Reviews in Fish Biology and Fisheries最新文献

Herbivorous fishes, and the productivity of algal turfs, are widely viewed as central to the functioning of coral reefs. This understanding is largely based on clear-water reefs. Our knowledge of herbivorous fishes and the nature of their nutritional resources on turbid reefs, by contrast, remains relatively limited. We therefore explored the nature of herbivorous fishes and the epilithic algal matrix (EAM) on turbid coral reefs across the Dampier Archipelago in northern Western Australia. We conducted comprehensive surveys of herbivorous fish abundances across natural turbidity gradients. Moreover, we quantified the trophodynamic functioning of herbivorous fishes relative to EAM structure and productivity. We revealed a clear relationship between turbidity gradients and herbivorous fish abundance, with herbivorous fishes being virtually absent from high turbidity reefs. Across the Dampier Archipelago, EAMs were typified by sediment-laden turfs with a limited propensity to deliver nutritional resources to fishes, while the productivity (i.e. the capacity for individuals to grow and produce new biomass) of herbivorous fishes was low and a fraction of that documented on clear-water reefs in the Indo-Pacific. Given the tight coupling between herbivorous fishes and their nutritional resources, these findings imply bottom-up nutrient resource limitation, which is likely due to reduced light levels and sediment-laden conditions inhibiting EAM productivity on turbid reefs. Our results suggest that EAM-based trophic pathways may be particularly unproductive on turbid reefs, with this energetic pathway playing a limited role in reef functioning compared to reefs in clear water.

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It is globally recognized that freshwater anglers can have a decisive role in promoting fish introductions. The aim of this study was to analyze freshwater anglers’ actions and perceptions regarding fish introductions, comparing two distinct situations, one with recently arrived non-natives fishes and another with older fish introductions, using the Iberian Peninsula as a case study. To achieve this goal, a bilingual survey was implemented on-line in Portugal and Spain and in person (direct inquiries) in two Iberian regions: Lower Ebro (older fish introductions) in Spain; and Lower Tagus (recent fish introductions) in Portugal. Results showed spatial differences in perceptions and actions, namely about the target species, awareness of the impact of non-native fishes, fish introductions reported and proportion of anglers that wanted new fish species. In the Ebro river there is a high percentage of foreign anglers, higher awareness of fish introduction impact and lower introduction rates reported than in the Tagus river. However, popularity of non-native species like European catfish, was higher in the Ebro. In general, although risk behaviors such as use of fish as life bait was of low prevalence for both countries (approx. 5%), it corresponds to large numbers of fish being introduced. Our conservative estimates revealed 273,600 events of bait discharge per year. Regarding the intentional introductions, we estimated a total of 140,000 intentional introduction (illegal) events per year. These findings may help to improve monitoring, awareness and fisheries management programs led by governmental agencies.

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Long-term biological time series are essential to evaluate previous responses of organisms to alterations in the environment. Biochronological methods based on archival fish otoliths allow setting such time series, but their predictive potential as proxies of past environmental conditions is still underexploited. In this study, we reconstructed growth variation in European sprat (Sprattus sprattus) in the Baltic Sea from 1956 to 2020 based on measurements of the archived otoliths. We used otolith annual increment widths as a proxy of fish somatic growth. We showed significant negative relationships between sprat growth and sprat spawning stock biomass (SSB) associated with strong intraspecific competition for limited food resources. We also identified a link between sprat growth and water salinity—indicator of the ecosystem's hydrological situation. For the first time, we estimated the SSB prior to the period of available historical data based on the otolith-derived information on the past growth variation. This estimation was based on the strong relationships between SSB and fish growth, complemented with temperature and salinity variables as predictors (R² = 0.62). A model trained on at least 40 years of data from the more recent past allows us to robustly back-estimate SSB. This study provides new multidecadal data, giving insights into environmental factors affecting the growth of Baltic sprat, and demonstrates the potential of otolith-based biochronology for the provisioning of independent indices of the historical fish stock size. The proposed methodological approach broadens the portfolio of possible applications of the biochronology time series to indicate past changes in the aquatic environment.

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Rhino rays (Order Rhinopristiformes) are one of the most threatened vertebrate groups. Despite overfishing being recognised as the greatest threat to this group, a comprehensive assessment of the fisheries and types of fishing gear that rhino rays interact with is lacking. We reviewed published and grey literature (n = 116 references) to evaluate interactions between rhino rays and fisheries, determine gear types most responsible for their capture, and species for which most interactions occur by region. Interactions (n = 420) were reported from 37 of 88 range states, for 52 of 68 known species. Combined, 59% of the literature reported interactions from trawlers and gillnets. Wedgefishes (Rhinidae) were the most reported family (29%) and bowmouth guitarfish (Rhina ancylostomus) the most reported species (9.5%). Asia accounted for half of interactions (n = 211), with 67% of the literature from unspecified gear (e.g., mixed landings), masking gear-specific interactions. Data quality was variable, with the highest resolution in countries with lower species diversity and where species are least imperiled (e.g., Australia). Discard mortality and physiological effects of capture are poorly known with data available for 25% of species (almost exclusively from Australia and the Americas). While additional data are urgently required to quantify the true extent of rhino ray catch globally, reducing fisheries mortality is a priority and key to address declining populations. Recommendations include prioritizing spatial management in critical habitats (e.g., nursery areas), expansion in the use of proven bycatch reduction devices, encouraging safe release and handling, and addressing drivers of retention and trade.

Being the world’s largest seafood producer, China’s mariculture is critical for ensuring national and global food security, yet greatly threatened by climate change. It is essential to assess the potential opportunities and challenges for Chinese mariculture in light of climate change. Although the impact of climate change on mariculture potential at a global scale has been investigated, studies at sub-national scales of China are scarce, particularly those that take into account multiple environmental stressors and species. Here, we applied a combination of physical and biological models to quantify the spatiotemporal variation in the mariculture potential of seven finfish species and seven bivalve species cultured in China under the emission scenarios SSP5-8.5 and SSP1-2.6 in the twentyfirst century. Our results demonstrated that the spatiotemporal trends in culture potential was species-specific. Finfish was less affected than bivalves. Four finfish species and seven bivalve species showed a continuously declining trend in culture potential and most species showed a northward shift of the centroid with high growth potential under SSP5-8.5. Under the scenario SSP1-2.6, the culture potential of finfish species mostly showed a stable or increasing trend, while that of bivalve species declined in the mid-twentyfirst century and partially recovered in the late twentyfirst century. Cold-water species exhibited a greater loss of culture potential than warm-water and eurythermal species. In the SSP5-8.5 and SSP1-2.6 scenarios, the cold-water species Oncorhynchus mykiss and Patinopecten yessoensis experienced the most significant loss in culture potential among finfish and bivalve species. Meanwhile, the culture potential for two out of the four warm-water species, specifically Epinephelus spp. and Sciaenops ocellatus, saw an increase. The culture potential for eight eurythermal species remained stable or declined. This study helps to identify mariculture potential for different species and sea areas and can inform the development of climate-resilient mariculture in China.

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As coenzymes, B vitamins have long been studied by marine researchers. Numerous studies have been conducted on the regulation of phytoplankton communities and algal–bacterial symbiosis. However, the key role of B vitamins in marine ecosystems has not received much attention. Through documents retrieval and genetic database analysis, we concluded the sources of vitamin B₁, B₂, B₆, B₇, and B₁₂ in the ocean and proposed their roles in marine ecosystem. Our review analysis demonstrated that producers and consumers of B vitamins are widespread in the ocean, and phytoplankton biomass and community structure are highly responsive to B vitamins. Unfortunately, the B vitamins concentration in seawater is extremely low and has been measured in very few sea areas. We have also shown that marine fish suffer from a wide variety of B vitamin deficiency symptoms when lacking sufficient B vitamins, suggesting that vitamin B restrictions are important for marine fish. On the other hand, fish provides many micronutrients that affect human health, especially for people whose primary diet is fish. We believe that B vitamins in the ocean affect marine ecosystems and fishery resources and, in turn, human health through a bottom-up approach. There are too many unknowns about the role of B vitamins in marine ecosystems, so we recommend more research on the distribution, function, and transfer of B vitamins in the ocean, as well as their effect on fishery resources.