Genetic variation of Taeniolethrinops praeorbitalis (Chisawasawa) in the central and southern Lake Malawi

Abstract

Lethrinops spp flock is one of the major commercially important fish species exploited in Lake Malawi. It contributes a large portion of inshore and deep-water catches yet little is known about its population genetics, which could provide information for making management decisions for sustainable exploitation and conservation. This study was carried out to determine the genetic diversity and population structure of Taeniolethrinops praeorbitalis populations in traditional fisheries of central and southern Lake Malawi. A total of 10 populations of 40 individuals each were analyzed at six microsatellite DNA loci. The populations were not in Hardy-Weinberg equilibrium possibly due to inter-deme mixing leading to Wuhland effect. This is supported by inter-deme migration of more than seven individuals per generation as determined by Slatkin's private allele method. Mean FST value was 0.15. Allelic diversity as a measure of genetic variation was not significantly different between populations in Mangochi district and those in Nkhota-kota district (p> 0.05) despite high fishing pressure in the former. The genetic relationships among the populations appear to be less influenced by geographical distance, normalized Mantel's statistic Z = 0.06, implying that T. praeorbitalis does not occur in discrete populations in Lake Malawi.



UNISWA Jnl of Agric Vol 10 2001: pp 30-39