By Paul J Sniadecki, Board Director and DNR Supplied Data
Largemouth bass virus, which was previously found in Cedar Lake in Iosco County, has now been confirmed in Alpena County’s Beaver Lake and Montmorency County’s Avalon Lake. Prior to its detection in Cedar Lake, the virus had not been detected in Michigan for more than 15 years. It previously affected Michigan largemouth bass in different lakes in the early 2000s.
These latest discoveries indicate the virus is spreading northward in Michigan, according to the MI Department of Natural Resources. “The largemouth bass virus likely compromised the immune system of smallmouth bass in Beaver Lake, causing secondary bacterial infections to become more lethal and allowed the virus to be a direct factor in the fish kill,” said Gary Whelan, the DNR Fisheries Division’s research manager. Because these latest detections are at the northern edge of where LMBV has been found, we may see different responses than what was documented in southern Michigan.”
In the early 2000s, the pathogen killed 10 to 20 percent of the larger adult largemouth bass in southern Michigan lakes at first exposure, with populations recovering in a few years.