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Thanks to the availability of the MEDITS survey data, a standardized picture of the occurrence and abundance of demersal Chondrichthyes in the northern Mediterranean has been obtained. During the spring-summer period between 2012 and 2015, 41 Chondrichthyes, including 18 sharks (5 orders and 11 families), 22 batoids (3 orders and 4 families) and 1 chimaera, were detected from several geographical sub-areas (GSAs) established by the General Fisheries Commission for the Mediterranean. Batoids had a preferential distribution on the continental shelf (10-200 m depth), while shark species were more frequent on the slope (200-800 m depth). Only three species, the Carcharhiniformes Galeus melastomus and Scyliorhinus canicula and the Torpediniformes Torpedo marmorata were caught in all GSAs studied. On the continental shelf, the Rajidae family was the most abundant, being represented in primis by Raja clavata and then by R. miraletus, R. polystigma and R. asterias. The slope was characterized by the prevalence of G. melastomus in all GSAs, followed by S. canicula, E. spinax and Squalus blainville. Areas under higher fishing pressure, such as the Adriatic Sea and the Spanish coast (with the exception of the Balearic Islands), show a low abundance of chondrichthyans, but other areas with a high level of fishing pressure, such as southwestern Sicily, show a high abundance, suggesting that other environmental drivers work together with fishing pressure to shape their distribution. Results of generalized additive models highlighted that depth is one of the most important environmental drivers influencing the distribution of both batoid and shark species, although temperature also showed a significant influence on their distribution. The approach explored in this work shows the possibility of producing maps modelling the distribution of demersal chondrichthyans in the Mediterranean that are useful for the management and conservation of these species at a regional scale. However, because of the vulnerability of these species to fishing exploitation, fishing pressure should be further incorporated in these models in addition to these environmental drivers.

Fisheries are an essential ecosystem service, but catches from freshwaters are often overlooked. Hundreds of millions of people around the world benefit from low-cost protein, recreation, and commerce provided by freshwater fisheries, particularly in regions where alternative sources of nutrition and employment are scarce. Here, we derive a gridded global map of riverine fisheries and assess its implications for biodiversity conservation, fishery sustainability, and food security. Catches increase with river discharge and human population density, and 90% of global catch comes from river basins with above-average stress levels. Fish richness and catches are positively but not causally correlated, revealing that fishing pressure is most intense in rivers where potential impacts on biodiversity are highest. Merging our catch analysis with nutritional and socioeconomic data, we find that freshwater fisheries provide the equivalent of all dietary animal protein for 158 million people. Poor and undernourished populations are particularly reliant on inland fisheries compared with marine or aquaculture sources. The spatial coincidence of productive freshwater fisheries and low food security highlights the critical role of rivers and lakes in providing locally sourced, low-cost protein. At the same time, intensive fishing in regions where rivers are already degraded by other stressors may undermine efforts to conserve biodiversity. This syndrome of poverty, nutritional deficiency, fishery dependence, and extrinsic threats to biodiverse river ecosystems underscores the high stakes for improving fishery management. Our enhanced spatial data on estimated catches can facilitate the inclusion of inland fisheries in environmental planning to protect both food security and species diversity.

This review focuses on the recent data on Mediterranean fishing fleets and landings, results from stock assessments and ecosystem models to provide an overview of the multiple impacts of fishing exploitation in the different Mediterranean geographical sub-areas (GSAs). A fleet of about 73.000 vessels is widespread along the Mediterranean coasts. Artisanal activities are predominant in South Mediterranean and in the eastern basin, while trawling features GSAs in the western basin and the Adriatic. The overall landings of fish, crustaceans and cephalopods, after peaking during mid ‘90s at about one million tons, declined at about 700.000 in 2013. However, while landings are declining in EU countries since the 90s, in non-EU a decreasing trend was observed only in the last 5-10 years. The current levels of fishing effort determine a general overexploitation status of commercial stocks with more than 90% of the stock assessed out of safe biological limits. Indicators obtained from available ecosystem models included primary production required to sustain fisheries (PPR), mean trophic level of the catch (mTLc), the loss in secondary production index (L index) and the probability of the ecosystem to be sustainably fished (psust). In areas exploited sustainably (e.g. Gulf of Gabes, Eastern Ionian and Aegean Sea) fishing pressure was characterized by either low number of vessels per unit of shelf area or the large prevalence of artisanal/small scale fisheries. Conversely, GSAs in Western and Adriatic showed very low ecosystem sustainability of fisheries that can be easily related with the high fishing pressure and the large proportion of overfished stocks obtained from single species assessments. We showed that the current knowledge on Mediterranean fisheries and ecosystems depict a worrisome picture where the effect of poorly regulated fisheries, in combination with the ongoing climate forcing and the rapid expansion of non-indigenous species, are rapidly changing the structure and functioning of the ecosystem with unpredictable effects on the goods and services provided. Although this would call for urgent conservation actions, the management system implemented in the region appears too slow and probably inadequate to protect biodiversity and secure fisheries resources for the future generations.

Coral reefs are subjected to unprecedented levels of disturbance with population growth and climate change combining to reduce standing coral cover and stocks of reef fishes. Most of the damage is concentrated in shallow waters (<30 m deep) where humans can comfortably operate and where physical disturbances are most disruptive to marine organisms. Yet coral reefs can extend to depths exceeding 100 m, potentially offering refuge from the threats facing shallower reefs. We deployed baited remote underwater stereo-video systems (stereo-BRUVs) at depths of 10–90 m around the southern Mariana Islands to investigate whether fish species targeted by fishing in the shallows may be accruing benefits from being at depth. We show that biomass, abundance and species richness of fishery-targeted species increased from shallow reef areas to a depth of 60 m, whereas at greater depths, a lack of live coral habitat corresponded to lower numbers of fish. The majority of targeted species were found to have distributions that ranged from shallow depths (10 m) to depths of at least 70 m, emphasising that habitat, not depth, is the limiting factor in their vertical distribution. While the gradient of abundance and biomass versus depth was steepest for predatory species, the first species usually targeted by fishing, we also found that fishery-targeted herbivores prevailed in similar biomass and species richness to 60 m. Compared to shallow marine protected areas, there was clearly greater biomass of fishery-targeted species accrued in mesophotic depths. Particularly some species typically harvested by depth-limited fishing methods (e.g., spearfishing), such as the endangered humphead wrasse Cheilinus undulatus , were found in greater abundance on deeper reefs. We conclude that mesophotic depths provide essential fish habitat and refuge for fishery-targeted species, representing crucial zones for fishery management and research into the resilience of disturbed coral reef ecosystems.

Over the past decades, Atlantic salmon (Salmo salar, Salmonidae) has emerged as a model system for sexual maturation research, owing to the high diversity of life history strategies, knowledge of trait genetic architecture, and their high economic value. The aim of this synthesis is to summarize the current state of knowledge concerning maturation in Atlantic salmon, outline knowledge gaps, and provide a roadmap for future work. We summarize the current state of knowledge: 1) maturation in Atlantic salmon takes place over the entire life cycle, starting as early as embryo development, 2) variation in the timing of maturation promotes diversity in life history strategies, 3) ecological and genetic factors influence maturation, 4) maturation processes are sex-specific and may have fitness consequences for each sex, 5) genomic studies have identified large-effect loci that influence maturation, 6) the brain-pituitary–gonadal axis regulates molecular and physiological processes of maturation, 7) maturation is a key component of fisheries, aquaculture, conservation, and management, and 8) climate change, fishing pressure, and other anthropogenic stressors likely have major effects on salmon maturation. In the future, maturation research should focus on a broader diversity of life history stages, including early embryonic development, the marine phase and return migration. We recommend studies combining ecological and genetic approaches will help disentangle the relative contributions of effects in different life history stages to maturation. Functional validation of large-effect loci should reveal how these genes influence maturation. Finally, continued research in maturation will improve our predictions concerning how salmon may adapt to fisheries, climate change, and other future challenges.

Climate change is driving changes in the physical and chemical properties of the ocean that have consequences for marine ecosystems. Here, we review evidence for the responses of marine life to recent climate change across ocean regions, from tropical seas to polar oceans. We consider observed changes in calcification rates, demography, abundance, distribution and phenology of marine species. We draw on a database of observed climate change impacts on marine species, supplemented with evidence in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We discuss factors that limit or facilitate species’ responses, such as fishing pressure, the availability of prey, habitat, light and other resources, and dispersal by ocean currents. We find that general trends in species responses are consistent with expectations from climate change, including poleward and deeper distributional shifts, advances in spring phenology, declines in calcification and increases in the abundance of warm-water species. The volume and type of evidence of species responses to climate change is variable across ocean regions and taxonomic groups, with much evidence derived from the heavily-studied north Atlantic Ocean. Most investigations of marine biological impacts of climate change are of the impacts of changing temperature, with few observations of effects of changing oxygen, wave climate, precipitation (coastal waters) or ocean acidification. Observations of species responses that have been linked to anthropogenic climate change are widespread, but are still lacking for some taxonomic groups (e.g., phytoplankton, benthic invertebrates, marine mammals).

Hoque, M.; Ramteke, K.; Nakhawa, A.D.; Abidi, Z.J., and Naidu, B.C., 2024. Vulnerability assessment of commercially essential fish stocks in the data-poor northwest coast of India. Journal of Coastal Research, 40(6), 1068–1079. Charlotte (North Carolina), ISSN 0749-0208. A semiquantitative risk assessment tool, such as the productivity susceptibility analysis (PSA), is widely used to evaluate the relative vulnerability of species to overfishing or other fishing activities. This tool is particularly valuable in data-poor regions for prioritizing conservation and research management efforts among different species. In the present study, PSA evaluated the vulnerability of 70 commercially essential finfish species, including 35 pelagic species and 35 demersal species. For the demersal species, the vulnerability score varied from 0.9 to 2. The spotted eagle ray (Aetobatus narinari) was identified as the most vulnerable species among selected demersal species, with a vulnerability score of 2, whereas the black pomfret (Parastromateus niger) exhibited the lowest vulnerability, with a score of 0.9. Among the demersal species, four species (11.42%) were classified as having moderate vulnerability, with scores ranging from 1.8 to 1.9, whereas 30 species (85.71%) were classified as having low vulnerability, with scores ranging from 0.9 to 1.7. The vulnerability scores of the 35 pelagic fishes ranged from 0.9 to 1.9. The lowest vulnerability score, 0.9, was observed in the Indian oil sardine Sardinella longiceps and commerson's anchovy Stolephorus commersoni; the great barracuda Spyraena barracuda showed the highest vulnerability score, 1.9, among 35 pelagic fishes from the NW coast of India. Most of the overall data quality (DQ) were selected from moderate DQ from the present study. The susceptibility DQ for most species is low; this suggests that data collection on certain species' life-history features should be improved. Vulnerability evaluation is useful in identifying species that face extinction or overexploitation. The results of this study will help in planning fisheries management programs and creating conservation strategies.

Two nektonic squid species, Illex argentinus in the Southwest Atlantic and Dosidicus gigas in the Eastern Pacific, are amongst the largest commercial cephalopod resources; presently comprising from one third to almost one half of the global cephalopod catch. These squids are straddling stocks exploited during their ontogenetic migrations both within exclusive economic zones of coastal States and in adjacent high seas. At present, fisheries of these squids lack an agreement to undertake comprehensive international stock assessments and management, resulting in minimal data exchanges among coastal States and those fishing in the high seas. In the high seas, there is little to no regulation and control of fishing activities, with very limited information on catch and effort. However, the high seas have been very important for commercial exploitation of both species, with annual averages of 45% of the total I. argentinus catch and 30–40% of the total D. gigas catch over the last decade. With uncontrolled harvest in the high seas, and without any unified international regulation, these straddling squid resources are highly vulnerable to overfishing; especially during years of poor recruitment and low abundance. Recent dramatic increases of fishing pressure pose a significant threat to the sustainability of these globally important squid resources. A proposal to reduce the risk of squid stocks depletion would be the establishment of a multi-national advisory forum to explicitly monitor stocks, coordinate assessment of population dynamics, and provide management recommendations for cephalopod fisheries around the world.

Considerable empirical evidence supports recovery of reef fish populations with fishery closures. In countries where full exclusion of people from fishing may be perceived as inequitable, fishing-gear restrictions on nonselective and destructive gears may offer socially relevant management alternatives to build recovery offish biomass. Even so, few researchers have statistically compared the responses of tropical reef fisheries to alternative management strategies. We tested for the effects of fishery closures and fishing gear restrictions on tropical reef fish biomass at the community and family level. We conducted 1,396 underwater surveys at 617 unique sites across a spatial hierarchy within 22 global marine ecoregions that represented 5 realms. We compared total biomass across local fish assemblages and among 20 families of reef fishes inside marine protected areas (MPAs) with different fishing restrictions: no-take, hook-and-line fishing only, several fishing gears allowed, and sites open to all fishing gears. We included a further category representing remote sites, wherefishing pressure is low. As expected, full fishery closures, (i.e., no-take zones) most benefited communityand family-level fish biomass in comparison with restrictions on fishing gears and openly fished sites. Although biomass responses to fishery closures were highly variable across families, some fishery targets (e.g., Carcharhinidae and Lutjanidae) respondedpositively to multiple restrictions on fishing gears (i.e., where gears other than hook and line were not permitted). Remoteness also positively affected the response of community-level fish biomass and many fish families. Our findings provide strong support for the role of fishing restrictions in building recovery offish biomass and indicate important interactions among fishing-gear types that affect biomass of a diverse set of reef fish families. Hay fuertes evidencias empíricas que respaldan la recuperación de las poblaciones de peces de arrecifes con el cierre de las pesquerías. En los países en los que la exclusión total de pescadores puede ser percibida como injusta, las restricciones de equipos de pesca para equipos no selectivos y destructivos pueden ofrecer alternativas de manejo socialmente relevantes para construir la recuperación de la biomasa de los peces. Aún así, pocos investigadores han comparado estadísticamente las respuestas de las pesquerías de peces tropicales de arrecifes a las estrategias de manejo alternativo. Probamos los efectos de los cierres de las pesquerías y las restricciones del equipo de pesca sobre la biomasa de peces tropicales a nivel familia y a nivel comunidad. Realizamos 1,396 censos submarinos en 617 sitios únicos a través de una jerarquía espacial dentro de 22 ecoregiones marinas mundiales que representaron cinco ámbitos. Comparamos la biomasa total entre los grupos de peces locales y entre 20 familias de peces de arrecife dentro de áreas marinas protegidas (AMP) con diferentes restricciones para la pesca: pesca prohibida, pesca de anzuelo y sedal únicamente, varios equipos de pesca permitidos, y sitios abiertos a todo tipo de equipos de pesca. Incluimos una categoría más que representó a los sitios remotos, en donde la presión por la pesca es baja. Como se esperaba, el cierre total de las pesquerías (es decir, zonas de pesca prohibida) benefició más a nivel de la comunidad y de la familia la biomasa de los peces en comparación con las restricciones para los equipos de pesca y los sitios con pesca abierta. Aunque las respuestas en la biomasa al cierre de las pesquerías fueron altamente variables entre familias, algunos objetivos de la pesca (p. ej.: Carcharinidae y Lutjanidae) respondieron positivamente a las restricciones múltiples para los equipos de pesca (es decir, en donde no estaban permitidos otros equipos además del sedal y el anzuelo). La lejanía también afectó positivamente la respuesta de la biomasa de peces a nivel de comunidad y de muchas familias. Nuestros resultados proporcionan un fuerte respaldo para el papel de las restricciones de pesca en la construcción de la recuperación de la biomasa de peces e indican interacciones importantes entre los tipos de equipos de pesca que afectan a la biomasa de un conjunto diverso de familias de peces de arrecife.