International Journal of Agricultural Policy and Research
Vol.6 (11), pp. 189-200, December 2018
Available online at https://www.journalissues.org/IJAPR/
Author(s) retain the copyright of this article. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License.
Original Research Article
Contribution to a better knowledge of bycatch of fixed gillnets of shrimps (Farfantepenaeus notialis) in the Casamance estuary in Southern Senegal
Hamet Diaw Diadhiou*1, Oumar Sadio2, Samba Diallo3 and Constance Agboba4
1Senegalese Agricultural Research Institute (ISRA) / Dakar-Thiaroye Oceanographic Research Center (CRODT), BP 2241 Dakar Senegal.
2Research Institute for Development (IRD), UMR LEMAR 195 (Environmental Sciences Laboratory MARin), LEMAR-IRD, CRODT-ISRA, BP 1386 Dakar, Senegal.
3Fisheries Ecology, Cheikh Anta DIOP University of Dakar Senegal.
4Department of Animal Biology, Cheikh Anta Diop University, Dakar Senegal.
*Corresponding Author Email : hamet_diadhiou(at)yahoo.fr,hametdiadhiou(at)gmail.com
Tel.:+221 77647 33 98
This study was carried out in Ziguinchor (Senegal) in southern Senegal where the coastal shrimp Farfantepenaeus notialis is 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 Boudody and then from August 16 to 31 under the bridge Emile Badiane. During this period, the landings of 61 fishermen were studied. Those fishermen were selected at random or through contacts established by the Ziguinchor Regional Fisheries and Surveillance Service. The collection was carried out three times a week with fishermen returning from fishing between 9 PM and 10 AM. Juvenile fish are the main bycatch of this type of fishing gear (86.85%), followed by crustaceans (13.13%) and cephalopod molluscs (0.02%). Most of these captures (89.54%) are discarded, 10.46% are retained. Some 39 species constitute the bycatch of fixed net used in shrimp fishery downstream Casamance estuary. There are four 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 concerns and 10% are labelled as threatened species (vulnerable and endangered). Out of those 39 species, 13 are estuarine of marine origin and 13 are marine estuarine and 21 of them are predatory species of the second trophic level. Bycatch discards account for 140 kg. Some species, mainly juvenile fish, discarded by fishermen are salvaged for human and / or animal consumption. Others are kept by fishermen and are eaten.
Key words: bycatch - fixed nets - artisanal shrimp fishery - Farfantepenaeus notialis, downstream estuary of Casamance, Senegal