Abundance, length-weight relationship and condition factors of fish species in Ogbomoso Reservoir, Ogbomoso south-western Nigeria

Abstract

Length-weight relationship (LWR) of 330 fish samples captured from Ogbomoso reservoir was assessed. The parameters a and b of the length-weight relationship of the form W = aLb and condition factor K =100W/L3 are presented for the nine different fish species recorded in this study. The fish species recorded in Ogbomoso reservoir and their families include Chrysichthys nigrodigitatus (Bagridae), Schilble mystus (Schilbeidae), Hepsetus odoe (Hepsetidae), Clarias gariepinus (Clariidae), Parachanna obscura (Channidae), Synodontis gambiensis (Mochokiadae), Heterotis niloticus (Osteoglossidae), Sarotherodon galilaeus (Cichlidae), Oreochromis niloticus (Cichlidae) and Malapterurus electricus (Malapteruridae). The most abundant fish species recorded in Ogbomoso reservoir are O. niloticus, C. nigrodigitatus, S. galilaeus, S. mystus with percentage abundance of 24.8%, 23.9%, 18.2% and 13.3% respectively. The values of b in C. nigrodigitatus, C. gariepinus, P. obscura and O. niloticus showed a positive allometric growth pattern. While H. odoe, S. galilaeus and H. niloticus exhibited a negative allometric growth pattern. The K values significantly (P < 0.01) varied between 0.67 in H. niloticus to 4.66 in O. niloticus.

Key words: Reservoir fisheries, Fish species, length/weight, condition factor.