The Fecundity And Egg Sizes In Tilapia zillii From Lekki Lagoon, Nigeria
Tilapia zillii were collected from the catches of fishermen operating on Lekki Lagoon between February and November 2000. The length, weight, sex and stages of gonad development were recorded and fecundity determined by the wet weight method. Egg size was measured under a binocular microscope with the aid of a standardised calibrated eyepiece. Chi-square test did not show any significant difference between the observed and the expected female:male ratio of 1:1.The condition factor was 1.76 ±0.21. The gonadosomatic index was 6.11 ±1.95. Absolute and relative fecundities were 2,102.7 ±93.90 and 23.67 ±0.89 eggs/g respectively. The maximum mean egg size recorded was 2.29 mm. The apparent low fecundity and large egg observed in this population though differed from those recorded for the great lakes of East Africa, was, however, found to be consistent with life history theory proposed by Stearns.
Keywords: gonadosomatic index, fecundity, Tilapia zillii, Lekki Lagoon
Nigerian Journal of Fisheries Vol. 5 (1) 2008: pp. 38-48