GRAND RAPIDS, Mich. (WOOD) — The beaches on Lake Michigan are pristine, but they weren’t always this way.

Lake Michigan has weathered seasons of smelly and slimy shores in decades past. The 1960s and ’70s were especially dire and demanded human intervention in order for clean water to be restored.

TWO MAIN PROBLEMS LEADING TO DISGUSTING BEACHES

During the ’60s and ’70s, Lake Michigan was battling two main problems: extra pollutants and invasive species gone wild.

Even though the Great Lakes are large, they are especially susceptible to pollutants. The Clean Water Act of 1972 helped to put restrictions on dumping and pollutants, gradually restoring the waters.

Invasive species had to be taken care of a different way. One in particular began swarming the waters of Lake Michigan by the late ’60s: alewife. It was so pervasive that piles of dead fish would litter the beaches, making a trip to the lake stench filled and gross. Bulldozers used to be brought in to clean area beaches after alewife die-offs to clear the carcasses off the sand for visitors to find a spot to sit.

This fish was introduced to Lake Michigan sometime in the late ’60s due to humans opening up the the St. Lawrence Seaway. The narrow strip of water became a big mover of commerce, allowing ships to travel from the Great Lakes out into the open waters of the Atlantic.

Prior to the creation of St. Lawrence Seaway, fish and ships that tried to travel into the Great Lakes system from the Atlantic were stopped by the massive elevation change between lakes Ontario and Erie. This elevation change is better known as Niagara Falls.

Alewife are thought to have hitched a ride in the ballast water of cargo ships entering the Great Lakes from the open sea. Soon, the small fish took over — multiplying rapidly and decimating the ecological balance of Lake Michigan. Scientists needed to find a solution fast.

They found it in salmon.

SALMON IN THE GREAT LAKES

Salmon are not native to Lake Michigan. The fish were caught in the Pacific and released into Lake Michigan back in the ’60s and early ’70s as a way to keep the alewife population under control. Salmon make perfect predators for alewife and quickly gobbled up the millions of pray fish, getting fatter in the process.

Recreational fishing gained a huge advantage with the introduction of coho and Chinook salmon into the Great Lakes. Each year, salmon fishing generates $2.5 billion for anglers in the region and just over $7 billion recreationally.

In addition, the salmon help to keep the alewife in check and our beaches free from massive piles of dead fish. Salmon are a huge leading cause of our clean beaches. In fact, salmon are credited for slashing the invasive alewife population by 90% of its peak.

THE STOCKING PROCESS

Salmon that are introduced into Lake Michigan do reproduce naturally, but the population must still be carefully managed and restocked by fish hatcheries each year.

Basin coordinator Jay Wesley for the Michigan Department of Natural Resources is in charge of determining how many salmon to release each year. He does this with the coordination and cooperation from several departments across Wisconsin, Illinois and Indiana. This year, about 2 million salmon were released into Lake Michigan during the spring months.

Here in West Michigan, the fish are stocked by local fish hatcheries, like the one in Wolf Lake. About 250,000 Chinook salmon were raised and then taken to the Grand River to acclimate for a couple of weeks before release.

The fish are small when this happens — this is intentional. The juvenile salmon begin imprinting on the local river they are placed in for two weeks. When it comes time to spawn, the salmon will remember the river water they came from and swim back into the Grand River to mate and lay more eggs.

According to Wesley, 80% to 90% of the salmon released will reproduce in the wild.

The DNR keeps a close watch on reproduction rates, as well as alewife population and how many salmon anglers are catching each season. It uses these numbers to plan how many salmon to release the following year. The goal is to keep Lake Michigan ecologically in balance and the waters clean.