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Great Lakes

Invasive Species and Beaches

The weather is perfect. You’ve got your beach towel, your sunscreen and your favorite book. You’re ready to spend a relaxing day at the beach. And then, your afternoon is hijacked by two words: Beach Closed.

If you live in or around the Great Lakes, you’ve probably noticed these warnings popping up more frequently. Beach closings can be caused by many factors, but aquatic invasive species, which enter the Great Lakes through commercial shipping and recreational boating, play a role.

In addition to closing down your favorite swimming spot, aquatic invasive species can cause injuries to swimmers, do serious damage to docks, boats and anchors, and generally ruin your day at the beach.

Here’ s a look at some of the top offenders, and what we can do to take our beaches back.

Zebra Mussels
Beaches close when the daily maximum standards for E. coli are met, and zebra mussels have a hand in creating the perfect environment for this bacteria. By consuming plankton and other microorganisms in the Great Lakes, zebra mussels clear the water so sunlight can penetrate further down. This allows other aquatic plants such as mat-forming green algae to thrive—the same type of algae that clogs up coastlines and serves as a breeding ground for E.coli.

If that weren’t enough, zebra mussels have other ways to ruin your enjoyment of Great Lakes beaches and coastlines. With their razor-sharp edges, they’ve been known to cut swimmer’s feet. They also have a nasty habit of growing on docks, boats, and anchors, creating a serious headache for watersport enthusiasts.

This small, silvery fish may look innocent, but packs a serious potential to ruin your day at the beach. Alewives were originally ocean fish before they invaded the Great Lakes. They prefer cooler water temperatures, so when the water warms up quickly, it can kill them if they don’t move to deeper parts of the lake in time. When they die, they die off in mass, clogging up shorelines and producing a highly unpleasant smell.

This aggressive wetland grass is quickly taking over coastal marshes and inland wetlands. With the ability to grow up to 15 feet, phragmites impede the growth of native plants, which in turn harms the rest of the coastal ecosystem. As this species spreads, they’ll grow along our beaches, ruining our beautiful scenic coastlines. And the dense pockets they grow in provide shelter for any beachgoer’s least-favorite insects: ticks, flies and mosquitoes.

Although these species are already present in our Great Lakes, there is good news. The Nature Conservancy is working hard to manage current aquatic invasive species populations and stop the spread of new threats.

Help fight the spread of aquatic invasive species by supporting our work today.

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