Fecundity and gonadosomatic index of Niger river prawn, Macrobrachium felicinum in the lower Taylor Creek, Niger Delta, Nigeria

Abstract

The fecundity and Gonadosomatic index of M. felicinum was studied between June 2008 and May 2010 in the lower Taylor Creek, Niger Delta, Nigeria. The sex ratios showed that M. felicinum deviated significantly from the ratio 1:1 and females dominated (X² = 411.20, df = 1, P < 0.001). Fifty percent of the female populations attained sexual maturity at size class 4.5 – 5.0 cm total length. The highest Gonadosomatic Index (GSI) for M. felicinum was attained in October 2008 while the lowest values were recorded in November 2008 and 2009 (P < 0.001). There were no monthly and seasonal variations in the GSI means (P > 0.05). However, there were significant differences in the GSI values of the size classes (P < 0.05). The overall fecundity of M. felicinum ranged from 205 eggs (Total length, TL = 3.70 cm) to 8501 eggs (TL = 5.50 cm) with a mean of 2617 ± 207 eggs (P < 0.001). Relative fecundity ranged from 43 to 1546 eggs/cm or 155 to 3847 eggs/g with overall means (± S.E) of 514 ± 37 eggs/cm or 1652 ± 102 eggs/g. The correlations of fecundity – total length, fecundity – gonad weight and fecundity – body weight relationships were positive and gonad weight gave the best predictive values.