HYBRIDIZATION BETWEEN CLARIAS GARIEPINUS (BURCHELL 1822) AND HETEROBRANCHUS BIDORSALIS (GEOFFROY SAINT HILAIRE, 1809)

Résumé

This study was carried to produce hybrids between crosses of Clariid catfish species of Clariasgariepinus and Heterobranchusbidorsalis for stock improvement. Fertility data revealed significant difference (p<0.05) between the hybrid cross ♀C. gariepinus ♂H. bidorsalis (88.00±1.00%) compared to its reciprocal ♀H. bidorsalis ♂C. gariepinus (71.67±10.41%). The reciprocal ♀H. bidorsalis ♂C. gariepinus recorded the highest deformity (11.67±3.06%) that was significantly different (p<0.05) from the rest of the crosses. Equal sex ratio in the hybrids compared with the two parent species was recorded. Specific growth rate (SGR) of the fish species revealed highest significant difference (p<0.05) in the hybrid ♀C. gariepinus ♂H. bidorsalis (2.64±0.09%), followed by the cross of ♀C. gariepinus ♂ C. gariepinus (1.91±0.02%) while there were no significant differences (p>0.05) between the reciprocal hybrid ♀H. bidorsalis ♂C. gariepinus (2.20±0.57%)and♀H. bidorsalis ♂H. bidorsalis (2.19±0.19%). The SGR analysis proved that the crosses ♀C. gariepinus ♂C. gariepinus had slow growth performance compared to its hybrid ♀C. gariepinus ♂H. bidorsalis. Critical evaluation based on survival and specific growth performance showed superiority of the hybrid ♀C. gariepinus ♂H. bidorsalis. The least survival in reciprocal hybrid ♀H. bidorsalis ♂C. gariepinus (27.33%) can be explained from significant deformity (11.67%) recorded due to maternal effects. Hence, the hybrid ♀C. gariepinus ♂H. bidorsalis performed better in the SGR and survival.