Rebecca Williams

50 years ago, officials put Pacific salmon into the Great Lakes to eat an invasive fish called the alewife, and a huge sport fishery was born. These days, you can still catch both coho and chinook salmon. But people are worried there’s not enough food in Lake Michigan for chinook salmon.

Researchers say they’ve found grass carp eggs in the Sandusky River for the first time. The river flows into Lake Erie near Cedar Point. Grass carp are a type of invasive Asian carp. This is the first time scientists have had direct confirmation that the fish are reproducing in the river.