THE EFFECTS OF TILAPIA INTRODUCTIONS IN LAKE LUHONDO, RWANDA

Cyprinid fishes apparently constituted the major part of the original fish fauna in Lake Luhondo, Rwanda, at least until 1934. At that time only three species, all cyprinids, were known from the lake:Barbus neumayeri, a small barbel, very common in the lake (described from the lake as Barbus luhondo) and two larger cyprinid species:Barbus microbarbis and Varicorhinus ruandae. These two large species were probably not very common in the lake. Between 1935 and 1938 some young Tilapia were introduced into Lake Luhondo. Since then and certainly since 1952 the large cyprinids seem to have disappeared completely from the lake. The small Barbus neumayeri has become extremely rare; at present it survives only in some small tributaries of the lake. In the lake itself Tilapia and Haplochromis species are now the dominant fauna. A survey of the available information is given. © 1990 Kluwer Academic Publishers.