Lake Macatawa fish die-off due to viral hemorrhagic septicemia, DNR confirms

[TNDiver]

An ongoing fish die-off on Lake Macatawa, near Holland in Ottawa County, stems from the virus responsible for causing viral hemorrhagic septicemia, or VHS, the Michigan Department of Natural Resources recently confirmed.

Reports of large numbers of dead and dying fish near the outlet channel of Lake Macatawa began coming in around mid-April through the DNR's Eyes in the Field online reporting app. DNR Fisheries Division staff members were dispatched to attempt to collect specimens suitable for analysis by fish health professionals at Michigan State University's Aquatic Animal Health Lab. Because the fish had been dead for quite a while, most were unsuitable for analysis.

One pumpkinseed sunfish from the original investigation was fresh enough to be taken to the lab. While MSU was conducting the analysis, more reports of dead fish came in, so a second attempt was made to collect specimens. This time, seven freshwater drum, also known as sheepshead, were collected and delivered to the lab. Eventually, the pumpkinseed sunfish and six of the seven drum tested positive for the virus.

"The die-off mostly affected freshwater drum, with smaller numbers of gizzard shad and sunfish also being impacted," said DNR Fisheries Division Assistant Chief Ed Eisch. "The virus that causes VHS is known to have been in the Great Lakes basin since approximately 2005."

The virus has periodically caused mortality in gizzard shad and muskellunge populations in the Lake St. Clair/Lake Erie/Detroit River system. Given the rising water temperatures, the current outbreak in Lake Macatawa is probably winding down and it is not expected to have any lasting effect on the lake's fish populations.

While VHS has only been in the region for a short time, it has the potential to cause significant mortality in species important to anglers, so minimizing its spread is critical. Boaters and anglers can play a substantial role in limiting the effects of pathogens such as this virus.

"Disinfecting gear that comes into contact with water, as well as making sure that you clean, drain and dry your boat and trailer between going from one water body to the next is one of the best ways to keep such organisms from spreading across the state," said Eisch. "Doing so is always a good practice, but especially if you've been in Lake Macatawa this spring."

This virus poses no threat to humans or pets that come into contact with potentially infected water.

Learn more about viral hemorrhagic septicemia and other fish diseases at Michigan.gov/FishHealth.