Seasonal Variation, Abundance and Condition Factor of Fish Species in Erinle Reservoir

Abstract

Fish species abundance, seasonal variation and condition factor (k) was assessed in this study between October 2012 and September 2013. Samples collected from Erinle reservoir were identified and sorted out into species, the morphometric parameters of each sample were measured using a measuring board graduated in cm and weighed using a Mettler balance (P 1210 model). Fulton’s condition factor (k) was calculated using the equation K=100W/L. Fish species identified were twelve: Alestes macrolepidotus, Chromidotilapia guntheri, Oreochromis niloticus, Sarotherodon galilaeus, Tilapia mariae, Tilapia zillii, Clarias gariepinus, Chrysichthys auratus, Hepsetus odoe, Mormyrus rume, Marcusenius senegalensis and Schilbe mystus. The species belong to seven families from a total of 561 fish samples with varying degree of abundance. S. galilaeus had the highest abundance of 55.08% of the total samples collected while C. gariepinus had the lowest abundance of 0.18% as only one sample was collected during the study period. Abundance of fish species was higher during the dry season than the raining season with 360 and 201 fish samples respectively. A. macrolepidotus, C. gariepinus and M. senegalensis were not observed during the raining season. Mean condition factor (k) showed the reservoir was favourable for all species except C. gariepinus, C. auratus, H. odoe, M. rume and S. mystus as their K-value was <1.0. The study concluded that Erinle reservoir can support fisheries provided anthropogenic influence is properly monitored and regulated by relevant authorities.