850,000 Catfish Doomed : Disease Forces Imperial Valley Hatchery to Cease Operations

After 16 years of successfully raising a special breed of channel catfish for the purpose of stocking public waters, the Department of Fish and Game’s Imperial Valley Warmwater Fish Hatchery has been forced to cease operations.

The recent discovery of a disease--enteric septicemia--has prompted the closure of the only state operated catfish hatchery and spells doom for nearly 850,000 sub-yearling class channel catfish, which were destined for Southland lakes and ponds.

Wayne L. Parker, manager of the hatchery, located at Niland in Imperial County, said the fish have an estimated value of $126,000. Cause of the disease--almost always fatal to channel catfish, but not a threat to humans--has not yet been determined.

Approximately 130,000 sub-yearling catfish have succumbed to the disease so far, according to Parker, and all were located in one of several ponds at the hatchery.

The long-range effects and costs are impossible to predict at this time, DFG officials said, because of the involvement of broodstock representing 16 years of concentrated selection and breeding to produce a superior strain of channel catfish known to exist only at the Imperial Valley facility.

The DFG is going to destroy all but 700 of the infected catfish, which will be saved to provide future broodstock in order to avoid a catastrophic loss of the special breed.

Once the eggs are collected from the brooders, a process scheduled to begin in May of 1988, the broodstock fish would also be destroyed.

Six weeks are required to dispose of the hatchery’s catfish population, Parker said. Individual selection of 700 present and future broodstock fish is a time consuming process which requires careful examination of each of the 850,000 fish.

The decision to destroy the fish was made in order to lessen the chance that infection will spread to private hatcheries and wild catfish populations.

According to Chuck Marshall, a fisheries biologist for the DFG, samples of catfish will be taken from privately owned hatcheries in October in an effort to determine the full extent of the problem.

Just how the problem will be solved at the Imperial Valley facility hasn’t been decided. One method under consideration, according to Dr. Martin Chin, a DFG fish pathologist, is to allow the earthen ponds to dry up, turn the soil and allow them to dry a second time. It is hoped this process will kill the bacteria.

A final decision on how to eradicate the disease will not be made, however, until all other avenues have been explored.

“As far as I can tell at this time, we will be the first growers to ever try to get rid of the disease,” Chin said.

The disease is fairly common in the Southeastern states and up until now has not been seen in Western catfish populations, according to Marshall.

Commercial growers in those states employ a medicine program that keeps the fish alive long enough to market--the fish infected with the disease are edible, according to the DFG.

“You can treat the disease and reduce amount of mortality,” Marshall said. “The medicine controls the disease, but it doesn’t eliminate it.

“What they do then is stop the treatment prior to marketing the fish. It’s a costly process.”

The outbreak of the disease in California was discovered when five dead catfish were found in one of the hatchery ponds on June 25.

Four days later, hundreds of dead fish were found in the pond.

About 500,000 yearling and sub-yearling channel catfish are planted statewide each year by Imperial Valley Hatchery personnel.

Several alternatives are being developed to provide replacement of catchable and sub-catchable catfish to fulfill normal stocking schedules for south state waters, according to Fred Worthly, a DFG manager based in the southern part of the state.

The DFG expects the hatchery to return to full production by May of 1988.