Contribution to a better knowledge of bycatch of fixed gillnets of shrimps (Farfantepenaeus notialis) in the Casamance estuary in Southern Senegal

International audienceThis study was carried out in Ziguinchor (Senegal) in southern Senegal where the coastal shrimp Farfantepenaeusnotialisis exploited by a small-scale fishery whose activities have been mainly oriented for several years. Data were collected downstream Casamance Estuary from 26 July to 31 August 2016 at two landing sites: from July 26 to August 12 in Boudodyand then from August 16 to 31under the bridge Emile Badiane. During this period, the landings of 61 fishermen were studied. Those fishermenwere selected at random or through contacts established by the Ziguinchor Regional Fisheries and Surveillance Service. Thecollection was carried out three times a week with fishermen returning from fishing between 9 PMand 10 AM.Juvenile fish are the main bycatch of thistype of fishing gear (86.85%), followed by crustaceans (13.13%) and cephalopod molluscs(0.02%). Most ofthese captures (89.54%) are discarded, 10.46% are retained. Some 39 species constitute the bycatch of fixed net used inshrimp fisherydownstream Casamance estuary. Therearefour species regularly found in fishermen's nets, 1 quite frequently, 5 of them are retrieved occasionally and 29 are erratic. Ethmalosa fimbriata, accounting for almost 60.74%of catches, is the main bycatch species found in fixed net. 64% of species caught belong to the category of minor concernsand 10% are labelledas threatened species(vulnerable and endangered). Out of those 39 species, 13 are estuarine of marine origin and 13 are marine estuarineand 21 of them are predatory species of the second trophic level. Bycatchdiscards account for 140 kg. Some species, mainly juvenilefish, discarded by fishermen are salvaged for human and / or animal consumption. Others arekept by fishermen and are eate