Genetic Characterization and Early Life Culture Performance Evaluation of Four Ghanaian Populations of Tilapia Guineensis (Pisces; Cichlidae)

Abstract

Genetic characteristics of four populations of the cichlid Tilapia guineensis were studied using allozyme (starch gel) electrophoresis and early life culture performance characterization to generate information on genetic structure and characteristics of major culture performance traits during early life of the species. Samples of the fish populations were collected from three freshwater reservoirs: (i) the Volta reservoir at Kpong, (ii) the Okye-Aminsa reservoir at Akotogua and (iii) the Ayensu reservoir at Okyereko; and a coastal open lagoon of the Volta system at Aglorkpovie. Observed heterozygosity (Ho) and polymorphism (P) of allozymes as indices of genetic diversity were relatively low in Akotogua (Ho = 0.077; P = 0.077) and Aglorkpovie (Ho = 0.077; P = 0.077) populations compared to those of Kpong (Ho = 0.308; P = 0.089) and Okyereko (Ho = 0.462; P = 0.087) populations. Early life culture performance characteristics of populations evaluated over 84 days showed significantly higher final mean length, weight gain and condition factor in Akotogua populations compared to growth characteristics of Aglorkpovie and Kpong populations. Results suggest that heterozygosity and polymorphism might be important in determining culture performance traits. Additionally, high genetic diversity did not confer high culture performance characteristics on the early life of the fish. The biochemical genetic structure and growth characteristics observed in Akotogua population identify it as a population with a potentially better early life culture performance that could be used by culturists for improvement of T. guineensis in aquaculture.