Impact of Oreochromis mossambicus × O. niloticus (Pisces: Cichlidae) hybridization on population reproductive potential and long-term influence on a reservoir fishery.
Introgressive hybridization of 2 tilapia species (Oreochromis mossambicus and O. niloticus) in 3 Sri Lankan reservoirs was studied. An imbalance in the sex ratio with a dominance of males was found. The estimated fecundity for 20-cm fish, calculated from previous estimates of the number of eggs recovered from the ovaries and the total length of captured fish, indicated that there was a decline in fecundity in the hybrids. The importance of the results for the management of reservoir fisheries in Asia is discussed.