DETROIT – The Michigan Department of Natural Resources will not collect eggs from Great Lakes muskellunge in the Detroit River this month because of a widespread infection of viral hemorrhagic septicemia virus that has killed fish in Lake St. Clair.
An increasing number of dead muskellunge have also been found in the Detroit River.
The DNR usually collects eggs from the muskellunge to be reared at Wolf Lake State Fish Hatchery in Mattawan. The fish are then stocked in bodies of water around the state in the fall.
DNR fisheries managers determined the risk of contaminating the hatchery is too great to proceed with rearing efforts.
“VHSv has never been found in one of our state fish hatcheries and it is our intent to keep it that way,” said the DNR’s fish production manager, Ed Eisch. “We know it is safer to place our muskellunge rearing program on hold this year rather than bringing in these Detroit River muskellunge eggs and risk infecting our hatchery.”
VHSv is a contagious pathogen that causes the fish’s blood vessels to leak, according to the DNR. It can show as bloody patches on the skin.
It is known to infect more than 30 species of Great Lakes fish and has been found in lakes Superior, Huron, Erie and Ontario, as well as some inland lakes.
Lake sturgeon and walleye are very resistant to VHSv, while other fish such as bluegill, largemouth bass, muskellunge, gizzard shad and round goby are very susceptible, the DNR said.
According to the DNR, if VHSv were to be found at Wolf Lake State Fish Hatchery, there is a chance that the facility would need to be destroyed and landfilled. This could include all steelhead and Chinook salmon. As a result, future fish stocking efforts would be affected statewide.
“The tests we use to detect VHSv are good, but they are not 100 percent guaranteed,” Eisch said. “The last thing we want to do is move this virus to lakes where it currently does not exist.”
The DNR has been working to develop additional egg sources for its muskellunge rearing program, but the populations are not at a point where they can serve in that role this year.
The DNR does not believe a one-year gap in its stocking efforts will be a detriment to this fishery or to the program, as muskellunge are a long-lived species.