About twenty-five species of sturgeon are distributed throughout the northern hemisphere and nowhere else in the world. The Atlantic sturgeon which inhabits North Carolina's waterways is among two groups of fish that migrate between salt and freshwater systems. It is the state's largest inland fish and can reach twelve feet in length and weigh over 500 pounds. This fish mates between late March and May and prefers rivers like the Cape Fear, Tar, Roanoke, and Chowan. Until 1900, the Atlantic sturgeon was one of the state's chief commercial fisheries. Overfishing caused its numbers to plummet, and the sturgeon population remains small into the twenty-first century.