Population characteristics of Schilbe mystus (Linne, 1758), from two different habitats: Asejire and Oyan Lakes Southwestern Nigeria

Abstract

The population variability of Schilbe mystus in Asejire and Oyan Lakes located in Osun and Ogun states respectively is studied for the first time and it would serve as a reference for future sustainable fisheries management in various environments. Specimens of African butter catfish Schilbe mystus were caught from Asejire and Oyan lakes and ten morphometric and six meristic features were investigated and used to evaluate the degree of variation among the populations. The morphological characters of fresh specimens of Schilbe mystus collected from Oyan and Asejire Lakes showed differences in the meristic and morphometric characteristics of the two populations but these were not statistically significant (p>0.05; t-test) except right gill raker count. The mean values for all body measurement ratio were higher for specimens from the Oyan Lake than Asejire Lake, except for pectoral fin length/standard length and anal fin length/standard length ratios, however, they were not significantly different (p<0.05). The two populations are not racially distinct due to close similarities between meristic and morphometric characters. Differences observed in the right gill raker counts may be attributed to environmentally induced changes rather than by genetic properties. © 2011 Academic Journals Inc.