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21 pages, 8 figures, 3 tables, supplementary material https://www.frontiersin.org/articles/10.3389/fmars.2021.570354/full#supplementary-material.-- Data Availability Statement: The datasets presented in this article are not readily available because the dataset is available by request to the Spanish Institute of Oceanography. Requests to access the datasets should be directed to webmaster@ieo.es ; Small pelagic fish (SPF) in the western Mediterranean Sea are key elements of the marine food web and are important in terms of biomass and fisheries catches. Significant declines in biomass, landings, and changes in the age/size structure of sardine Sardina pilchardus and anchovy Engraulis encrasicolus have been observed in recent decades, particularly in the northern area of the western Mediterranean Sea. To understand the different patterns observed in SPF populations, we analyzed key life history traits [total length at age, length at maturity, gonadosomatic index (GSI), and body condition (Kn)] of sardine and anchovy collected between 2003 and 2017, from different fishing harbors distributed along a latitudinal gradient from northern to southern Spain. We used Generalized Linear Models (GLM) to estimate the length at maturity and Generalized Additive Models (GAMs) to test the relationship with environmental variables (seawater temperature, water currents, and net primary productivity). The life history traits of both species presented seasonal, interannual and latitudinal differences with a clear decline in length at age, length at first maturity, and body condition, for both species in the northern part of the study area. In the southern part, on the contrary, life history traits did not present a clear temporal trend. The environmental conditions partially explained the long-term changes in life history traits, but the selected variables differed between areas, highlighting the importance of regional oceanographic conditions to understand the dynamics of small pelagic fish. The truncated length-at-age pattern for both species with the disappearance of the larger individuals of the population could have contributed to the poor condition of small pelagic fish populations in the northern part of the western Mediterranean Sea in recent years. In the south area, recent declines in body condition for sardine and anchovy were observed and could be a possible first sign for future population declines. This study highlights the importance of understanding the trade-off between the energy invested in reproduction, maintenance and growth at seasonal and interannual level to advance our knowledge on how environmental and human pressures influence population dynamics of small pelagic fish at local and regional scales ; This study was carried out within the Spanish Research project PELWEB (CTM2017-88939-R) funded by Spanish Ministry of Science, Innovation and Universities and the European Research Contract SPELMED (SC NR 02-TENDER EASME/EMFF/2016/032XXX) funded by EC EASME. Fisheries data collection has been co-funded by the EU through the European Maritime and Fisheries Fund (EMFF) within the National Program of collection, management and use of data in the fisheries sector and support for scientific advice regarding the Common Fisheries Policy (Regulation, EU 2017/1004) ; With funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S) ; Peer reviewed

EU fishing fleets in the West African region, "particularly the East European vessels, continue to disregard their obligations to embark scientific observers on board, while they fish unsustainably."

23 pages, 8 figures, 1 table, supplementary material https://doi.org/10.1007/s10584-020-02723-4 ; We studied the effect of climate change on the potential spawning habitats of two marine small pelagic fishes. We examined the projected changes in the potential spawning habitat of the summer-spawning anchovy (Engraulis encrasicolus) and round sardinella (Sardinella aurita) in the northwestern Mediterranean by combining the regionalized projections of RCP scenarios with an existing species distribution model (SDM). The SDM was based on a separate generalized additive model for the eggs and larvae of the two species computed from ichthyoplankton sampling that was conducted with simultaneous readings of surface temperature, salinity and chlorophyll-a values as predictor variables. The SDM was projected for the 2010 decade, which represented the present-day conditions, with these environmental variables obtained from the regionalized POLCOMS-ERSEM biogeochemical model forced by the RCP 4.5 and RCP 8.5 scenarios. The comparison of the present-day projection results with the projections for the middle and final decades of the twenty-first century showed that the suitability of the spawning habitat as defined by the anchovy eggs model was likely to increase over time under RCP4.5 or decrease slightly under RCP8.5, but the habitat for anchovy larvae was likely to decrease in all cases. Loss of habitat was projected to be particularly important in the south of the study area on the Ebre River delta continental shelf. Conversely, the probability of round sardinella occurrence will significantly increase under both scenarios. The potential habitat of this species, which is of subtropical origin, is likely to shift northwards. The limitations of the existing models to extrapolate the current results to future scenarios are discussed regarding (i) the uncertainty in the projections of driving environmental variables (e.g., chlorophyll-a), (ii) the simplified nature of the projection models, which did not capture the dynamics of the early life stages of the fish at a small scale, and (iii) insufficient consideration of important drivers, such as larval transport or retention by mesoscale hydrographic phenomena ; This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Grant Agreement "CERES" No. 678193 and from the Spanish Ministry of Economy and Competitiveness (CTM2010-18874 and CTM2015-68543-R). Eduardo Ramirez-Romero received funding from "Govern de les Illes Balears—Conselleria d'Innovació, Recerca i Turisme, Programa Vicenç Mut."

11 pages, 7 figures, supplementary data https://doi.org/10.1016/j.scitotenv.2020.144002 ; Sustainable fishing practices must ensure human wellbeing by safeguarding the integrity of marine life-supporting systems. Unfortunately, a significant challenge to fisheries management is that sustainable fishing levels can decline, often synergistically, by co-occurring with climate-driven environmental stressors. Within one of the most impacted marine areas in the world, and encompassing a number of highly targeted commercial species, the small pelagic fish community of the western Mediterranean Sea has recently shown signs of collapse. In this study, we identify a worrying coincidence where fishing hotspots for the commercially valuable European sardine Sardina pilchardus and anchovy Engraulis encrasicolus occur in marine areas mostly affected by climate change. To identify these areas, we overlayed detailed, spatially explicit measurements of fishing pressure with the finest-scale maps of cumulative climate change impacts onto these species. According to our results, doubly impacted marine areas largely occur in the north-western Mediterranean Sea, with climate and fisheries mostly affecting European sardine. Reducing local stressors (i.e., fishing pressure) in highly impacted areas may contribute to maintain these communities within a "safe operating space" (SOS), where they remain resilient to climate change. Accordingly, the redistribution and/or reduction of fishing intensity may alleviate pressure in those areas already affected by climate change. Sustainable fishing strategies may benefit, therefore, from the SOS concept and the spatial assessments provided in this study ; This study was carried out within the Spanish Research project PELWEB (CTM2017-88939-R) funded by Spanish Ministry of Science, Innovation and Universities, the Catalonian Government PELCAT projects (CAT 152CAT00013, TAIS ARP059/19/00005), and the study received funding from European Union's Horizon 2020 research and innovation programme under grant agreement No 817578 (TRIATLAS project) ; Peer reviewed

20 pages, 15 figures, supplementary material https://www.frontiersin.org/articles/10.3389/fmars.2020.00622/full#supplementary-material ; In the Northwestern Mediterranean Sea, the European sardine (Sardina pilchardus) and the European anchovy (Engraulis encrasicolus) are the most important small pelagic fish in terms of biomass and commercial interest. During the last years, these species have experimented changes in their abundance and biomass trends in the Northwestern Mediterranean Sea, in addition to changes in growth, reproduction and body condition. These species are particularly sensitive to environmental fluctuations with possible cascading effects as they play a key role in connecting the lower and upper trophic levels of marine food webs. It is therefore essential to understand the factors that most profoundly affect sardine and anchovy dynamics. This study used a two-step approach to understand how the environment influences the adult stages of these species in the Northwestern Mediterranean Sea. First, we explored the effects of environmental change over time using Random Forests and available datasets of species occurrence, abundance, biomass and landings. We then applied species distribution models to test the impact of the extreme pessimistic and optimistic Intergovernmental Panel on Climate Change (IPCC) pathway scenarios, and to identify possible climate refuges: areas where these species may be able to persist under future environmental change. Findings from the temporal modeling showed mixed effects between environmental variables and for anchovy and sardine datasets. Future pathway projections highlight that both anchovy and sardine will undergo a reduction in their spatial distributions due to future climate conditions. The future climate refuges are the waters around the Rhone River (France) and the Ebro River (Spain) for both species. This study also highlights important knowledge gaps in our understanding of the dynamics of small pelagic fish in the region, which is needed to progress towards an ecosystem approach to fisheries management ; This study was carried out within the Spanish Research project PELWEB (CTM2017-88939-R) funded by the Spanish Ministry of Science, Innovation and Universities, the European Research Contract SPELMED (EASME/EMFF/2016/032) funded by the ECEASME and the Catalonian Government PELCAT projects (CAT 152CAT00013 and TAIS ARP059/19/00005) ; Peer reviewed

The release of unwanted catches (UWC) from purse seines, while the catch is still in the water, is known as "slipping". Once thought to be a benign process, compared to discarding UWC overboard from the fishing vessel, it is now recognised that "slipping" can lead to significant mortality in the released fish if done inappropriately. In this chapter, we examine purse seining and slipping operations, and discuss what drives slipping and potential mitigation measures to reduce slipping mortality. We use three examples of purse seine fisheries for small pelagic species in the North-east Atlantic; from Norway, Portugal and Spain. The ideal solution (identifying and avoiding UWC before the net is set) requires the development of tools to enable fishers to better characterise target schools in terms of key selection criteria, e.g., with respect to species, individual size and catch biomass. Such tools are being developed, based primarily on hydro-acoustic technology. However, some UWC in purse seine catches are inevitable, and operational improvements in slipping practices have been shown to significantly reduce stress and mortality in the released UWC. We conclude with a discussion on the challenges currently facing the implementation of the European Union (EU) Landing Obligation with regards to minimising slipping related mortality. ; info:eu-repo/semantics/publishedVersion

10 pages, 4 figures, 6 tables, supplementary data https://doi.org/10.1016/j.ecss.2021.107699 ; Sardine and anchovy have shown important changes in landings, biomass, abundance and body condition with time in the Western Mediterranean Sea. Several hypotheses have been proposed to explain these changes, including the negative interaction with jellyfish blooms. Increases in jellyfish blooms may be one of the reasons for a decline in these fish stocks because several jellyfish species have been shown to feed on fish larvae and juveniles. The main aim of the present study was to test the plausible relationship between jellyfish blooms and stock dynamics (abundance, biomass, and fitness) of anchovy and sardine, and its fisheries within an ecological context of the western Mediterranean Sea. Our main hypothesis was that jellyfish blooms, in combination with other environmental drivers, could have negative effects due to their predation on early stages of small pelagic fish (direct mortality) or due to predation on zooplankton, which is also prey of the small pelagic fish at different ontogenetic stages (direct competition). To test our hypothesis, we developed Bayesian Generalized Linear Mixed Models to compare landings, biomass, abundance, and Kn condition factor of both species with several climatic indices, oceanographic variables, and the occurrences of jellyfish blooms. Our results revealed that the jellyfish bloom occurrence had a high probability of negatively and broadly affecting both species in addition to changes in environmental conditions. This suggests that jellyfish blooms should be added to the likely causes of change when analyzing small pelagic fish change ; This study was carried out within the Spanish Research project PELWEB (CTM2017-88939-R) funded by Spanish Ministry of Science, Innovation and Universities, and the Catalonian Government PELCAT projects (CAT 152CAT00013, TAIS ARP059/19/00005). [.] MC acknowledges the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S) to the Institute of Marine Science (ICM-CSIC). ; Peer reviewed

AbstractIndustrial fisheries targeting small pelagic fish have significant socio‐economic implications for North West African countries. This study examines the economic performance of fleets operating in Mauritania's exclusive economic zone under the free license and chartering systems. Using national production data from 1989 to 2010 and economic indicator ratios from European pelagic fishing vessels, we assess the economic performance of pelagic fisheries over one decade. Our findings show that vessel characteristics have rapidly evolved, with free‐licenced vessels having a higher average fishing capacity than chartered vessels. The nominal number of free licenses increased from under 8% in 1995; the year of free licencing began in Mauritania, to over 80% in 2010. The estimated average economic output for 2000–2010 was US$ 231 million, with free licenses contributing over 80% of the total turnover (US$ 187 million). Vessels operating under free licenses made a greater contribution to wealth creation than the chartering regime. Foreign ship owners generated US$ 40.7 million (22%) in income, while chartering yielded US$ 3.6 million (8%). However, the chartering regime was more fiscally advantageous, contributing over 68% of pelagic fisheries tax revenues (estimated at over US$ 29 million). The small pelagic fishery has been subject to a system of total allowable catches and fishing quotas since 2015. This study provides insights into the economic dynamics of the small pelagic fishery, informing decision‐making and potential strategies to enhance the sector's performance and overall economic impact.

Toxic metal and trace element levels in the ocean are increasing heterogeneously in the world, which is why it is important to assess their concentrations in organisms of fishing interest. The study of metal concentrations in different fishing grounds is of vital importance for nutritional control. In this study, two fishing grounds have been studied, in the Canary Islands and in Portugal, in each area 50 muscle samples have been taken from each of the studied species, Scomber colias, Sardina pilchardus, and Trachurus species from the Canary Islands (T. picturatus) and Portuguese (T. trachurus). The concentrations of Cd, Pb, Cr, Cu, V and Zn have been analyzed in mg / kg. Cd and Pb concentrations are higher in the species from the Canary Islands and may be linked to the African upwelling inputs, which greatly influence the metal concentrations of the species. The species with the highest concentration of metals and trace elements are influenced by the anthropogenic action of coastal pollution and the natural action of African upwelling and Saharan dust. The Cd and Pb concentrations determined in the muscle tissue of S. colias, T. picturatus, T. trachurus and S. pilchardus are below the maximum permitted limits set by the current legislation, and are, therefore, suitable for human consumption. But supporting very little nutritional percentage of the elements studied. ; En prensa