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In the context of the marine ecosystem ecological crisis, assessing the sustainability performance of fisheries has become a priority. Using European tropical tuna purse seine fleets as a case study, we show how a multidisciplinary dashboard approach can be used to determine historical and current sustainability performances of fishing fleets to improve understanding of the links between the multiple dimensions of sustainability and to highlight management policy priorities. Based on a set of 18 indicators and using a principal component analysis method, we evaluated the environmental, economic and social sustainability performances of these fleets. We compared the average fleet performances for 2015–2019 with the other tuna fishing fleets in the Atlantic and Indian Oceans. We then analysed the evolution of sustainability performance of European tuna purse seiners from 2009 to 2019.Our results illustrate that the purse seiners currently fishing the Indian Ocean have better ecological performances than those fishing the Atlantic, thanks to healthier tuna stocks. Performance related to impacts on marine ecosystems contrasts between tuna fishing gears. Purse seiners, especially those fishing on free school, were more selective than other gears. From 2009 to 2019, their economic performance increased while their social performance stabilised. The recent development of the use of fish aggregating devices (FADs), to the detriment of free school fishing strategy caused a loss of performance in ecology and social dimensions. Purse seiners fishing on FADs had more juvenile tuna catches, lower species selectivity, a higher carbon footprint and a lower average salary for fishermen. Fishing on FADs implied a higher fuel consumption, which is one of the major expenses for fishing fleets. Our results confirm that it is ecologically and economically justified to incite purse seine fleets to reduce fishing on FADs.

This data includes indicators estimated in a multicriteria dashboard study applied to assess sustainability of tropical tuna fisheries in Atlantic and Indian Oceans. The objective of this work was to test a multidimensional approach, accounting for the ecological, economic and social dimensions of fisheries sustainability, with the case study of tropical tuna fishing fleets. This dashboard has been constructed based on a bibliography review then calculated annually for all historical period available. Main sources for raw data were Regional Fisheries Management Organisation’s (RFMO) public data for the majority of ecological indicators and the Data Collection Framework (Regulation (EC) 199/2008) for economic, social indicators and one ecologic indicator (Fuel Use Intensity or FUI). The dashboard gathers 21 indicators (14 ecological, 4 economic and 3 social indicators) for which we presented here their estimated values for our case study. According to raw data availability, the majority of ecological indicators were calculated from 1950 to 2020 for 102 fleets operating in Atlantic and Indian Oceans, while FUI, economic and social indicators were calculated only for the European purse seiners and longliners (French and Spanish) over a shorter period of time (2009-2019) than the one for ecological indicators. Because the raw data from the Data collection framework were aggregated, a disaggregation method based on the allocation of the fishing effort to each ocean, was applied to each fleet segment. This dataset is a tool to monitor the sustainability performance of tuna fisheries and can be re-used to compare performances between fishing gears, time periods and fishing practices by flag.

Since the 1980s, the Common Fisheries Policy (CFP) has shaped European fisheries. It has often been criticised for being too prescriptive and, above all, for failing to protect either fishermen or ecosystems. The last reform dates back to the early 2010 s and has led to a slight but slow improvement in the state of ecosystems. Given that the CFP is in the process of evaluation, a group of French fishery scientists set up an initiative to add to the debate on what should be retained, reinforced or added to a possible new reform. This initiative came 10 years after a previous manifesto that presented their vision for fisheries in Europe. Four major issues emerged from the current initiative: (1) a need for transMots-clés parency and simplification in fisheries management, (2) a need for more consultation and dialogue between stakeholders, (3) the urgency of the situation in the Mediterranean Sea, and (4) the necessity of putting into practice all research developments for an ecosystem approach to fisheries. Compared to 10 years ago, the response of scientists shows that the focus is no longer on achieving the maximum sustainable yield, but rather on the following steps to protect ecosystems and fisheries. An ecosystem approach to fisheries remains indispensable for both ecosystems and fishing activities. To this end, scientists put forward numerous proposals to improve the CFP, acknowledging that the final solutions should emerge from consultation with stakeholders. Climate change, an issue raised much more than in the manifest, reinforces the need to act.

Climate change is warming the ocean and impacting lower trophic level (LTL) organisms. Marine ecosystem models can provide estimates of how these changes will propagate to larger animals and impact societal services such as fisheries, but at present these estimates vary widely. A better understanding of what drives this inter-model variation will improve our ability to project fisheries and other ecosystem services into the future, while also helping to identify uncertainties in process understanding. Here, we explore the mechanisms that underlie the diversity of responses to changes in temperature and LTLs in eight global marine ecosystem models from the Fisheries and Marine Ecosystem Model Intercomparison Project (FishMIP). Temperature and LTL impacts on total consumer biomass and ecosystem structure (defined as the relative change of small and large organism biomass) were isolated using a comparative experimental protocol. Total model biomass varied between −35% to +3% in response to warming, and -17% to +15% in response to LTL changes. There was little consensus about the spatial redistribution of biomass or changes in the balance between small and large organisms (ecosystem structure) in response to warming, an LTL impacts on total consumer biomass varied depending on the choice of LTL forcing terms. Overall, climate change impacts on consumer biomass and ecosystem structure are well approximated by the sum of temperature and LTL impacts, indicating an absence of nonlinear interaction between the models’ drivers. Our results highlight a lack of theoretical clarity about how to represent fundamental ecological mechanisms, most importantly how temperature impacts scale from individual to ecosystem level, and the need to better understand the two-way coupling between LTL organisms and consumers. We finish by identifying future research needs to strengthen global marine ecosystem modelling and improve projections of climate change impacts.

Analyzing the long-term changes in ecosystems and disentangling the influence of overfishing and environment require historical data integration. Fisheries-independent data are available only since the mid-1980s in the Celtic Sea and thus provide a short-term and truncated vision of fishing impacts. We conducted a catch-based study over the 1950–2015 period. We successively (i) reconstituted catch time-series, including unreported catch estimates, and studied them through a trophic-spectrum approach and ecosystem indicators based on trophic level, size and species diversity; (ii) estimated biomass trends of the main Celtic Sea target species from catch and effort time-series, using production models that detect potential shifts in productivity; and (iii) explored linkages between species productivity potential and both fishing and environment using long-term time-series of large-scale climatic indices, locally observed hydroclimatic variables and plankton data from the Continuous Plankton Recorder. Our results highlight that fishing has caused a drastic depletion of the main exploited species in the Celtic Sea since World War II. The biomass reduction of larger demersal species may reach more than 80 %; additionally, this depletion occurred earlier than previously thought and may have initiated a trophic cascade in the ecosystem. North Atlantic hydroclimatic variability affected species productivity, worsening the early stock depletion while potentially mitigating fishing impact in the 1990s. The common pattern in productivity changes among analyzed species highlights an abrupt transition whose timing matches that of the ecosystem shifts identified in several Atlantic ecosystems. Finally, we show that the recent fishing pressure reduction led by the European Common Fisheries Policy initiated a partial recovery of stocks and ecosystem status over the last decade.