Seasonal variation in the length – weight relationships and condition factor of Gymnarchus niloticus Cuvier, 1829 in Lekki lagoon, Lagos state, Nigeria

Abstract

Length-weight relationship (LWR) and Condition factor (K) of Gymnarchus niloticus from Lekki Lagoon were studied for 24 months to provide useful information for the sustainable development of Gymnarchus niloticus in Lekki lagoon. Samples of G. niloticus caught from the lagoon were obtained from fishers on a bimonthly basis for 24 months. Length – weight data were analyzed and Length – weight relationship graphs were plotted for the dry and wet seasons of the sampling years. The b values in the LWR (W=aLb) varied between 2.56 – 2.60 for the dry seasons and 2.51 – 2.62 for the wet seasons revealing that the somatic growth of G. niloticus at Lekki lagoon had negative allometry. The average condition factor (K) were found to be 0.7113 ± 0.3485 for dry seasons and 0.7047 ± 0.5069 for wet seasons of the sampling period. There was a strong positive correlation (r = 0.99) between the length and weight of fish specimen examined while the Coefficient of determination (R2) varied between 0.9822 – 0.9976 and 0.9951 – 0.9970 for both dry and wet seasons respectively. It was concluded that the data generated will form a baseline tool for effective fisheries management and sustainable exploitation of G. niloticus in Lekki lagoon.