Journal of Fisheries and Life Sciences

Author(s): Olapade Olufemi, J Mawundu Sellu and Amidu Mansaray

Abstract: The well-being of fish in the environment where they grow is evaluated often with the length-weight relationship and condition factor. In this study, the length-weight relationships and condition factor ‘K’ of 46 specimens of Lates niloticus (Linnaeus, 1762) and 92 specimens of Papyrocranus (=Notopterus) afer (Günther, 1868) were studied for 6 months (August, 2016 - February, 2017). The formula LogW = - 1.5089 + 2.6634TL and LogW =-1.7988+ 2.7005LogTL were used to determine length and weight of the fish samples. A positive ‘r²â€™ of 0.7904 exists between the length and weight of Lates niloticus while that for Notopterus afer was 0.6995.The ‘b’ value of L. niloticus was 2.66 while that of N. afer was 2.70 and were not significantly different from 3 (P > 0.05). The ‘b’ value for the two species showed negative allometric growth. L. niloticus exhibited positive allometric growth in weight (b>3) in the dry and rainy season while for the length it was negative allometric growth (b<3). A similar result was obtained for N. afer in both dry and rainy season. Condition factor (K) of 0.575 and 0.520 was recorded for N. afer during the rainy and dry season while K values of 1.23 and 1.03 were recorded for L. niloticus in the dry and rainy seasons respectively. In both seasons for the species, growth appeared to correlate positively with condition factor (K). All the water quality parameters monitored excepting turbidity fell within recommended range for the growth and survival of tropical fishes.