamics and current stock status. We evaluated the effectiveness of the summer fishing moratorium based on the increments of biomass and catch after its implementation and adjustments. P. argenteus and S. niphonius stocks were in the healthy status in 2022, the other six fisheries stocks were overexploited. The summer fishing moratorium had a strong conservation effect, especially after the first implementation in 1995, with the biomass of six fish species increased and the catch of seven species increased, and the total average biomass and catch increments were 21.22 % and 89.72 %. This positive effect was also reflected after the first adjustment in 2003. Although the moratorium duration was continuously extended after the second and third adjustment, the conservation effect was offset by the flooding of fishing efforts immediately after the moratorium. For the six overexploited stocks, we suggest that the allowable catch of E. japonicus, T. lepturus, L. polyactis, S. japonicus, I. elongata and T. modestus is at most 527.91 kt, 147.51 kt, 93.43 kt, 81.51 kt, 1.25 kt and 4.95 kt in the Yellow Sea and Bohai Sea, respectively.

Diving into the fish pathology of an important commercial fish species: the case of the European hake (Merluccius merluccius Linnaeus, 1758) in the northwest Mediterranean Sea

Diving into the fish pathology of an important commercial fish species: the case of the European hake (<i>Merluccius merluccius</i> Linnaeus, 1758) in the northwest Mediterranean Sea

The state of Louisiana’s freshwater commercial fishery: a study of fishermen’s attitudes towards fishing and their future

As an important contributor to Louisiana’s economy, the commercial freshwater fisheries have been the subject of growing attention in recent years by resource managers as the industry appears to be on the brink of collapse. Fewer participants are entering the field, fish buyers and processors are closing, and market prices remain stagnant. To better understand this industry, we conducted a study to characterize the commercial freshwater fisheries in Louisiana including the fishermen, the fishing operations, the effort across the state, local knowledge on management issue and barriers and opportunities for the future of the industry. We completed structured interviews at fish houses across Louisiana. The average full-time fisherman was 56 years old with about 34 years of commercial fishing experience, and catfish (Ictaluridae spp.) and buffalo (Ictobius spp.) appear to be the most sought-after finfish; however, this slightly differs by region. Overall, this study provides in-depth insight into the trends, problems, and successes of Louisiana’s freshwater commercial fisheries. This information will allow managers and other groups like cooperative extension to identify and design opportunities for the industry and utilize their information in management across the state.

Assessing the value of harmful algal bloom forecasts in the Pacific Northwest

Abstract Over the past three decades, fisheries and livelihoods on the coasts of Washington and Oregon have been severely impacted by the presence of harmful algal blooms (HABs) that produce domoic acid, a neurotoxin that accumulates in shellfish and endangers public health. Among others, recreational razor clams and commercial Dungeness crab fisheries along the Pacific Northwest (PNW) have been negatively affected, jeopardizing the economies of coastal communities that depend on tourist revenues and income generated through visits of harvesters in the region. The PNW HAB Bulletin, launched in 2008, publishes forecasts on incoming HAB events, which has enabled managers to increase toxin monitoring in high-risk locations and proceed with selected harvesting at safe beaches and delays or closures of fishing seasons, as required. In light of the value of the HAB Bulletin to local managers and communities and the occasional challenges of securing sufficient resources to ensure its continuation, this study attempts to assess the value of information (VOI) for the predictions provided by the Bulletin. Results of the study show that ongoing financial support of the Bulletin is economically justifiable. The value of HAB forecast is positively related to three primary factors: the frequency of HAB events, the precision of forecast, and the number of social and economic sectors benefiting from the forecast. The expected increase in HAB frequency and intensity due to climate change, coupled with advancements in forecasting accuracy through technological development, is anticipated to enhance the value of the forecast program.

Liquid-liquid phase separation is essential for reovirus viroplasm formation and immune evasion.

Grass carp reovirus (GCRV) poses a significant threat to the aquaculture industry, particularly in China, where grass carp is a vital commercial fish species. However, detailed information regarding how GCRV viroplasms form and their specific roles in GCRV infection remains largely unknown. We discovered that GCRV viroplasms exhibit liquid-like properties and are formed through a physico-chemical biological phenomenon known as liquid-liquid phase separation (LLPS), primarily driven by the nonstructural protein NS80. Furthermore, we confirmed that the liquid-like properties of viroplasms are essential for virus replication, assembly, and immune evasion. Our study not only contributes to a deeper understanding of GCRV infection but also sheds light on broader aspects of viroplasm biology. Given that viroplasms are a universal feature of reovirus infection, inhibiting LLPS and then blocking viroplasms formation may serve as a potential pan-reovirus inhibition strategy.

Commercial fishing vessels as marine-based sources of plastic pollution: The Namibian perspective

Plastic pollution in the marine ecosystem and their sources have been widely investigated, however some parts of the world remain under studied. Herein, we report on plastic pollution in the Namibian marine ecosystem, based on data collected by fisheries observers between 2003 and 2020 during commercial fishing activities. A total of 79 plastic pollution incidents were reported between 2003 and 2020, which consisted of unspecified non-biodegradable objects (55.7%), unspecified plastic items (25.3%), fishing gear (8.9%), plastic bottles (5.0%), plastic gloves (1.3%) and single-use plastic bags (3.8%). We found no significant Pearson correlation between the number of disposal incidents and the fisheries observer coverage (r = 0.3254, df = 14, p = 0.2187). The spatial analysis in the disposal of non-biodegradable objects show a fair distribution along the Namibian coast with more concentrations around latitude 18⁰S, 22⁰S, and 26⁰S. We conclude that fishing vessels are important marine-based sources of plastic pollution, highlighting a continuous need to raise awareness over the fishing industry, in particular seafarers, on plastic use and management. The study expands the plastic pollution knowledge by quantifying incidents of plastic pollution, plastic litter composition, and identifying spatial distribution in the Namibian waters, thus, to the best of our knowledge, represents a baseline for studies on marine plastic pollution in this oceanic region. Identifying sources of marine plastic litter and providing a spatial picture is a step closer to develop and implement specific regulatory tools to combat marine pollution.

Unintended consequences of health and safety interventions in fisheries

AbstractFishing communities globally continue to face poor health and safety outcomes, driving the expansion of fisheries occupational health and safety (OHS) interventions. However, narrowly focused OHS interventions that neglect the social and structural determinants of health may have unintended consequences. We illustrate this problem through a case study from the UK where a recent OHS intervention, the introduction of compulsory medical certificates to all commercial fishers, led to unforeseen negative impacts. Through analysis of data from interviews, focus groups and a participatory workshop in Cornwall, UK, we highlight three key findings. First, while seeking to improve safety at sea, the regulatory change actually had negative consequences for fishers' health, their access to healthcare and potentially even their safety. Second, a mismatch between the requirements of the regulation and fishers' lived experience undermined the efforts of health promotion and outreach activities. Third, a failure to account for the implications for different sectors of the fleet has contributed to mistrust that may have ramifications for future fisheries governance activity. Our research brings to the fore important implications for the design of OHS regimes in fisheries. These include the broadening of OHS approaches to consider fishers' wider health and well‐being; engagement of fishers in the development and implementation of OHS interventions to account for their lived experiences of health and safety at sea and better integrate their knowledge; support for bottom‐up fisher‐led initiatives aimed at managing health and safety at sea; and improved coordination between agencies responsible for different areas of fisheries governance.

Sustainable valorisation of freshwater fish by‐products to gelatin and fish oil by hydrothermal extraction

SummaryThis study explores the potential of hydrothermal extraction as an innovative valorisation method for the simultaneous production of gelatin and fish oil from fish byproducts. It offers an environmentally friendly alternative to conventional solvent‐based techniques by minimising the use of chemical solvents and water. We researched various major commercial freshwater fish species: striped catfish, catfish, and tilapia, and achieved a gelatin product that reflects commercial standards in chemical structure, gel strength, and pH level. The striped catfish gelatin showed the highest gel strength and viscosity (66.01 ± 0.83 g bloom and 15.3 ± 0.1 cP), but was produced at a lower yield than the catfish gelatin. On the other hand, striped catfish produced the highest yield of fish oil (13.56 ± 0.21%) and has the highest omega 3 content (3.72 ± 0.02%) than other fish oil. This innovative study demonstrates the potential of hydrothermal extraction as a sustainable method for producing gelatin and fish oil, offering eco‐friendly and nutritional benefits across a range of applications.

Assessment of microplastic pollution in eleven commercial fish species in the Gulf of İzmir (Aegean Sea, eastern Mediterranean)

With global plastic production reaching 400 million tons in 2022, concerns about plastic pollution in the seas are increasing day by day. Therefore we focused on the abundance, characteristics, and chemical composition of potential anthropogenic origin MPs within the gastrointestinal tracts (GITs) of 11 commercial fish species in the Gulf of İzmir, an area heavily impacted by human activities. Within the scope of the study, 152 fish were sampled, and microplastics were found in 64 fish. In total, 77 MPs were identified based on ATR-FTIR analysis. Significant differences were found between species regarding MP abundance. Among the species, Scomber scombrus showed the highest MP ingestion. The MP abundance in the GIT of fish decreases from surface to deeper waters. There were also significant differences (p < 0.05) in MP abundance between pelagic and demersal fish species. Results showed that 50.6 % of MPs were fragments, and 49.4 % were fibers. The most common color was black. Seven polymer types were identified, and PE was the most common. The size of the identified MPs ranged from 101 to 4901 μm, and the average value was 715.83 ± 860.66 μm. This study sheds light on the MP contamination within commercial fish species in the Gulf of İzmir and emphasizes the urgent need for enhanced marine ecosystem conservation strategies. Our findings can serve as a basis for future studies by providing essential baseline data for implementing necessary policies and regulations.

Impacts of commercial and subsistence fishing on marine and cultural ecosystem services important to the wellbeing of an Indigenous community in Hawai'i

Marine ecosystems provide essential services to coastal residents, particularly for indigenous fishing communities that have strong ties to the environment and obtain multiple benefits from their use and management of ocean spaces. However, understanding of how these are impacted by fisheries, external pressures, and ocean management, remains limited due to a focus on economic valuation and aggregated metrics. This study explores the importance of select marine ecosystem services to the wellbeing of an indigenous community in West Hawaiˈi and the observed impacts on these ecosystem services by commercial and subsistence fishing. We used a mixed-methods approach that combined a workshop with an online survey of community perceptions regarding community important marine resources and cultural values. We find that both fish and non-fish species are important to all four well-being categories, including food security, culture, mental wellbeing, and income, though the least importance was given to the economic value. This study also found that commercial fishing is perceived to have a higher negative impact on marine resources and cultural values than subsistence fishing, but a generally lower impact on non-fish than fish species. The lack of community input into legislation development and a lack of enforcement capacity were perceived to aggravate these further, whereas the integration of place-based knowledge, values and rules of the environment was seen as beneficial to both marine and cultural ecosystem services. Overall, this study shows that non-economic and disaggregated valuation approaches are critical for revealing the variable ecosystem services that marine environments provide to local communities and the importance of more inclusive resource management approaches to manage impacts on these services.

Estimating common whelk (Buccinum undatum) abundance using baited remote underwater video (BRUV)

Abstract Baited static gear fisheries targeting benthic invertebrates have expanded at a global scale. While improvements have been made in the monitoring and management of these fisheries, reliable survey methods for stock assessments of many key species are lacking. In this study we examine the viability of a baited remote underwater video (BRUV) system for obtaining abundance indices for a data-limited stock (common whelk, Buccinum undatum), and compare this method to catch per unit effort (CPUE) from commercial fishing. BRUVs capable of collecting 15 hours of timelapse footage were deployed on pot strings in two distinct whelk fishing sites, with replication over a spring-neap tidal cycle. Three potential BRUV metrics—the maximum (MaxN) and mean (MeanN) abundance and time of first arrival (T1)—were calculated for each deployment, and significant linear relationships were identified between MaxN, MeanN, and CPUE across sites. Temporal variability in BRUV indices driven by tidal dynamics was minimal, although results suggest high current speeds may reduce abundance estimates, and a potential method for predicting density on the seabed using arrival rates is also demonstrated. BRUVs are a valuable tool in developing stock assessment surveys for static gear fisheries.

Spiny lobster recreational fisheries in Australia and New Zealand: An overview of regulations, monitoring, assessment and management

Spiny (rock) lobsters occur globally and, although harvest is dominated by commercial fisheries, it is important to account for recreational harvest in stock assessments and fisheries management. This paper provides a contemporary review of recreational fishing for five spiny lobster species in Australia and New Zealand. Each jurisdiction has established approaches for collecting data which best meet their information needs (telephone-diary or telephone-recall surveys, charter logbooks, tag reporting). Jurisdictions with specific spiny lobster licences (Western Australia, Tasmania) or mandatory reporting (charter logbooks in Western Australia, tag reporting in Victoria) use these registers as a sampling frame for annual reporting of participation, fishing effort, catch (numbers) and harvest (tonnes). All other jurisdictions use a general fishing licence or general population sampling frame for telephone-diary surveys to provide periodic reporting of catch and harvest. Annual participation in spiny lobster recreational fishing was highest in Western Australia (35,236 ± SE 626 fishers in 2022–23), followed by Tasmania (13,715 ± SE 1067 fishers in 2022–23) and Victoria (5516 fishers in 2020–21). Annual recreational harvest of all spiny lobster species, combined for the most recent data collection period in each jurisdiction, was 830 tonnes; consisting mostly of Western Rock Lobster (Panulirus cygnus) from Western Australia and Southern Rock Lobster (Jasus edwardsii) from Tasmania and New Zealand. This review illustrates the various spatial scales of monitoring, reporting and assessment in each jurisdiction. All monitoring provides information on catch and harvest, with some also reporting participation, effort, carapace length and non-catch related variables. The designs underlying these approaches vary from probability-based (opt-out) and census (mandatory), and it is important to understand the benefits and inherent biases of each. Understanding the parallels between jurisdictions offers valuable insights into how to cost-effectively monitor spiny lobster recreational fisheries and integrate this data into stock assessment and harvest strategies to support sustainable fisheries into the future.

Environmental drivers affecting the status of top commercial fish stocks in the Baltic Sea: review

IntroductionLike in many parts of the world, the Baltic Sea experiences a multitude of processes and stressors that influence fish stock dynamics. This paper compartmentalizes 250 publications that examine the cumulative effects and trade-offs of some of the most significant environmental drivers (temperature change, hypoxia, nutrient enrichment, acidification, low salinity, and food-web dynamics) on the ecology of top commercial fish species in the Baltic Sea (cod, sprat, whiting, herring, flounder, and plaice).MethodsA systematic review method was applied to ensure rigorous coverage of existing literature and to provide a comprehensive synthesis of the current knowledge on the subject.ResultsThe results illustrate the extent of scientific research applicable to commercial fisheries knowledge in the Baltic Sea and identify which pressures have the greatest negative impacts on which stocks. Additionally, the findings demonstrate how well top commercial fish species have adapted to the changing environmental conditions of the Baltic Sea. In doing so, the review illustrates the upcoming challenges and underscores which stocks are likely to dominate in the future and which will face difficulties.DiscussionBy considering ecosystem-based fisheries management, this paper emphasizes the need to account for complex ecosystem interactions beyond single-stock monitoring. With increased natural hazards, top commercial fish species have reacted differently, depending on the region and their adaptive capabilities. In most cases, Clupeidae species have adapted the best to their new surroundings, Pleuronectidae resilience is varied, while Gadidae species are finding the Baltic Sea increasingly challenging.

Spatio-temporal Dynamics of Anuran Populations in the Wetlands of Korhogo, Côte d'Ivoire

Aims: The Korhogo commune contains several natural habitats that are home to a large community of frogs. But today, these habitats are facing strong anthropic pressures. This study aims to show the effect of anthropogenic activities on wetlands and the organisms that live there. Methodology: Sampling took place from June 2023 to May 2024, and samples came from experimental fishing using deep-net dip nets with 2 mm mesh or rod and line, and from commercial fishing using various gears. Results: A total of 791 individuals were caught, for a total biomass of 48.872 Kg. These individuals were divided into 5 species, 4 genera and 4 families. Spatially, diversity was highest in the lakes (80) and lowest in the rice fields (20%). Temporally, diversity was highest in the rainy season (100%) and lowest in the dry season (40%). The species Hoplobatrachus occipitalis dominated the population with 94.66% of captures. It accounted for 25.46%, 24.27%, 22.81%, 13.93% and 13.53% respectively in lakes, rice fields, rivers, wells and shallows. The strong presence of this species in the wetlands of this commune shows that these areas are highly threatened. Conclusion: This study contributes to the knowledge of the frog population and helps to combat the degradation of wetlands in the city of Korhogo.

From land to deep sea: A continuum of cumulative human impacts on marine habitats in Atlantic Canada

AbstractEffective management and mitigation of multiple human impacts on marine ecosystems require accurate knowledge of the spatial patterns of human activities and their overlap with vulnerable habitats. Cumulative impact (CI) mapping combines spatial information and the intensity of human activities with the spatial extent of habitats and their vulnerabilities to those stressors into an intuitive relative CI score that can inform marine spatial planning processes and ecosystem‐based management. Here, we mapped potential CIs of 45 human activities from five sectors (climate change, land‐based, marine‐based, coastal, commercial fishing) on 21 habitats in Atlantic Canada's Scotian Shelf bioregion. We applied an uncertainty and sensitivity analysis to assess the robustness of results and identify hot and cold spots of CIs. Nearly the entire Scotian Shelf bioregion experiences the CIs of human activities, and high CIs were frequently associated with multiple stressors. CIs varied widely across habitats: CI scores in habitats &gt;30 m deep were dominated by climate change and commercial fishing, while nearshore habitats were influenced by a much wider range of activities across all five sectors. When standardized by area, coastal habitats had among the highest CI scores, highlighting the intensity of multiple stressors in these habitats despite their relatively small spatial extent and emphasizing the importance of a multisector approach when managing coastal ecosystems. Robust hot spots of CIs (i.e., areas with high CI scores that were insensitive to alternative modeling assumptions and simulated data quality issues) occurred mostly in coastal areas where multiple high‐intensity activities overlapped with highly vulnerable biogenic habitats. In contrast, robust cold spots of CI mostly occurred offshore. Overall, our results emphasize the need to consider CIs in management and protection and demonstrates that, in many areas, targeting only one activity will be insufficient to reduce overall human impact. The CI map will be useful to highlight areas in need of protection from multiple human impacts, provide information for ecological indicator development, and establish a baseline of the current state of human use in the bioregion.

The mitochondrial genome of the Yellowtail Snapper Ocyurus chrysurus (Bloch, 1791) (Perciformes: Lutjanidae)

ABSTRACT The yellowtail snapper Ocyurus chrysurus Bloch, 1791 (Perciformes: Lutjanidae) is targeted by recreational or commercial fisheries across much of its range in the western Atlantic Ocean, from Massachusetts, USA, to São Paulo, Brazil. Genomic resources to support conservation of this species are needed. Here, we assembled, annotated and characterised in detail the mitochondrial genome of O. chrysurus. The mitochondrial genome of O. chrysurus is 16,502 bp in length and encodes 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), and two ribosomal RNA genes (rRNA). The putative control region, 827 bp in length, is located between the tRNA P and tRNA F genes. Most genes are encoded on the positive strand, while a single PCG (nad6) and six tRNA genes (in order from 5′ to 3′: tRNA N, tRNA P, tRNA E, tRNA Q, tRNA C and tRNA Y) are encoded on the negative strand. All tRNA have a typical ‘cloverleaf’ secondary structure except tRNA S1 (Serine1) that lacks the D arm. Calculated Ka/Ks values of all PCGs were <1, suggesting that these genes are under purifying selection. A maximum likelihood (ML) phylogenetic analysis confirmed monophyly of the family Lutjanidae and indicated that the genus Lutjanus is paraphyletic given that O. chrysurus clustered together with Lutjanus peru and L. guttatus in a strongly supported clade. Data published herein will inform conservation and management strategies for this fished snapper.

Methylmercury in commercial fish species from the Erhai Lake Basin, Southwest China: concentrations, health risk assessment, and implications for future monitoring.

Erhai Lake, a highland lake situated in Southwest China, provides critical aquatic protein sources for the local community, and its preservation is vital due to the sensitivity of alpine freshwater ecosystems to disturbance. However, there is a lack of research on the contamination status of methylmercury (MeHg) in aquatic organisms of the Erhai Lake Basin. MeHg concentrations in important commercial fish species from the Erhai Lake were examined, and the potential health risks associated with human consumption were assessed. Our results showed significant inter-species differences in fish muscle MeHg: the carnivorous S. asotus exhibited the highest level (303ng/g; ww), while that of the detritivorous R. ocellatus was the lowest (3.86ng/g). Moreover, MeHg concentrations in P. fulvidraco and C. auratus collected from the Luoshi River (a major tributary of Erhai Lake) were significantly higher compared to those from the Erhai Lake, indicating possible river-based input of MeHg into the Erhai Lake. Additionally, our study revealed a significant positive correlation between the MeHg levels and the length as well as weight of the examined fish species. All the fish species analyzed in our study had MeHg concentrations within the limits of China's food safety standard. Nevertheless, a relatively low consumption quantity of 16g per day of certain species (i.e., S. asotus) may still pose potential health risks especially for children. The present study provides baseline data for MeHg monitoring and risk assessment in the Erhai Lake Basin, and warrants continued monitoring and source investigation.