Genetics of size variation in the juvenile African catfish. Heterobranchus longifilis (Clariidae: Pisces) present in west African lentic systems.

摘要

This experiment was aimed at investigating the cause of shooting (size variation) among juvenile Heterobranchus longifilis and the subsequent evaluation of the intraspecific variation in body size, the knowledge of which is a prerequisite for establishing breeding programmes for this catfish species. In total 10 families of 5 populations were scheduled for evaluation on the basis of full-sib family comparison. The near similarity in coefficient of variation of families in the F1 and F2 generationsis suggestive of the role of heredity in shooting among juveniles. Survival at day 0 (range from 86% to 99%) and was higher in the first generation than in the second generation (range 56% to 95%). Comparative growth profiles of the F1 and F2 generationsshowed no significant differences. No correlation existed between body weight and survival (r = 0.0217) and brood size and survival (r = 0.068); but a high correlation was observed between body weight and length at day 90 and brood size (r = 0.721). Thestandard deviations of all traits analysed indicated a distinct variability. The aquaculture implications of these findings are discussed.