Comparative assessment of diet and condition factor of Cyprinus carpio and Oreochromis leucostictus in Lake Naivasha, Kenya
The study compared and assessed the diet and condition factors of two fish species, Oreochromis leucostictus and Cyprinus carpio, in Lake Naivasha. Fish samples were collected monthly using gill nets (35-70 mm mesh size) from July to December 2013. Stomach contents of all the specimens were analysed using the point method. Results indicated that detritus was the most abundant food item in the diet of both O. leucostictus and C. carpio accounting for 50% and 63%, respectively, while benthic macroinvertebrates contributed the least with each fish having 2%. Rooting and digging behaviour of the carp probably led to both C. carpio and O. leucostictus ingesting the suspended detritus as their main source of food with C. carpio outcompeting O. leucostictus due to its prolific nature and better adaptability to benthic conditions. Fulton's condition factor of all the fish samples had values of >1. A comparison of the two fish species showed C. carpio had a condition factor of 1.51 while O. leucostictus had 1.32. The higher condition factor of C. carpio in Lake Naivasha is an indication that the fish have better tissue energy reserves, greater reproductive potential and higher survival rates compared to O. leucostictus with a lower condition factor.
Bonneau J.L. (1999). Ecology of a fish biomanipulation in a Great Plains Reservoir. Dissertation. University of Idaho.
Braga F.M. (1986). Estudo entre o fator de condicao erelaí§í£o peso/comprimento para alguns peixesmarinhos. Revised Brazilian Biology, 46(2): 339-346.
Britton J.R., Boar R.R., Grey J., Foster J., Lugonzo J., Harper D.M. (2007). From introduction to fishery dominance: The initial impact of the invasive carp Cyprinus carpio in Lake Naivasha, Kenya, 1999 to 2006. Journal of Fish Biology, 71: 239-257.
Donkers P.D. (2004). Age, Growth and Maturity of European Carp (Cyprinus carpio) in Lakes Sorell and Crescent. Technical Report No.4 Inland Fisheries Service, Hobart. 18 p.
Edwards T. (1982). Spatial variability of common carp populations in relation to lake morphology and physicochemical parameters in the upper Midwest United States. Ecology of Freshwater Fish, 19: 555-565.
Efitre J., Chapman J., Murie J. (2009). Fish condition in introduced tilapias of Ugandan crater lakes in relation to deforestation and fishing pressure. Environmental Biology of Fish DOI 10.1007/s10641-009-9461-z.
Harper D.M., Mavuti K.M. (2004). Lake Naivasha, Kenya: Ecohydrology to guide the management of a tropical protected area. Ecohydrology and Hydrobiology, 4: 287-305.
Hickley P., Muchiri M., Britton R., Boar R. (2008). Economic Gain versus Ecological Damage from the Introduction of Non-native Freshwater Fish: Case Studies from Kenya. The Open Fish Science Journal, 1: 36-46.
Hynes H.B.N. (1950). The food of freshwater sticklebacks (G. aculentus and P. pungitius) with a review of methods used in studies of the food of fishes. Journal of Animal Ecology, 19: 36-58.
Hyslop E.J. (1980). Stomach content analysis – a review of method and their application. Journal of Fish Biology, 17: 411–429.
LeCren E.D. (1951). The length weight relationship and season cycle in gonad weight and condition in Perch (Perca fluviatilis). Journal of Animal Ecology, 20: 179-219.
Malvestuto S. (1974). The Fishes of Lake Naivasha: Their Biology, Exploitation and Management. Mimeographed report to the Director of Fisheries, Government of Kenya, Nairobi, Kenya. 37 p.
Muchiri S.M., Hickley P. (1991). The fishery of Lake Naivasha, Kenya. In: I.G. Cowx (Ed). Catch Effort Sampling Strategies: Their application in freshwater fisheries management. Fishing News Books, Blackwell Scientific Publications, Oxford. pp: 382-92.
Nathaniel S., Edirisinghe U., Kotelawela S. (1998). Comparison of length-weight relationships and fecundity between pond cultured and reservoir (Victoria) inhabiting common carp (Cyprinus carpio). Tropical Agricultural Research and Extension, 1(1): 61-66.
Njiru M., Ojuok J.E., Okeyo-Owuor J.B., Muchiri M., Ntiba M.J., Cowx I.G. (2006). Some biological aspects and life history strategies of Nile tilapia Oreochromis niloticus (L.) in Lake Victoria, Kenya. African Journal of Ecology, 44: 30-37.
Oyugi D.O., Harper D.M., Ntiba J.M., Kisia S.M., Britton J.R. (2011). Management implications of the response of two tilapiine cichlids to long-term changes in lake level, allodiversity and exploitation in an equatorial lake. Ambio, 40(5): 469-478.
Oyugi D.O, Cucherousset J., Ntiba M.J., Kisia M.S., Harper M.D., Britton, J.R. (2012). Life history traits of an equatorial common carp Cyprinus carpio population in relation to thermal influences on invasive populations. Fisheries Research, 110: 92-97
Oyugi D.O., Mavuti K.M., Aloo P.A., Ojuok J.E., Britton J.R. (2014). Fish habitat suitability and community structure in the equatorial Lake Naivasha, Kenya. Hydrobiologia, 727: 51-63.
Pope K.L., Willis D.W. (1996). Seasonal influences on freshwater fisheries sampling data. Revised Fisheries Science, 4: 57-73.
Siddiqui A.Q. (1977). The Lake Naivasha fishery, Kenya, and its management together with a note on feeding habits of fishes. Conservation Biology, 12: 217-227.
Waithaka E., Mugo J., Obegi B., Keyombe J.L. (2015). Socio-economics of the re-introduced Oreochromis niloticus in Lake Naivasha (Kenya). International Journal of Fisheries and Aquatic Studies, 2(5): 142-146.
Witte F., Van Densen L.T. (1995). Fish Stocks and Fisheries of Lake Victoria. A Handbook for Field Observations. Cardigan, Samara Publishing, Cardigan, UK. 404 p.
Wooton J. (1990). Ecology of teleost fishes. Chapman and Hall, New York. 404 p.
Yongo E., Lwenya C., Abila R. (2007). Socio-economic impacts of fisheries management strategies. Lake Naivasha fisheries recovery and management challenges, 4: 47-58.