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Overexploitation has led to large scale declines in many fish stocks around the world with the 2030 United Nations agenda calling for more spatial management tools to achieve sustainability targets. However, without spatially explicit consideration of fisheries dynamics, assessment of management measures combining spatial temporal closures and effort reduction measures remain limited. This is particularly true when balancing population biomass recovery goals and their socioeconomic consequences. Using ISIS-Fish, the first spatially explicit bioeconomic model describing hake (Merluccius merluccius) fisheries in the Gulf of Lion, Mediterranean Sea, we investigated the consequences of individual spatial temporal closures and spatial closure network effects with all-at-one and gradual effort reduction measures. Their effectiveness in restoring the collapsed population and economic objectives were quantified to identify measures best suited for rebuilding population biomass, increasing catch weight, and maintaining revenue levels. While severe effort reduction was more effective in achieving population recovery goals than spatial temporal closures, these scenarios did not lead to an increase in catches until after five years. In contrast, spatial temporal closures failed to reach population recovery goals at any point during the simulation period, but impacted revenues the least. Simulated effort redistribution also led to greater depletion of juvenile hake, a pattern common elsewhere in the world. The present study illustrates how robust spatially explicit models may be used to evaluate the impacts of complex alternative management scenarios and to identify tradeoffs between biomass recovery, fishery viability, and the management equitability (and acceptability) between fishing fleets. • A 30–40% reduction in effort restored hake catches and stock biomass in the Gulf of Lion within 5 years. • Accounting for fleet spatial dynamics strengthens management of juvenile bycatch. • Regional biomass and catch patterns are driven by m´etier fishing effort reallocation. • Spatial closures without equal measure of effort reduction can limit stock recovery. • Spatial closures may offset costs incurred from loss of fishing opportunities. [ABSTRACT FROM AUTHOR]

Increasing impacts of both fisheries and climate change have resulted in shifts in the structure and functioning of marine communities. One recurrent observation is the rise of cephalopods as fish recede. This is generally attributed to the removal of main predators and competitors by fishing, while mechanistic evidence is still lacking. In addition, climate change may influence cephalopods due to their high environmental sensitivity. We aim to unveil the effects of different anthropogenic and environmental drivers at different scales focusing on the cephalopod community of the Western Mediterranean Sea. We investigate several ecological indicators offering a wide range of information about their ecology, and statistically relating them with environmental, biotic and fisheries drivers. Our results highlight non-linear changes of indicators along with spatial differences in their responses. Overall, the environment drivers have greater effects than biotic and local human impacts with contrasting effects of temperature across the geographic gradient. We conclude that cephalopods may be impacted by climate change in the future while not necessary through positive warming influence, which should make us cautious when referring to them as generalized winners of current changes. • Effects of environmental, biotic and human drivers were investigated for ecological indicators of cephalopods. • Dynamics of this taxon are mainly influenced by sea temperature, explaining geographical gradients in several metrics. • Relationships with biotic variables could hint at the decrease of high trophic fishes. • Fishing has little effect on cephalopods with β-diversity being the only indicator influenced by this variable. • Potential negative effects of warming on indicators challenge the idea of cephalopods as a climate change winners. [ABSTRACT FROM AUTHOR]

The deep sea plays a critical role in global climate regulation through uptake and storage of heat and carbon dioxide. However, this regulating service causes warming, acidification and deoxygenation of deep waters, leading to decreased food availability at the seafloor. These changes and their projections are likely to affect productivity, biodiversity and distributions of deep‐sea fauna, thereby compromising key ecosystem services. Understanding how climate change can lead to shifts in deep‐sea species distributions is critically important in developing management measures. We used environmental niche modelling along with the best available species occurrence data and environmental parameters to model habitat suitability for key cold‐water coral and commercially important deep‐sea fish species under present‐day (1951–2000) environmental conditions and to project changes under severe, high emissions future (2081–2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean. Our models projected a decrease of 28%–100% in suitable habitat for cold‐water corals and a shift in suitable habitat for deep‐sea fishes of 2.0°–9.9° towards higher latitudes. The largest reductions in suitable habitat were projected for the scleractinian coral Lophelia pertusa and the octocoral Paragorgia arborea, with declines of at least 79% and 99% respectively. We projected the expansion of suitable habitat by 2100 only for the fishes Helicolenus dactylopterus and Sebastes mentella (20%–30%), mostly through northern latitudinal range expansion. Our results projected limited climate refugia locations in the North Atlantic by 2100 for scleractinian corals (30%–42% of present‐day suitable habitat), even smaller refugia locations for the octocorals Acanella arbuscula and Acanthogorgia armata (6%–14%), and almost no refugia for P. arborea. Our results emphasize the need to understand how anticipated climate change will affect the distribution of deep‐sea species including commercially important fishes and foundation species, and highlight the importance of identifying and preserving climate refugia for a range of area‐based planning and management tools. [ABSTRACT FROM AUTHOR]

SUMMARY: Trawling activities are considered to be one of the main sources of disturbance to the seabed worldwide. We aimed to disentangle the dominance of environmental variations and trawling intensity in order to explain the distribution of diversity patterns over 152 sampling sites in the French trawl fishing-ground, the Grande Vasière. Using a towed underwater video device, we identified 39 taxa to the finest taxonomic level possible, which were clustered according to their vulnerability to trawling disturbance based on functional traits. Using generalized linear models, we investigated whether the density distribution of each vulnerability group was sensitive to trawling intensity and habitat characteristics. Our analyses revealed a structuring effect of depth and substratum on community structure. The distribution of the more vulnerable group was a negative function of trawling intensity, while the distributions of the less vulnerable groups were independent of trawling intensity. Video monitoring coupled with trait-based vulnerability assessment of macro-epibenthic communities might be more relevant than the traditional taxonomic approach to identifying the areas that are most vulnerable to fishing activities in conservation planning. [ABSTRACT FROM AUTHOR]

Various environmental parameters such as temperature, depth and currents influence the composition and distribution of benthic assemblages. However, the impact of trawling on benthic communities depends on their species composition since not all benthic species are equally sensitive to trawling. Moreover, trawling can have effects on benthic species similar to some natural disturbances, such as a local increase in turbidity. Thus, species adapted to these natural disturbances may be resistant to a certain level of trawling. This study evaluates the joint influence of environmental parameters and trawling pressure on four functional sensitivity indices in three environmentally contrasted areas: the English Channel, the Gulf of Lion and the eastern coast of Corsica, the two latter being located in the Mediterranean Sea. The different environmental parameters influencing the behaviour of these indices were identified in each of the study areas. These parameters were divided into two groups according to the type of influence they have on the benthic community. The first group of variables, used for modeling "Scope for Growth" (SfG), relates to the resilience of species, while the second, "Disturbance" (Dist), concerns their resistance to physical impacts. This work highlighted that the distribution of benthic species in the English Channel is mainly linked to physical disturbances and therefore to their resistance, whereas it is mainly parameters linked to the resilience of communities that influence the distribution of benthic fauna in the Mediterranean. The effect of abrasion could be distinguished from the natural environmental disturbances in the English Channel and Gulf of Lion where trawling was found to have a significant effect on functional sensitivity indices. The composition and distribution of benthic communities in Corsica, did not seem to be influenced by trawling pressure. • The joint influence of environmental parameters and trawling pressure on four functional sensitivity indices in three environmentally contrasted areas (English Channel, Gulf of Lion, Corsica) was evaluated. • Environmental variables were classified in two groups according to the type of influence they have on the benthic community (resilience vs. resistance). • The distribution of benthic species in the English Channel appear to be linked to physical disturbances and therefore to their resistance. • In the Mediterranean Sea, the distribution of benthic fauna seems to be due to parameters linked to the resilience of communities. • The effect of abrasion can be distinguished from the natural environmental disturbances in the English Channel and Gulf of Lion. [ABSTRACT FROM AUTHOR]

Many indicators have been developed to assess the state of benthic communities and identify seabed habitats most at risk from bottom trawling disturbance. However, the large variety of indicators and their development and application under specific geographic areas and management contexts has made it difficult to evaluate their wider utility. We compared the complementarity/uniqueness, sensitivity, and selectivity of 18 benthic indicators to pressure of bottom trawling. Seventeen common datasets with broad regional representation covering a range of pressure gradients from bottom trawling disturbance (n = 14), eutrophication (n = 1), marine pollution (n = 1), and oxygen depletion (n = 1) were used for the comparison. The outcomes of most indicators were correlated to a certain extent with response to bottom trawling disturbance, and two complementary groups of indicators were identified: diversity-based and biological trait-based indicators. Trait-based indicators that quantify the changes in relative abundance of sensitive taxa were most effective in identifying benthic community change in response to bottom trawling disturbance. None of the indicators responded to the trawling pressure gradient in all datasets, and some showed a response that were opposed to the theoretical expectation for some gradients. Indicators that showed clear responses to bottom trawling disturbance also showed clear responses in at least one other pressure gradient, suggesting those indicators are not pressure specific. These results emphasize the importance of selecting several indicators, at least one from each group (diversity and trait-based), to capture the broader signals of change in benthic communities due to bottom trawling activities. Our systematic approach offers the basis from which scientific advisors and/or managers can select suitable combinations of indicators to arrive at a sensitive and comprehensive benthic status assessment., (© 2024 The Author(s). Ecological Applications published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)

The bamboo-coral Isidella elongata is a key habitat-forming species in the deep Mediterranean Sea. This alcyonacean is listed as an indicator of Vulnerable Marine Ecosystems (VMEs) and as Critically Endangered due to bottom trawling impacts. In this work, a modeling approach was used to predict and map the habitat suitability of I. elongata in the Mediterranean Sea under current environmental conditions. Occurrence data were modeled as a function of environmental parameters. Using climate change scenarios and fishing effort data, the risk of climate change and fisheries impacts on habitat suitability were estimated, and climate refugia were identified. A drastic loss of habitat is predicted, and climate change scenarios suggest a loss of 60% of suitable habitats by 2100. In the central Mediterranean, climate refugia overlapped with active fishing grounds. This study represents the first attempt to identify hot spots for the protection of soft bottom Vulnerable Marine Ecosystems for the entire Mediterranean Sea, and highlights areas most at risk from trawling. This work is relevant to the objectives of the EU Marine Strategy Framework and Maritime Spatial Planning Directives, the Biodiversity Strategy for 2030 regarding priority areas for conservation., (© 2024. The Author(s).)