Rapid temperature hike causes unusual fish die off in Little Glen Lake

From staff reports

In early June, Glen Lake Association (GLA) watershed biologist Rob Karner reported a significant fish die off, the likes of which he had never before seen in his more than 40 years of observing the lakes and rivers in the Glen Lakes watershed. The die off included at least four species—perch, small mouth bass, northern long nosed gar, and sand shiners. 

The dead fish were found along the shallow north shore of Little Glen Lake over a three-day period. Strong south winds pushed the dying and dead fish to the north shore, and dead fish were visible along the entire shore, from the picnic area on M-109 near the Sleeping Bear Dune Climb to the Narrows Bridge. Karner visited at least three properties and made initial counts of 75 to 100 dead fish for each property. His rough estimate based on the limited sample size suggested that more than 1,000 fish died. The age and size of the fish varied.

Karner suspects the cause may be weather related. The die off coincided with a rapid increase in lake water temperatures during the span of only a few days in early June, which may have caused stress on the fish population. The fish die off was reported to the Michigan Department of Natural Resources, which confirmed that a few lakes in the region were also experiencing a similar die off during the same time period.

Lake temperatures have cooled since the rapid increase in early June.

Please contact GLA watershed biologist Rob Karner to report any future observations of fish die offs that seem to be beyond normal fish mortality—defined as a few dead fish on your shore for the summer.