Yellowstone National Park
Eighteen species of fish live in Yellowstone, including the Yellowstone cutthroat trout. Many anglers want this fish, and most of the fish live in Yellowstone. The Yellowstone cutthroat trout has faced several threats since the 1980s. Someone may have illegally added lake trout, an invasive species, to Yellowstone Lake. They eat the smaller cutthroat trout. An ongoing drought has caused problems for the cutthroat. A parasite called whirling disease kills younger fish. Since 2001, a "catch and release" law applies to all native sport fish species caught in Yellowstone waters.