Chemical Separation of Channel Catfish Egg Masses

Abstract

Abstract Chemical methods were developed and evaluated for dissolving the matrix surrounding eggs of channel catfish (Ictalurus punctatus), which permits eggs to be incubated in cylindrical jars. Screening tests identified several dissolving agents, and four solutions appeared most suitable: (1) 1.5% Na2SO3; (2) 1.5% Na2SO3 plus 0.2% papain; (3) 1.5% L-cysteine-HCl plus 0.2% papain; and (4) 1.0% Na2SO3, 0.5% L-cysteine-HCl plus 0.2% papain. Production-level testing on whole egg masses demonstrated that hatching success of channel catfish eggs chemically separated and incubated in jars averaged 20.5% higher than with traditional trough-and-paddle incubation methods. No significant differences in fry deformities or survival were found among the nine treatments and controls. A trend toward higher percent hatch and higher fry viability was detected when eggs were separated from medium-sized egg masses (601–900 g) more than 24 h after the eggs were spawned. Chemical separation of eggs reduced fungal disease problems and labor associated with egg incubation. This process has been used for several years in a variety of cultural situations. Other fish species with adhesive eggs have been successfully incubated with variations of this technique.