The Shasta crayfish (Pacifastacus fortis), also known as the placi crayfish, is an endangered crayfish species endemic to California. It is found only in isolated spots on the Pit and Fall Rivers. It has always had a very small native range, and that range has been significantly fragmented by such human activities as damming, mining, and agriculture. To make matters worse, the signal crayfish, a recently introduced species, has very successfully outcompeted the Shasta crayfish in much of its range. The Pit River Fish Hatchery was closed in order to protect this species. The animal requires a constant, steady, and untainted flow of fresh water to survive. Further steps in the recovery plan for the species are underway.