Reproductive biology and condition factor of the catfish Bagrus docmak (Forsskål) (Pisces: Bagridae) in Lake Chamo, Ethiopia

Abstract

Some aspects of reproductive biology, length-weight relationship and condition factor of 534 (258 males and 276 females) Bagrus docmak (Forsskal) in Lake Chamo were studied from samples taken during February 1995 to February 1996. B . docmak had an extended breeding period from February to August, with peak spawning in May for both sexes, when 76.2% males and 78.3% females had ripe gonads. The main pulse in breeding activity occurred during the rainy months of April and May. The overall sex ratio (male: female) was 1:1.07 which did not deviate significantly from the hypothetical distribution of 1:1 ( x 2 =0.61, p>0.05). However, sex ratio was significantly different from 1:1 in the samples >90 cm fork length (FL) ( x 2 = 10.71, p 2 = 0.75, p 2 = 0.73, p 2 = 0.90, p B . docmak is best expressed by the equation TW= 0.0054FL 3.24 . Monthly Clark’s condition factor (mean +/- SE) ranged from 0.426± 0.011 to 0.489± 0.014 for males and from 0.449± 0.010 to 0.489± 0.012 for females.