DETROIT – People visiting Lake Michigan may be welcomed by an abundance of dead fish.
One species is experiencing a seasonal die-off extending from Muskegon, Michigan all the way up to Cross Village, Michigan – which is more than 200 miles north – and out to Lake Michigan's Beaver Island.
Alewife, a small prey fish that can reach 2 to 9 inches in length, went through this summertime event frequently 20-60 years ago, but the occurrence has since been rare.
“The die-off is larger than normal this year and something we have not seen in years,” said Jay Wesley, Lake Michigan basin coordinator for the Michigan Department of Natural Resources.
The Michigan Department of Natural Resources believes the die-off is caused by a combination of poor over-winter conditions, temperature changes and spawning stress – not by pollution or disease.
Not native to Michigan, alewives migrated from the Atlantic Ocean into the Great Lakes through the Welland Canal in the 1920s, the Michigan Department of Natural Resources said.
The Michigan Department of Natural Resources also said the small fish spend most of the year in deep, cold waters, migrating to the nearshore areas to spawn and search for food. Some alewives come out of winter in a weakened state and don’t tolerate changing conditions such as large temperature swings, the DNR said.
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The Michigan Department of Natural Resources along with federal agencies annually collect alewives to evaluate their condition and abundance in Lake Michigan.
This article originally appeared on Detroit Free Press: Lake Michigan shores collect dead alewife fish in rare die-off