COMPARISON OF TWO STRAINS OF CHANNEL CATFISH Ictalurus punctatus FOR INDUCED OVULATION IN THE EARLY SPAWNING SEASON TO PRODUCE CHANNEL CATFISH Ictalurus punctatus ♀ X BLUE CATFISH Ictalurus furcatus ♂ HYBRID CATFISH EMBRYOS

Sheng Dong*, Dayan A. Perera, Ahmed S. Alsaqufi, Ramjie Y. Odin, Guyu Qin, Rex A. Dunham
 
School of Fisheries, Aquaculture, and Aquatic Sciences
Auburn University
Auburn, AL 36849
szd0042@auburn.edu

Currently catfish production in the United States has decreased by 50% from its peak levels in 2003. This is due to competition from foreign imports from Asia, rising feed and labor costs. Genetic enhancement is a partial solution to the survival and recovery of the catfish industry. Genetic selection for early spawning is a direct approach to extend the spawning season and grow larger numbers and different size classes of fingerlings at different times of the year. The channel catfish (Ictalurus punctatus) ♀ X blue catfish (Ictalurus furcatus) ♂ hybrid catfish has superior performance in respect to survival, growth rate, feed conversion, low dissolved oxygen, and fillet yields. Presently hybrid catfish account for 75% of total production of catfish in the United States. Producing hybrids early in the year would have various advantages.

Spawning times vary among channel catfish strains. Under commercial conditions and on commercial farms, one catfish strain appears to spawn earlier and at lower temperatures than other strains. This performance trait could be genetic or environmental, and has not been compared to other strains at a single location. If it is genetic, this early spawning trait may make these fish amenable to early induced spawning to produce hybrids early in the year.

The early spawning strain was compared to the Kansas strain for early season spawning using artificial spawning methods over a period of three years. Data on ovulation rate, hatching rate and fry production were collected. There were no significant differences in ovulation, fertilization rate, hatching rate and fry production for early season spawning between the early spawning strain and the Kansas strain. The early season spawning strain may not be genetically unique for early season spawning compared to other strains, environmental factors at certain farms may contribute to early spawning of this strain, Kansas, which is from a northerly climate, may also have the potential for early spawning or early natural spawning and early response to induced spawning may not be genetically correlated. Additional experiments with other strains are needed to reach a more definitive conclusion.