Four decades ago, salmon were added to the Great Lakes by Michigan fisheries biologists. In the following years, the fishing industry flourished as did the salmon. Cars hauling boats would be lined up with anglers just waiting to get out in the lakes and catch fish. But now, things have changed.
The invasive mussels came in and altered the food web. Alewives, one of salmons' favorite fish to feed on, have mostly disappeared from the Great Lakes. Without enough time, the salmon were unable to adapt their diet as their food supply disappeared. Walleye, a native species, have returned to the lakes and are also responsible for eating the salmon. Last fall the Lake Michigan salmon never showed up at spawning time. Things aren't looking good for the salmon.
Listen to the NPR Story for more details.
Photo credit: Coho salmon - muskegon-mi.gov