LAKE MICHIGAN SHORELINE - We are in the heart of summer, and the one thing on your mind may be getting in the water and cooling off, but there are a few things you may want to keep in mind before you bring your family to the beach.
Piles of dead alewives - tiny, silvery fish - are lining the beaches of Lake Michigan in Wisconsin, rolling in wave by wave. It’s a common occurrence this time of year in late spring and early summer. It’s a little delayed this year from the colder spring the area endured.
“They are coming in a bit challenged to spawn and we do see some die-offs. We have been seeing this, more or less, ever since they invaded Lake Michigan,” explained DNR Fisheries Biologist Scott Hansen.
The fish are actually native to the Atlantic Ocean. A member of the herring family, they are an invasive saltwater fish, that entered the Great Lakes through the Lawrence Seaway, bypassed Niagra Falls through the Welland Canal, and swam their way into Lake Michigan in 1949. A shocking statistic, they’ve adapted and now make up over 50% of the lake's biomass, which includes all fish and plant life combined!
This year, the reports and the piles keep growing and it’s a little bit more than the years past. But if you’ve lived along these shorelines, you remember 20 years ago, it was much worse.
Hitting historical highs upon invasion, the flashback of massive fish piles, flares up for some local beachgoers.
“There were wind rows with fish feet deep on the beach, so now when we see a little uptick, certainly people are more aware of that,” said Hansen.
Below the water, it’s the battle of invasive species. The zebra mussel is depleting the lake of necessary nutrients for the only native fish, the lake trout, which eats the same plankton as alewives. So, how do biologists go about fixing something like this? By adding a predator, of course, one that loves to specifically snack on alewives: the non-native salmon!
“The salmon are hitting them from the top down and squeezing it. So right now we have is a little bit of a bump now over the last 5 years or so in the alewife population and that’s back to where we started, where people are starting to see more of these fish die-offs and natural processes going on and they are washing up on our beaches,” explained Hansen.
It’s up to whoever owns the property to clean up these beaches of these fish. Otherwise, as we go through the rest of this summer, the water is looking clearer with less fish washing up and we are on the decline.
This article was written by Brittney Merlot for WGBA.