If you're heading to a Lake Michigan beach to cool off, you just may encounter a stinky and unsightly visitor -- dead alewives are littering some areas of the lakefront. 

The smell isn't pleasant and they are an eyesore at the area parks. It's something that happens every year. 

These fish come close to the shore to mate, but they die off when the temperature of the water suddenly rises.

"Alewives are an invasive species to Lake Michigan, getting into the Great Lakes via the Welland Canal," said Jennifer Serano with the Wisconsin Department of Natural Resources.

"Since they are a salt water fish, they have issues regulating their bodies to a fresh water environment. When near shore waters start to warm and they come into the near shore areas to spawn, many cannot stand up to those to stressors and die."

It's posing a problem for people coming here to walk their dogs. One woman told me she had a hard time keeping her puppy from eating the little guys.

"We have not heard of large numbers of fish dying this year, so right now it would be classified as a normal and small occurrence. It might be up a little bit from 2015 but that is always hard to judge," Serano said.