Experimental Hybridization between catfishes of the families clariidae and pangasidae in Thailand

Abstract

Hybrids between the clariid species Clarias macrochephalus and C. batrachus and the pangasiid species Pangasius sutchi were obtained by horemone injection of brood stock and artificial fertilization. Pure paren tal crosses as well as all possible hybrid combinations were obtained. Fertility, hatchability, and post-yolk absorption survival was high (66-99%) in all pure parental crosses and in all crosses between the two species of Clarias. In corsses between Clarias and Pangasius fertilization was also very hith (68-97%) but hatchability varied from 11 to 23% and post-yolk absorption survival from 0% in Pangasius ♂x Clarias batrachus ♀ to about 50% in Pangasius sutchi ♂x Clarias batrachus ♀ to about 50% in Pangasius sutchi ♂x Clarias macrochephalus ♀. The longestlived hybrids of Pangasius and Clarias were those of Pangasius sutchi ♂x Clarius macrocephalus ♀ which survived until the experiment was prematurely terminated due to poor water quality caused by overfeeding after 4½ months, at which point they has grown to the lengths of 8-14 cm. The hybrids comprised four morphotypes, two relatively Pangasius-like, and two relatively Clarias-like, but all were markedly different from the parental species.