Growth, Mortality, and Longevity of Tilapia guineensis (Bleeker, 1852) in Tropical Man-Made Lake, Southwestern Nigeria

Document Type : Original Article


Hydrobiology and Fisheries Unit, Department of Zoology, University of Ibadan, Oyo State, Nigeria


Background: Fisheries resources are being depleted due to over-exploitation and inadequate information for planning and management; therefore, data on growth pattern, mortality, and exploitation rates of fisheries resources are essential for effective management and sustainable exploitation.
Method: Growth parameters, mortality rates, and longevity of the Guinean tilapia, Tilapia guineensis, (Bleeker, 1852) in Asejire Lake were obtained from length composition data from January, 2013 to December, 2013.
Results: The von Bertalanfy growth function estimates were: L∞ = 30.98 cm Total length, K = 0.37 year-1 and t0 = -0.441. Total mortality rate (Z)was 1.19 year-1, natural mortality rate (M) was calculated as 0.92 year-1 , fishing mortality rate (F) obtained was 0.27 year-1, and the exploitation rate (E) was 0.23. Growth performance index (ø) computed as 2.55.
Conclusion: This result indicates low growth rate. The stock was not overexploited since exploitation rate was less than the optimal exploitation rate(0.5).