Induction of Triploidy by Cold Shock in Indian catfish, Heteropneustes fossilis (Bloch)

Abstract

Indian catfish (Heteropneustes fossilis, Heteropneustidae) is a highly nutritious fish with a comparatively slow growth rate compared to other popular Indian fishes. Triploids are expected to show higher growth potential due to sterility and reduced gonadal develop­ment. In an attempt to improve growth potential in this catfish, activated eggs were sub­jected to cold shock at 4 °C for different trial times (10, 20, 30 and 40 minutes) starting at 2 minutes post-fertilization. The optimum duration for cold shock was found to be 30 minutes. Triploids (3n=84) were distinguished from diploids (2n=56) by micromeasurements of erythrocytes and chromosome counts.