Effects of Water Pollution on the Condition Factor, Mortality, Exploitation Ratio and Catch per Unit Effort of ＂Lagocephalus laevigatus＂ in Koluama Area, Niger Delta Area, Nigeria

E. N. Ogamba ； J. F. N. Abowei

《Research Journal of Environmental and Earth Sciences》 4卷11期 (2012/11) Pp. 945-952

並列摘要

Effects of water pollution on the condition factor, mortality, exploitation ratio and catch per unit effort of ＂Lagocephalus laevigatus＂ in Koluama Area, Niger Delta Area, Nigeria was investigated from April 2012 to May 2012; following an oil blow out in the area. To show the impact of the spill on the environment, catch rates are seasonally dependent and vary between 15-120 kg/day. About 120 wooden canoes were sighted in the communities studied. The canoes are basically in two categories namely, small sized boats of less than 5 m length and mediumsized ones ranging between 5 and 7 m long. There was no temporal variation in the condition of the fish with condition index value ranging from 0.86-1.00 and condition factor value of 0.98. The K value of 0.98 estimated from this study shows that ＂Lagocephalus laevigatus＂ from the study area was in extremely poor condition. Total mortality (Z) value was 1.5 yrG1. Natural Mortality (M) value was 0.97; Fishing mortality (F) value was 0.52. Value for the rate of exploitation was 0.35 with corresponding percentage value of 35%. The result shows that ＂Lagocephalus laevigatus＂ with an exploitation rate of 0.35 is below the optimal value for sustainable yield, for the exploitation of the fishery. These populations therefore stand the risk of under exploitation if urgent measures are not taken to develop the fishery.

並列關鍵字

Koluama area ； ＂Lagocephalus laevigatus＂ ； Niger delta ； Nigeria ； population parameters ； water pollution effects