Researchers Discovered Endangered Mussels in St. Croix River Believed to Have Existed For Over a Century

Researchers recently discovered a cluster of endangered native mussels in the St. Croix River, and some of them are still alive, scientists are convinced they are more than a century old. The finding was surprising, according to experts, because the host fish which the mussels are supposed to reproduce had been unable to migrate upstream since the St. Croix Falls Dam close to St. Croix Falls, Wisconsin, was built in 1907.