Michigan is home to tiny jellyfish, but humans aren’t in danger

It may sound strange, but freshwater jellyfish, Craspedacusta sowerbyi, live in some Livingston County waterways.

Todd Wills, Lake Huron and Lake Erie research manager for Michigan DNR, said the jellyfish were only about the size of a penny and posed no threat to humans.

“They’re really small,” he said. “They’re not like the big, massive jellyfish you might see in the ocean.”

According to the Great Lakes Aquatic Non-Native Species Information System, freshwater jellyfish stings are not large or strong enough to penetrate human skin, but they can paralyze macroinvertebrates or small fish.

Wills also said that this particular species only takes on its jellyfish form once in a while.

The species is commonly found in shallow, slow-moving, or stagnant man-made bodies of water such as ornamental ponds, reservoirs, gravel pits, and quarries.

Freshwater jellyfish were first observed in Michigan in 1933. They are non-native or invasive species, meaning they are not native to Michigan. They are thought to have come to Michigan through the ornamental plant trade in the 1930s, Wills said.

Michigan's freshwater jellyfish are generally not much larger than a penny.

Jellyfish are native to the Yangtze River in China, which is the longest river in Asia and the third longest in the world.

The jellyfish species is found in Michigan lakes and rivers, as well as the Midwest and Great Lakes regions.

The species has been identified at nine different locations in the Livingston County area over the years:

  • Once in 1999 at Whitmore Lake
  • Once in 1999 at Hamburg Lake
  • Twice in 2002 at Island Lake Recreation Area
  • Once in 2005 in Island Lake Recreation Area
  • Once in 2005 at Shangrila Lake
  • Once in 2006 in Lyon Sud
  • Once in 2018 in Lyon Sud
  • Once in 2019 at Whitmore Lake

To learn more about freshwater jellyfish in Michigan or to view the interactive map, visit the species profile in the Great Lakes Aquatic Non-native Species Information System.

Sophia Lada is a journalist at the Livingston Daily. Contact her at [email protected] or 517-377-1065. Follow her on Twitter @sophia_lada.

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