Lake Michigan has become dramatically clearer in last 20 years — but at a steep cost
“Clearer is not necessarily better,” said Robert Shuchman, co-director of the Michigan Tech Research Institute. “Clearer water means less phytoplankton in the water column, and they’re the basic building block in the food web. The idea is, the little fish eat algae, and the bigger fish eat the little fish.
“There are some folks out there now that think Lake Michigan and Huron could become ecological deserts from a fishing standpoint. The food web could totally collapse because you don’t have the various organisms you need to sustain it.”
For ages, the phytoplankton fed the zooplankton, which were eaten by small, foraging fish. As the fast-filtering mussels reduce the plankton populations, there isn’t enough food to support the diet of many foraging fish. In addition, there’s not enough plankton or nutrients clouding the water to hide these small prey fish from predator fish....