Hypoxia Tolerance of the Mormyrid Petrocephalus catostoma: Implications for Persistence in Swamp Refugia

changes in fish faunal structure and diversity. Though catches of many species had declined by the 1960s due to overexploitation (Kudhongania et al., 1992), the dramatic increase in Nile perch in the 1980s in Lake Victoria was followed by a drastic decline in the populations of several indigenous species (Kaufman, 1992). Most notable has been the disappearance of over 50% of the endemic haplochromine cichlids from Lake Victoria (Kaufman, 1992; Kaufman et al., 1997). However, many indigenous noncichlids, some of which were important in the pre-Nile perch fishery, have also declined or disappeared (Kaufman, 1992; Kudhongania et al., 1992). Similar trends have been observed in other