Suchergebnisse

WOS:000485654700032 ; International audience ; Fisheries management is difficult especially in developing countries where there are little or no data available for stock assessment. Here, a simple model based on the length-based Bayesian biomass (LBB) is applied to length frequencies collected on the two sardinella species (Sardinella maderensis and S. aurita) collected in Senegalese waters (2004 to 2014) to diagnose these stocks and to support the development of fishery management options that may improve the livelihoods of artisanal fishermen. Annual mean length of both species of sardinella showed a large variation during the decadal study period. It is assumed that such variations are due to environmental changes. According to our results, based on the current exploitation rate, both sardinella species are overexploited. To reverse these bad stock status, three management indicators were estimated for both sardinella: (i) length at first capture (Total Length (TL); L-c 24 and 27 cm for S. maderensis and S. aurita, respectively); (ii) the length at maximum possible yield per recruit (TL; L-opt 26 and 29 cm for S. maderensis and S. aurita, respectively); and (iii) the optimal length for the first capture (TL; L-c\ₒpt; 25 and 28 cm for S. maderensis and S. aurita, respectively). According to Senegalese maritime fishing code, which sets the small pelagic fish size of the first capture \textgreater= 18 cm, we urge the Senegalese governments to press ahead with much needed reforms of the fishing code. We recommend capturing sardinella at the size L-c\ₒpt to provide a natural safeguard against any recruitment failure related to environmental variability and allow individuals to grow and ensure the long-term survival of populations and thus sustainable fisheries. The results suggest that LBB model could be a tool to assess data-poor fisheries allowing the possibility to include in the analysis several years of length-frequency data with a minimum of prerequisites.

WOS:000485654700032 ; International audience ; Fisheries management is difficult especially in developing countries where there are little or no data available for stock assessment. Here, a simple model based on the length-based Bayesian biomass (LBB) is applied to length frequencies collected on the two sardinella species (Sardinella maderensis and S. aurita) collected in Senegalese waters (2004 to 2014) to diagnose these stocks and to support the development of fishery management options that may improve the livelihoods of artisanal fishermen. Annual mean length of both species of sardinella showed a large variation during the decadal study period. It is assumed that such variations are due to environmental changes. According to our results, based on the current exploitation rate, both sardinella species are overexploited. To reverse these bad stock status, three management indicators were estimated for both sardinella: (i) length at first capture (Total Length (TL); L-c 24 and 27 cm for S. maderensis and S. aurita, respectively); (ii) the length at maximum possible yield per recruit (TL; L-opt 26 and 29 cm for S. maderensis and S. aurita, respectively); and (iii) the optimal length for the first capture (TL; L-c\ₒpt; 25 and 28 cm for S. maderensis and S. aurita, respectively). According to Senegalese maritime fishing code, which sets the small pelagic fish size of the first capture \textgreater= 18 cm, we urge the Senegalese governments to press ahead with much needed reforms of the fishing code. We recommend capturing sardinella at the size L-c\ₒpt to provide a natural safeguard against any recruitment failure related to environmental variability and allow individuals to grow and ensure the long-term survival of populations and thus sustainable fisheries. The results suggest that LBB model could be a tool to assess data-poor fisheries allowing the possibility to include in the analysis several years of length-frequency data with a minimum of prerequisites.

WOS:000485654700032 ; International audience ; Fisheries management is difficult especially in developing countries where there are little or no data available for stock assessment. Here, a simple model based on the length-based Bayesian biomass (LBB) is applied to length frequencies collected on the two sardinella species (Sardinella maderensis and S. aurita) collected in Senegalese waters (2004 to 2014) to diagnose these stocks and to support the development of fishery management options that may improve the livelihoods of artisanal fishermen. Annual mean length of both species of sardinella showed a large variation during the decadal study period. It is assumed that such variations are due to environmental changes. According to our results, based on the current exploitation rate, both sardinella species are overexploited. To reverse these bad stock status, three management indicators were estimated for both sardinella: (i) length at first capture (Total Length (TL); L-c 24 and 27 cm for S. maderensis and S. aurita, respectively); (ii) the length at maximum possible yield per recruit (TL; L-opt 26 and 29 cm for S. maderensis and S. aurita, respectively); and (iii) the optimal length for the first capture (TL; L-c\ₒpt; 25 and 28 cm for S. maderensis and S. aurita, respectively). According to Senegalese maritime fishing code, which sets the small pelagic fish size of the first capture \textgreater= 18 cm, we urge the Senegalese governments to press ahead with much needed reforms of the fishing code. We recommend capturing sardinella at the size L-c\ₒpt to provide a natural safeguard against any recruitment failure related to environmental variability and allow individuals to grow and ensure the long-term survival of populations and thus sustainable fisheries. The results suggest that LBB model could be a tool to assess data-poor fisheries allowing the possibility to include in the analysis several years of length-frequency data with a minimum of prerequisites.

This document contains the 1st management recommendation (MR) invitations submitted to the case studies in the FarFish project. The purpose of these MR invitations is to offer selected operators (resource users) the opportunity to develop MRs in accordance with the responsive fisheries management system (RFMS) approach; following the "first draft general guidelines for making MRs" presented in FarFish deliverable 3.1. The RFMS is a management approach founded on the principles of results-based management (RBM). According to RFMS, the responsibility for fisheries management is partly transferred to the resource users, provided that they meet with necessary requirements set forth by the competent authorities and provide documentation confirming implementation and achievement of specified management objectives. The advantages of such an approach include facilitation of more bottom-up style of management where the actual resource users and other stakeholders are involved, which is likely to increase the sense of ownership of the resource users in the management. Other advantages are for example increased transparency, as well as reduced costs and increased coverage of monitoring, control and surveillance. The MR invitations presented here are for each of the six FarFish case studies, i.e. the EU fleets operating in SW-Atlantic high-seas mixed demersal fishery, the SE-Atlantic high-seas mixed demersal fishery, Cabo Verde SFPA fishery, Senegalese SFPA fishery, Mauritanian SFPA fishery and the Seychelles SFPA fishery. The MR invitations follow up on a pre-invitation dialogues where the basics of the RFMS approach have been introduced. The MR invitations include a short description of what is to be the main focus of the MRs, identification of the main actors and their roles and responsibilities in the process, details on the current status of the fishery and finally the identification of so-called Outcome Targets (OTs) that are specific and measurable performance goals that the MRs are to meet. It should be taken into ...

International audience ; Bioaccumulation of toxic metal elements including mercury (Hg) can be highly variable in marine fish species. Metal concentration is influenced by various species-specific physiological and ecological traits, including individual diet composition and foraging habitat. The impact of trophic ecology and habitat preference on Hg accumulation was analyzed through total Hg concentration and stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the muscle of 132 fish belonging to 23 different species from the Senegalese coast (West Africa), where the marine ecosystem is submitted to nutrient inputs from various sources such as upwelling or rivers. Species-specific ecological traits were first investigated and results showed that vertical (i.e. water column distribution) and horizontal habitat (i.e. distance from the coast) led to differential Hg accumulation among species. Coastal and demersal fish were more contaminated than offshore and pelagic species. Individual characteristics therefore revealed an increase of Hg concentration in muscle that paralleled trophic level for some locations. Considering all individuals, the main carbon source was significantly correlated with Hg concentration, again revealing a higher accumulation for fish foraging in nearshore and benthic habitats. The large intraspecific variability observed in stable isotope signatures highlights the need to conduct ecotoxicological studies at the individual level to ensure a thorough understanding of mechanisms driving metal accumulation in marine fish. For individuals from a same species and site, Hg variation was mainly explained by fish length, in accordance with the bioaccumulation of Hg over time. Finally, Hg concentrations in fish muscle are discussed regarding their human health impact. No individual exceeded the current maximum acceptable limit for seafood consumption set by both the European Union and the Food and Agriculture Organization of the United Nations. However, overconsumption of some coastal ...

International audience ; Bioaccumulation of toxic metal elements including mercury (Hg) can be highly variable in marine fish species. Metal concentration is influenced by various species-specific physiological and ecological traits, including individual diet composition and foraging habitat. The impact of trophic ecology and habitat preference on Hg accumulation was analyzed through total Hg concentration and stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the muscle of 132 fish belonging to 23 different species from the Senegalese coast (West Africa), where the marine ecosystem is submitted to nutrient inputs from various sources such as upwelling or rivers. Species-specific ecological traits were first investigated and results showed that vertical (i.e. water column distribution) and horizontal habitat (i.e. distance from the coast) led to differential Hg accumulation among species. Coastal and demersal fish were more contaminated than offshore and pelagic species. Individual characteristics therefore revealed an increase of Hg concentration in muscle that paralleled trophic level for some locations. Considering all individuals, the main carbon source was significantly correlated with Hg concentration, again revealing a higher accumulation for fish foraging in nearshore and benthic habitats. The large intraspecific variability observed in stable isotope signatures highlights the need to conduct ecotoxicological studies at the individual level to ensure a thorough understanding of mechanisms driving metal accumulation in marine fish. For individuals from a same species and site, Hg variation was mainly explained by fish length, in accordance with the bioaccumulation of Hg over time. Finally, Hg concentrations in fish muscle are discussed regarding their human health impact. No individual exceeded the current maximum acceptable limit for seafood consumption set by both the European Union and the Food and Agriculture Organization of the United Nations. However, overconsumption of some coastal ...

International audience ; Bioaccumulation of toxic metal elements including mercury (Hg) can be highly variable in marine fish species. Metal concentration is influenced by various species-specific physiological and ecological traits, including individual diet composition and foraging habitat. The impact of trophic ecology and habitat preference on Hg accumulation was analyzed through total Hg concentration and stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the muscle of 132 fish belonging to 23 different species from the Senegalese coast (West Africa), where the marine ecosystem is submitted to nutrient inputs from various sources such as upwelling or rivers. Species-specific ecological traits were first investigated and results showed that vertical (i.e. water column distribution) and horizontal habitat (i.e. distance from the coast) led to differential Hg accumulation among species. Coastal and demersal fish were more contaminated than offshore and pelagic species. Individual characteristics therefore revealed an increase of Hg concentration in muscle that paralleled trophic level for some locations. Considering all individuals, the main carbon source was significantly correlated with Hg concentration, again revealing a higher accumulation for fish foraging in nearshore and benthic habitats. The large intraspecific variability observed in stable isotope signatures highlights the need to conduct ecotoxicological studies at the individual level to ensure a thorough understanding of mechanisms driving metal accumulation in marine fish. For individuals from a same species and site, Hg variation was mainly explained by fish length, in accordance with the bioaccumulation of Hg over time. Finally, Hg concentrations in fish muscle are discussed regarding their human health impact. No individual exceeded the current maximum acceptable limit for seafood consumption set by both the European Union and the Food and Agriculture Organization of the United Nations. However, overconsumption of some coastal ...

International audience ; Bioaccumulation of toxic metal elements including mercury (Hg) can be highly variable in marine fish species. Metal concentration is influenced by various species-specific physiological and ecological traits, including individual diet composition and foraging habitat. The impact of trophic ecology and habitat preference on Hg accumulation was analyzed through total Hg concentration and stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the muscle of 132 fish belonging to 23 different species from the Senegalese coast (West Africa), where the marine ecosystem is submitted to nutrient inputs from various sources such as upwelling or rivers. Species-specific ecological traits were first investigated and results showed that vertical (i.e. water column distribution) and horizontal habitat (i.e. distance from the coast) led to differential Hg accumulation among species. Coastal and demersal fish were more contaminated than offshore and pelagic species. Individual characteristics therefore revealed an increase of Hg concentration in muscle that paralleled trophic level for some locations. Considering all individuals, the main carbon source was significantly correlated with Hg concentration, again revealing a higher accumulation for fish foraging in nearshore and benthic habitats. The large intraspecific variability observed in stable isotope signatures highlights the need to conduct ecotoxicological studies at the individual level to ensure a thorough understanding of mechanisms driving metal accumulation in marine fish. For individuals from a same species and site, Hg variation was mainly explained by fish length, in accordance with the bioaccumulation of Hg over time. Finally, Hg concentrations in fish muscle are discussed regarding their human health impact. No individual exceeded the current maximum acceptable limit for seafood consumption set by both the European Union and the Food and Agriculture Organization of the United Nations. However, overconsumption of some coastal ...

International audience ; Bioaccumulation of toxic metal elements including mercury (Hg) can be highly variable in marine fish species. Metal concentration is influenced by various species-specific physiological and ecological traits, including individual diet composition and foraging habitat. The impact of trophic ecology and habitat preference on Hg accumulation was analyzed through total Hg concentration and stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the muscle of 132 fish belonging to 23 different species from the Senegalese coast (West Africa), where the marine ecosystem is submitted to nutrient inputs from various sources such as upwelling or rivers. Species-specific ecological traits were first investigated and results showed that vertical (i.e. water column distribution) and horizontal habitat (i.e. distance from the coast) led to differential Hg accumulation among species. Coastal and demersal fish were more contaminated than offshore and pelagic species. Individual characteristics therefore revealed an increase of Hg concentration in muscle that paralleled trophic level for some locations. Considering all individuals, the main carbon source was significantly correlated with Hg concentration, again revealing a higher accumulation for fish foraging in nearshore and benthic habitats. The large intraspecific variability observed in stable isotope signatures highlights the need to conduct ecotoxicological studies at the individual level to ensure a thorough understanding of mechanisms driving metal accumulation in marine fish. For individuals from a same species and site, Hg variation was mainly explained by fish length, in accordance with the bioaccumulation of Hg over time. Finally, Hg concentrations in fish muscle are discussed regarding their human health impact. No individual exceeded the current maximum acceptable limit for seafood consumption set by both the European Union and the Food and Agriculture Organization of the United Nations. However, overconsumption of some coastal ...

Task 2.3 of work package 2 (Advancing biological knowledge and evaluation of current stock assessment models) focuses on the compilation of biological, ecological and fisheries dependent and fisheries independent data that is required for other FarFish WPs. During the first year of FarFish, some modifications in the objectives occurred, resulting in changes in the species. For example, in the Cape Verde and Seychelles CSs, the focus is now on by-catch species that are not assessed by the Regional Management Fisheries Organizations (RMFO): the International Commission for the Conservation of Atlantic Tunas (ICCAT) and the Indian Ocean Tuna Commission (IOTC). Lists of species for each CS have now been drawn up, sources of data identified, contacts have been made with RMFOs and DG MARE, and data is being compiled. Data compilation has been largely driven by the FarFish Data Base (FFDB) template developed in WP 6 (see deliverables D6.1 and D6.4). On the other hand, other data required for visualization purposes, especially time series, is also being compiled or requested. A formal data request is being prepared for DG MARE, while coastal state CS participants will be requested to provide data for the FFDB. Talks are also ongoing with RFMOs, especially CECAF, regarding data acquisition and how FarFish can contribute or add value to assessment and management. Actions that need to be taken by Task 2.3 participants include the provision of data and uploading of data to the FFDB. Task 2.3 is ongoing (Report on biological and ecological data in FFDB pilot version 2, due in Month 26 (July 31, 2019). ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 727891.

This report contains basic description of the six case studies (CS) in the FarFish project. Four of the CS have Sustainable Fisheries Partnership Agreements (SFPA) with the EU and two are within international waters. The CS cover the Cape Verde tuna fishery (SFPA), the Senegal tuna and hake fishery (SFPA), the Mauritanian mixed fishery (SFPA), Seychelles tuna fishery (SFPA), the high-seas mixed fishery in the South West Atlantic (FAO Major Fishing Area 41) and the mixed fishery in the international waters of South East Atlantic (FAO Area 47). The information presented is primarily based on a review of the available literature and the data that will feed other FarFish work packages (WPs). This case study characterizations, which will be updated as the project progresses, includes descriptions of geography, oceanography, ecosystem characteristics, fisheries activity and production in the area. It also includes description of the existing management procedures and overall their objectives, stock assessment methods used; as well as identification of the main relevant authorities, operators and other stakeholders. The governance within the fisheries is also discussed, as well as issues related to compliance and transparency. The main findings in the evaluation of the SFPA or the high-seas fishery is presented; and the supply-/value chain is studied. The CS characterizations also include overviews of how FarFish will address the gaps and challenges identified, as well as links to the most relevant literature and data. The case studies cover a range of fisheries of different complexity, from largely single (or a few) tuna fisheries to multi-species demersal fisheries. The management regimes do also range from essentially no management in the case of the high-seas mixed fishery in the South West Atlantic (FAO Major Fishing Area 41), to management at the national and Regional Fisheries Management Organisation (RFMO) levels. While each case study is in general unique, they all face similar problems and challenges. These ...