LENGTH-WEIGHT RELATIONSHIP AND FECUNDITY OF PARACHANNA OBSCURA (OPHIOCEPHALIFORMES: CHANNIDAE) IN OVIA RIVER, SOUTHERN NIGERIA

Abstract

The African snakehead, Parachanna obscura (Gunther, 1861) is an important food fish in Nigeria and other West African countries. To provide useful biological data for management, samples were collected monthly between January, 2011 and December, 2011 from Ovia River Nigeria. The Length-weight relationship (LWR), sex composition and fecundity of the fish species were investigated. The fish total lengths ranged from 12.8 to 45.7cm, while the weights ranged from 12.0 to 838.1g. The LWR had a significant correlation and the growth exponent (b) for the species indicates isometric growth. The sex ratio was 1:1.15 (male: female) and was not significantly different (p>0.05) from the expected 1:1 distribution. Absolute fecundity ranged from 346 to 4586 eggs with a mean of 2073±179 eggs. Mean absolute fecundity increased with increasing fish length, fish body weight and ovary weight. The regressions of fecundity on total length, body weight and ovary weight of P. obscura were: Log F = 0.370 + 2.45 logTL (r=0.267; P>0.05), Log F = 1.790 + 0.607 logBW (r = 0.230; P>0.05) and Log F = 1.960 + 1.602 logOW (r = 0.536; P<0.001) respectively. Fecundity-ovary weight gave a better relationship in comparison with fecundity-total length and fecundity-body weight relationships.