Abstract

Preliminary results are provided of a study instituted to analyze the genetic population structure of the Nile perch in Lake Victoria since 2002. 293 individuals from six geographically distinct locations within the lake were analyzed using two polymorphic microsatellite DNA markers. Tests for differentiation with an overallF_ST = 0.03 (P < 0.05) suggested that populations were genetically differentiated, with the closet population pairs Nyaburu-Rubafu and Mirunda-Maboko as the most differentiated populations. There was an extensive gene flow between the populations (Nm = 20.77). The overall gene diversity (0.17) was low.  All the results point to the fact that Nile perch was only recently introduced species in the lake based on a small founder population, which though slow in establishing later exploded to become the most dominant species in the lake. On the whole the two loci indicate some level of differentiation between locations; however, the levels of genetic differentiation shown by the two loci were not enough to define the structure of Nile perch stocks, and assess the level of exchange between locations.  Further work is underway using bigger number of microsatellite markers.

Key words: Nile perch, Lake Victoria, microsatellite DNA, population structure.