Fish Use of Coastal Waters of the Alaskan Beaufort Sea: A Review

A biologically important feature of the Beaufort Sea is the occurrence of a band of relatively warm and brackish water (5–10 C, 10–25‰) that lies adjacent to the shoreline in summer. This estuarine band extends the length of the coast (750 km); it is very narrow (usually 2–10 km wide) and is often distinctly different from adjacent marine waters (-1 to 3 C, 27–32‰). The band provides important feeding habitat for anadromous and marine fishes. Dominant anadromous species are Arctic cisco Coregonus autumnalis, least cisco C. sardinella, and Arctic char Salvelinus alpinus which enter previously frozen nearshore waters each summer and feed extensively on an abundant supply of epibenthic mysids and amphipods. These fishes disperse parallel to the coastline, remaining in the estuarine band. Dominant marine species are Arctic cod Boreogadus saida and fourhorn sculpin Myoxocephalus quadricornis, which enter nearshore waters later in summer as salinities increase. In winter, the estuarine band is absent and most anadromous species return to North Slope drainages to spawn or overwinter; marine species remain under nearshore ice but eventually vacate shallow waters, which freeze solid to a depth of 2 m. Received May 21, 1983 Accepted March 21, 1984