Investigation of biological condition of fish species in lower Ogun River wetlands, Lagos, Nigeria

Abstract

The study was carried out to investigate the biological condition of fish species in lower Ogun River wetlands. A total of 175 individual fish belonging to 10 species were collected from artisanal fishermen usingdifferent types of fishing gears. Two biological indices; condition factor “K” and growth exponent “b” obtained from length-weight relationship were used to determine the biological condition of the fishes. The conditionfactor (K) recorded during the study ranged between 0.55 in Liza grandisquamis and 5.61 in Oreochromis niloticus. The growth exponent (b) ranged from 1.48 in Penaus notialis to 5.67 in Gymnarchus niloticus. Theregression coefficient of determination was significant for some of the fish with highest value of R2=0.98 for Sardinella madarensis. The study showed that most of the fish species in the study area are in poor biologicalcondition and exhibit allometric growth.Keywords: Allometric growth, condition factor, growth exponent, length-weight relationship.