Seasonal changes in length-weight relationship and condition factor of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) (Cichlidae) in Lake Naivasha, Kenya

Fisheries Biology Oreochromis niloticus Lake Naivasha

Authors

  • James Last Keyombe
    katalitsa@yahoo.com
    Kenya Marine and Fisheries Research Institute, Turkana Research Station, P.O. Box 205-30500, Lodwar, Kenya.
  • John O. Malala Kenya Marine and Fisheries Research Institute, Turkana Research Station, P.O. Box 205-30500, Lodwar, Kenya.
  • Edna Waithaka Kenya Marine and Fisheries Research Institute, Naivasha Research Station, P.O. Box 837-20117, Naivasha, Kenya.
  • Ruth M. Lewo Nakuru County Fisheries Department, Naivasha Sub-County, P.O. Box 135-20117, Naivasha, Kenya.
  • Benson Ojowi Obwanga Laikipia University, Department of Biological and Biomedical Sciences, P.O. Box 1100-20300, Nyahururu, Kenya.
January 26, 2017

Downloads

The study compared the length-weight relationship and condition factor (K) of Nile tilapia (Oreochromis niloticus) in Lake Naivasha, Kenya, between the wet and dry seasons. Fish samples were collected monthly by gill netting from February to December 2015. A total of 372 samples of O. niloticus were analysed. The b values in the length-weight relationships were observed as 3.077 and 3.366 in the wet and dry seasons, respectively. The values of b exhibited positive allometric growth which were the important indication that the species was growing faster in weight than length. The K values of the fish ranged 1.18-4.1 during the wet season and 0.8-3.0 during the dry season.  All mean monthly K values were found to be greater than 1, the highest being in June (2.33±0.05) and lowest in February (1.31±0.28), an indication of a healthy status and general well-being of the O. niloticus population in Lake Naivasha. The study concluded that seasonal variation has no great influence in the length-weight relationship and condition factor of O. niloticus in Lake Naivasha.