Fecundity and Gonad Development of Atya Gabonensis from Lower River Benue in Northern Nigeria

Abstract

The study investigated the fecundity and egg development of Atya gabonensis from Lower River Benue in Nigeria from May to August 2006. A total of 200 berried females were collected, weighed and the eggs striped and weighed using a top loading electronic balance. The total length of the prawn was also measured using a ruler to the nearest millimeter. The eggs were preserved in Gilson's fluid. The total number of eggs was estimated by the gravimetric method. The egg size was measured using the calibrated eye piece of a binocular microscope. The eggs were classified as immature, developing and ripe with two 'eye' spots called the larva stage. The highest number of eggs observed was 27,700eggs, while the lowest was 950 (mean = 7,227eggs). The egg diameter ranged from 0.02 2mm (0.63 ± 0.10mm). The relationship between fecundity and weight was F = 3.799 + 8.2400W (r = 0.7887), while the one between fecundity and length was F = 5.6067 + 1.9386L (r = 0.7504). There was positive correlation between length, weight and fecundity in A. gabonensis from Lower River Benue. The appearance of eggs in May to August coincides with onset of rain therefore rain is a triggering factor in egg production. A. gabonensis is a serial spawner as the berried females were found to carry eggs in various stages of development.