By JANE HOUIN
Ohio correspondent

COLUMBUS, Ohio — Good news for Ohio fishermen and women: Castalia and London state fish hatcheries are free of Viral Hemorrhagic Septicemia (VHS), according to the Ohio Department of Natural Resources (ODNR) Division of Wildlife. As a result, the fall stocking of most muskies and trout will be able to proceed on schedule.

VHS is a virus that can cause death in fish, but is not a public health threat. This dangerously contagious or infectious disease must be reported under state law. VHS was introduced into the wild fish population by an invasive species; it is not harmful to humans.
Muskellunge from Clear Fork Reservoir sampled during routine egg collection in late April of this year tested positive for the virus in tests completed by the United States Fish and Wildlife Service (FWS) June 2. No fish kill was associated with the presence of the virus at Clear Fork.

This discovery occurred after three routine but significant events had occurred which created an unknown state of events for Ohio’s state hatcheries. The first was when eggs that had been collected from the reservoir were taken to the London State Fish Hatchery for muskie-rearing and subsequent stocking.

Second, rainbow trout at London were transferred to the Castalia State Fish Hatchery to grow out for the state’s fall trout stocking effort. Finally, surplus muskie fry from the London Hatchery were stocked at Alum Creek Lake.

On June 2, the Division of Wildlife was notified of the potential problem. It immediately contacted the Ohio Department of Agriculture (ODA) – which has authority for fish health in the state – regarding the VHS-positive results and the activity related to Clear Fork that had occurred at the hatcheries.

The ODA placed the Castalia and London hatcheries under quarantine until three consecutive negative tests for VHS could be confirmed for each location. Additionally, the ODNR and the FWS sampled six locations from Clear Fork Reservoir downstream to the confluence of the Muskingum and Ohio rivers. All test results were negative for VHS.

Testing for the virus at the London and Castalia hatcheries has been completed. On Sept. 19, London State Hatchery was cleared and the Castalia Fish Hatchery had its quarantine lifted Sept. 22.
With these clearances, fall stocking of muskellunge and rainbow trout will proceed as scheduled. Twenty-six Ohio lakes will be stocked with 25,000 catchable rainbow trout throughout October. Advanced muskie fingerlings reared from the eggs taken earlier this year from the Clear Fork Reservoir were stocked in Clear Fork Sept. 23 and in Alum Creek Lake Sept. 24.

In the Great Lakes region, VHS has been found in the waters of lakes Huron, St. Clair, Erie, Ontario and the St. Lawrence River. Because of its high mortality and severe economic consequences, VHS is classified as a reportable disease by the World Organization for Animal Health (OIE).

Previously, VHS was though to only affect trout and a few other freshwater fish raised for commercial aquaculture in Europe. The recent outbreak in the Great Lakes region, however, appears to be a new strain of the virus, resulting in die-offs of muskies, smallmouth bass, northern pike, freshwater drum, gizzard shad, yellow perch, black crappie, bluegill, rock bass, white bass, red horse sucker, blunt nose sucker, round goby and walleye.
It is not known how VHS was transferred to the Great Lakes or how long it has been in the ecosystem.

While some fish show no external signs, others show signs including bulging eyes, bloated abdomens, inactive or overactive behavior and hemorrhaging in the eyes, skin, gills and at the base of the fins. Infected fish may also have lesions that look like those caused by other fish diseases, making testing a requirement to determine actual infection.

Sport fishermen and recreational boaters are asked to adhere to good biosecurity practices while fishing or boating in waters where VHS has been found. Such practices include thoroughly cleaning fishing equipment, boats and trailers before using them in a new body of water and not transferring fish from one body of water to another.