SOME ASPECTS OF REPRODUCTIVE BIOLOGY OF AFRICAN SNAKEHEAD (Parachanna obscura, Gunther, 1861) DURING DRY SEASON IN RIVER OLUWA, AGBABU ONDO STATE, NIGERIA

Abstract

Some aspects of the reproductive biology of African Snakehead Parachanna obscura (Gunther, 1861) obtained live from catches of artisanal fishermen from Oluwa River at Agbabu fish landing site, South West Nigeria was studied between December 2010 to February 2011 and September to November 2011. A total of 155 specimens were collected during the period of study consisting of 110 male and 45 female specimens. The female fish has a total Length ranging between 20.0 cm and 34.0 cm with a mean of 25.69±4.34, the male fish has a total length ranging between 22.48 cm and 45.00 cm with a mean of 29.14± 5.24; The female fish has a weight ranging between 105.5 g and 450.0 g with a mean of 188.60±78.83, the male fish has a weight ranging between 105.0 g and 910 g with a mean of 256.55±167.22.The Length-Weight Relationship indicated positive isometric growth for male specimen Log W= -2.589 +3.373LogL and positive allometric growth for female specimen and Log W= -0.3831+1.873LogL. Fecundity estimates for female Parachanna obscura specimen ranged from 400-8000 eggs. Analysis shows that there was a high positive relationship between fecundity and gonadal weight. The sex ratio revealed a preponderance of male specimen over females in the dry period with female to male sex ratio of 1:2.4. The mean condition factors of 1.11 and 0.91 for female and male Parachanna obscura specimens respectively revealed that condition factor was better in the female than in the male specimens. Parachanna obscura did not show any distinct pattern of breeding during the period of sample collection. Female Parachanna obscura exhibited higher GSI than the male with the highest mean GSI recorded in the month of December 2010 and followed by the month of October, 2011.