Nordmøre Grid Trial in Large Prawn Senegalese Fishery: Interest to Reduce By-catch not Evidenced

• DOI: 10.13189/ujar.2018.060601
• Publication Date: 2018-11-08T08:41:16Z
• Authors: Ndiaga Thiam; Fambaye Ngom Sow; Massal Fall; Yoland Plourde; Modou Thiaw; Moustapha Dème; Mor Sylla; Babacar Faye
• Keywords: 0106 biological sciences; 14. Life underwater; 01 natural sciences

Demersal shrimp fisheries, which are not very selective, generate significant discards and / or bycatch, generally composed of crustaceans, fish and molluscs of different size classes. As part of the implementation of the management plan for the deepwater shrimp Parapenaeus longirostris in Senegal, selectivity tests of the Nordmore device were conducted. Thus, three Nordmore grids characterized by different spacings between the bars (24, 28 and 30 mm) were tested on the experimental trawl in the Senegalese Economic Zone. Regardless of spacing, the Nordmore Grid completely removed large individuals from several species of commercial interest (John dory and Bearded brotula) or not (rays, sharks, etc.). Gamba shrimp loss analyzes indicate a significant difference (α <0.05) between the three spacer grids 24, 28 and 30 mm. Regardless of the type of grid, the amount of shrimp sorted per minute is larger for the experimental trawl; and this quantity increases with the spacing of the grid. The 30mm grid stands out with percentages of gamba shrimp losses ranging from 3 to 20% with an average of 8%; and a ratio of bycatch / gamba shrimp catch around 2.2 / 1, below the world average for this type of fishery (5/1).