Resource-consumer relationships in Lake Victoria were investigated by use of stable isotope data. δ13C and δ15N signatures were determined for organisms at a deep (22 m) and a littoral (5 m) site in the Napoleon Gulf near Jinja, Uganda. Results suggest that two food chains operate at the deep site, one leading from a shrimp (Caridina nilotica) to juvenile Nile perch (Lates niloticus), the second leading from zooplankton (copepods and cladocerans) to a cyprinid (Rastrineobola argentea) and lake flies (Chaoborus). Isotopic evidence suggests that shrimp eat suspended particulates and benthos, not crustacean zooplankton or water hyacinth (Eichhornia crassipes). Resource-consumer relationships revealed in this study have implications for understanding future yields of the economically important Nile perch fishery.
Bibliographical noteFunding Information:
We thank F.W.B. Bugenyi and members of the Fisheries Research Institute in Jinja, Uganda, for support and S. Wasige for assistance with field sampling. Two anonymous reviewers substantially improved the clarity of the manuscript. This research was financially supported in part by the U.S. National Science Foundation International Programs Postdoctoral Fellowship 9403733 to D. K. Branstrator.
- Caridina nilotica
- Lake Victoria
- Lates niloticus
- Stable isotopes