Effect of low-temperature incubation of channel catfish Ictalurus
punctatus eggs on development, survival, and growth
B.C.
Small, T.D. Bates-2001
Journal
of the World Aquaculture Society, 32(2): 189-194 (from Current Contents)
Abstract :
To
determine whether the embryonic period of channel catfish Ictalurus
punctatus could be extended at low temperatures, fertilized channel catfish
eggs were incubated at five constant water temperatures: 4, 11, 16, 21, and
26°C. Low-temperature incubation of catfish eggs extended the embryonic
period at 16 (244%) and 21°C (56%) when compared to the control hatchery
incubation temperature of 26°C. All eggs incubated at 4 and 11°C died
within 24-48 h. Developmental stage had a significant (P < 0.05) effect
on percent hatch at 16, 21, and 26°C. Eggs held at 16°C prior to embryonic
axis formation died within 48 h. Larvae from eggs hatched at 16°C were
incompletely developed and died upon acclimation to 26°C for growth tests.
Growth of fry reared at 26°C, following egg incubation at 21°C, paralleled
that of fry from eggs incubated at 26°C. The underdevelopment of fry at 16°C
combined with the significant effect of egg stage on survival at this
temperature suggests that 16°C is below the lower thermal tolerance limit
for normal development in this species. The period prior to the formation of
the embryonic axis may be considered a vulnerable stage in channel catfish
development. Increasing the embryonic period through low temperature
incubation would increase the duration of juvenile availability for
researchers and commercial operations.
(USDA ARS, Catfish Genet Res Unit, Stoneville, MS 38776, USA)