Meristic Differences Between Anadromous and Freshwater-Resident Arctic Char (Salvelinus alpinus) in the Sagavanirktok River Drainage, Alaska

Both anadromous and freshwater-resident populations of Arctic char (Salvelinus alpinus) occur in the Sagavanirktok River drainage, Alaska. A comparison of the gill-raker and pyloric-caeca counts of populations of the two types revealed that anadromous fish had lower gill-raker and pyloric-caeca counts than freshwater-resident fish. Freshwater-resident populations correspond meristically to McPhail's Eastern Arctic form, and anadromous population scor-respond to his Western Arctic–Bering Sea form (McPhail, J. Fish. Res. Bd. Canada 18: 793–816, 1961). It is suggested that the former was the original inhabitant of the area but has been replaced by the latter except in inaccessible, headwater lakes.