MONTANA FISH, WILDLIFE & PARKS
ANNUAL TEST DETECTS WHIRLING DISEASE AT MILES CITY HATCHERY
Montana Fish, Wildlife & Parks officials placed the state's Miles City Hatchery under quarantine this week after whirling disease was detected in a sample of young rainbow trout collected for annual fish-health tests.
"Our primary aim with annual tests is to maintain the high standard of health at each of Montana's 10 fish hatcheries," said Gary Bertellotti, chief of FWP's hatchery bureau in Helena. "We collected a total of 60 trout for health testing and detected an extremely low level of whirling disease infection in one sample."
This is the first time whirling disease has been detected in a state hatchery. Whirling disease is a potentially fatal ailment of trout and salmon caused by a microscopic parasite with a complex two-host lifecycle. The parasite consumes the cartilage of young fish, which cause the fish to swim erratically. It was first found in Montana in 1994.
The Miles City Hatchery is the state's warm-water fish hatchery where 50 million walleye fry and two million walleye fingerlings are raised annually for stocking in Montana lakes and reservoirs. The hatchery also raises large and small mouth bass, northern pike, tiger muskie, channel catfish, sauger, and pallid sturgeon. None of those warm-water fish are susceptible to the whirling disease parasite.
Bertellotti said the Miles City Hatchery raises small trout at the facility as a food source for bass brood stock and as a detection species for certain virus, bacteria, and parasites that cause fish diseases. The 60 fish collected for the test where separated into 12 batches with each batch containing five fish. Whirling disease was detected in only one of the samples.
Under the quarantine, which is designed to substantially reduce the risk of spreading disease, fish cannot be transported from the facility.
"Plans are now being developed to ensure that Miles City Hatchery is safe and that no infected fish or whirling disease organisms will leave the hatchery and FWP will be able to produce warm water fish for stocking next spring." Bertellotti said. "We've collected more trout for testing from the Miles City Hatchery and are retesting the samples we originally tested. Our policy is to sample more fish to confirm the original test results before we take additional action."
Because the water source for the hatchery is primarily the Yellowstone River, Bertellotti said officials suspect that the fish were exposed to the whirling disease parasite in the hatchery's rearing tanks supplied by Yellowstone River water. "It's too early to draw any conclusions about the Yellowstone River, but we have to assume that the parasite came in either with the water or perhaps from birds that utilize the hatchery ponds after eating infected fish elsewhere in the state."
Bertellotti cautioned that the tests results are preliminary and that additional tests are underway. He said several fish were placed in special cages this week to determine the presence of whirling disease in the Yellowstone River near the hatchery intake, the hatchery intake settling pond, the hatchery building, and in the effluent pond.
Fish from these cages will be collected after 10 days, brought to FWP's whirling disease experimental lab in Bozeman and examined.
Additional experiment stations will be placed in the Yellowstone drainage in the spring. These stations will monitor whirling disease infection levels at different locations in the Yellowstone River system.
Bertellotti said the quarantine will be lifted when additional tests show the parasite is eliminated from the Miles City Hatchery, but a partial lifting of the quarantine may be possible if follow-up tests now underway show other fish are not infected. Bertellotti stressed, however, that no infected fish would be stocked into Montana waters.
Under an agreement with the U.S. Fish and Wildlife Service, FWP obtain ownership of the Miles City Hatchery in 1983. Since then more than $10 million dollars has been spent to renovate and expand the hatchery to meet growing needs for warm water fish throughout Montana.
-fwp-
ANNUAL TEST DETECTS WHIRLING DISEASE AT MILES CITY HATCHERY
Montana Fish, Wildlife & Parks officials placed the state's Miles City Hatchery under quarantine this week after whirling disease was detected in a sample of young rainbow trout collected for annual fish-health tests.
"Our primary aim with annual tests is to maintain the high standard of health at each of Montana's 10 fish hatcheries," said Gary Bertellotti, chief of FWP's hatchery bureau in Helena. "We collected a total of 60 trout for health testing and detected an extremely low level of whirling disease infection in one sample."
This is the first time whirling disease has been detected in a state hatchery. Whirling disease is a potentially fatal ailment of trout and salmon caused by a microscopic parasite with a complex two-host lifecycle. The parasite consumes the cartilage of young fish, which cause the fish to swim erratically. It was first found in Montana in 1994.
The Miles City Hatchery is the state's warm-water fish hatchery where 50 million walleye fry and two million walleye fingerlings are raised annually for stocking in Montana lakes and reservoirs. The hatchery also raises large and small mouth bass, northern pike, tiger muskie, channel catfish, sauger, and pallid sturgeon. None of those warm-water fish are susceptible to the whirling disease parasite.
Bertellotti said the Miles City Hatchery raises small trout at the facility as a food source for bass brood stock and as a detection species for certain virus, bacteria, and parasites that cause fish diseases. The 60 fish collected for the test where separated into 12 batches with each batch containing five fish. Whirling disease was detected in only one of the samples.
Under the quarantine, which is designed to substantially reduce the risk of spreading disease, fish cannot be transported from the facility.
"Plans are now being developed to ensure that Miles City Hatchery is safe and that no infected fish or whirling disease organisms will leave the hatchery and FWP will be able to produce warm water fish for stocking next spring." Bertellotti said. "We've collected more trout for testing from the Miles City Hatchery and are retesting the samples we originally tested. Our policy is to sample more fish to confirm the original test results before we take additional action."
Because the water source for the hatchery is primarily the Yellowstone River, Bertellotti said officials suspect that the fish were exposed to the whirling disease parasite in the hatchery's rearing tanks supplied by Yellowstone River water. "It's too early to draw any conclusions about the Yellowstone River, but we have to assume that the parasite came in either with the water or perhaps from birds that utilize the hatchery ponds after eating infected fish elsewhere in the state."
Bertellotti cautioned that the tests results are preliminary and that additional tests are underway. He said several fish were placed in special cages this week to determine the presence of whirling disease in the Yellowstone River near the hatchery intake, the hatchery intake settling pond, the hatchery building, and in the effluent pond.
Fish from these cages will be collected after 10 days, brought to FWP's whirling disease experimental lab in Bozeman and examined.
Additional experiment stations will be placed in the Yellowstone drainage in the spring. These stations will monitor whirling disease infection levels at different locations in the Yellowstone River system.
Bertellotti said the quarantine will be lifted when additional tests show the parasite is eliminated from the Miles City Hatchery, but a partial lifting of the quarantine may be possible if follow-up tests now underway show other fish are not infected. Bertellotti stressed, however, that no infected fish would be stocked into Montana waters.
Under an agreement with the U.S. Fish and Wildlife Service, FWP obtain ownership of the Miles City Hatchery in 1983. Since then more than $10 million dollars has been spent to renovate and expand the hatchery to meet growing needs for warm water fish throughout Montana.
-fwp-
