Tropicultura (Jan 2009)
Impact de l'upwelling côtier sur l'abondance et les tailles des marlins bleus, (Makaira nigricans, Lacepède, 1802) capturés au large de la Côte d'Ivoire par les artisans pêcheurs marins
Abstract
Costal Upwelling Impact on the Abundance and Sizes of Blue Marlins (Makaira nigricans, Lacepède, 1802) Captures by Artisans Fishers in the Offing of Ivory Coast. This study concern blue marlins (Makaira nigricans, Lacepede 1802) landed by sea artisan fishers in Abidjan port (Ivory Coast) from February 2006 to January 2007. During the Great Warm Season (GWS) March-April-May, the surface temperature average is 28.61 °C. With a Fishing Effort (FE) of 3,874 canoes; 285 blue marlins have been landed. Their weigh average is 77.70 kg with a Capture by Unit Effort (CPUE) of 5.62 kg. During this warm season, 187 blue marlins (65.61 %) have their sizes between 105 and 200 cm against only 98 (34.39%) which exceeds 200 cm. During the Great Cold Season (GCS) july-august-september, the average temperature is 25.58 °C. With 7,338 canoes (FE) went in sea, 244 fishes have a average weigh of 140.36 kg and a CPUE of 4.23 kg. During this upwelling period, only 43 M. nigricans (17.62%) have their size between 105 and 200 cm, against 201 (82.38%) which measure more than 200 cm. Therefore these two seasons, sizes and weights variance analyze with the Test-t show respectively a p-value highly significant (p- value = 2,255 x 10 -15 < 5%) et (p- value = 7,508 x10 -12 < 5%).
