Environmental Biology of Fishes (2005) 74:247–260 Ó Springer 2005 DOI 10.1007/s10641-005-3190-8 Trophic niche segregation in the Nilotic ichthyofauna of Lake Albert (Uganda, Africa) Linda M. Campbella,d, Sylvester B. Wanderab, Robert J. Thackerc,e, D. George Dixona & Robert E. Heckya aDepartment of Biology, University of Waterloo, 200 University Avenue. Waterloo, Ontario, Canada N2L 3G1 bFisheries Resources Research Institute, P.O. Box 343, Jinja, Uganda cDepartment of Physics and Astronomy, McMaster University, 1280 Main St. W, Hamilton, Ontario, Canada dCurrent address: School of Environmental Studies and Department of Biology, Queen’s University, Kingston, ON, Canada K7L 3N6 (e-mail:
[email protected]) eCurrent address: Department of Physics and Astronomy, Queen’s University, Kingston, ON, Canada K7L 3N6 Received 29 April 2004 Accepted 13 February 2005 Key words: d13C, d15N, food webs, Nile perch, stable isotopes Synopsis Nile perch, Lates niloticus, and Nile tilapia, Oreochromis niloticus, were originally transplanted from Lake Albert in western Uganda to the African Great Lakes, Lake Victoria and Lake Kyoga, where they are partially implicated in reduction of the fish species diversity. Lake Albert is facing multiple environmental changes, including declining fish species diversity, hyper-eutrophication, hypoxia, and reduced fish catches. To examine the role of Nile perch and Nile tilapia in the food web in their native Lake Albert, we estimated their diets using stable nitrogen and carbon isotopes. In Lake Albert, the tilapiine congeners (closely related species), Tilapia zillii, Oreochromis leucostictus, and Sarethorodon galilaeus, and the centropomid Nile perch congener, Lates macrophthalmus, have narrower diet breath in the presence of the native O.