Nile tilapia of Lake Victoria and fishponds in it's basin

Studies on the comparison of feeding habits, growth patterns and condition factor of Nile tilapia from lake Victoria and fish ponds in Tarime district were conducted between January and February 2008. Water samples and fish were collected from both environments using the la MOTTE water sampler and seine nets respectively. Phytoplankton species in water and gut contents were identified and counted. Before degutting, weight and length of each individual fish were determined. Cyanophytes were found to be the most dominant algae in lake and pond water, which suggest that both environments were eutrophic. Growth of fish from both environments was isometric but the condition factor for pond fish was found to be lower compared to that of lake fish and it was attributed to high level of toxin producing algae found in pond water. Dietary components of fish from both environments were dominated by algae that were most abundant in the environment. This indicate that human induced activities which stimulate changes in trophic state of aquatic ecosystems can have great impact on the feeding habit and growth of Nile tilapia.

Autorentext

Is an Assistant Lecturer in the depart. of Biological sciences of the Sokoine University, Tanzania. He is expecting to graduate his master of Marine ecology at the Vrije Universiteit Brussel in 2011. He holds a bachelor of Aquaculture of the Sokoine University. His research interests have been on aquatic ecology. Email: crumisha@msn.com