CHANNEL CATFISH BEGINNING TO SPAWN AT RATHBUN HATCHERY
IA DNR
June 2003
MORAVIA - Romance is in the air for roughly 250 channel catfish at the Rathbun fish hatchery that are beginning their annual spawn. The DNR hopes the 2003 spawn will result in about 1 million catfish fry by the end of June.
Hatchery staff placed cream cans in the catfish ponds Monday and will monitor the cans three days per week until the spawn is complete. The cream cans serve as a nest for the captive catfish. In the wild, channel catfish will search out hallow logs or cavities in the riverbank as places to spawn.
"Male catfish are pretty aggressive during the spawn," said Chris Clouse with the Rathbun hatchery. "The males will either chase or, in some cases, drag females into the cream can to spawn. And the males can spawn with more than one female."
Males will remain in the cream can after the female has released her eggs to guard the nest. Clouse said it can be a bit dicey to get the males out of the cans so workers can retrieve the eggs.
The eggs will then get the "Rathbun Process." Catfish eggs are laid in a gelatinous mass resembling thick tapioca. After collection, the eggs are placed in a chemical solution to remove the gelatinous material. The eggs can then be placed in the jars that incubated walleye eggs two months earlier. Channel catfish eggs will hatch in six to 10 days.
These newly hatched catfish will remain at the hatchery for up to 15 months. By next May, the 4- to 5-inch fish will be moved to county conservation board lakes, placed in cages and grown to 10 to 12 inches before being released in the lake. Catfish remaining at the hatchery will be stocked when they reach 7 to 10 inches.
The DNR stocks more than 250,000 channel catfish statewide, in nearly all the lakes managed by the DNR, except the federal reservoirs. An additional 100,000 catfish are used for the farm pond stocking program. Excess catfish are traded with other states.
