Differential growth patterns of Clarias gariepinus, Heterobranchus bidorsalis and Hybrid Heteroclarias fed commercially prepared diets

摘要

Thirty, four week old hatchery bred fingerlings, each of Clarias gariepinus, Heterobranchusbidorsalis and hybrid Heteroclarias (C. gariepinus x H. bidorsalis) were acclimated in a tank ofdimension 1m x 1m x 1m and fed fishmeal for five days. Thereafter they were randomlydistributed in tens into triplicate tanks measuring 1 m x 1m x 1m and fed with commerciallyprepared 0.8–1.2mm Coppens feed for seven weeks, to investigate and compare their growthpatterns. Length and weight were measured weekly and used as growth indices. Condition factor(Kf) of the fishes were also determined. Data collected were subjected to analysis of variance andmeans separated using Duncan’s multiple range test. Apart from weeks 2 and 3 where Kf valuesof above 1 were recorded, fishes generally had Kf values of less than 1 and they were notsignificantly different from each other (P> 0.05). C. gariepinus and H. bidorsalis displayed auniform growth pattern. Growth in hybrid Heteroclarias was not uniform, with fishes measuringabout 8.60 cm and 12.40 cm being recorded at week 7 of the study. However the total standingcrop or itchthyomass in the individual tanks as shown in their mean values were not significantlydifferent (P> 0.05) at the end of the study. Thus farmers can use any of these fishes to stock theirponds and still obtain the same results, as the size of the large ones will compensate for the smallones.