Dolly Varden

Blue dots show rearing areas.
Blue crosshatching shows coastal feeding and migration areas.

Dolly Varden have adapted to the rigors of the climatic and physical environment of the arctic. For almost nine months of the year, the fish are confined to relatively small reaches of stream and river channels for overwintering. The available overwintering habitat is critical to their survival and is considered to be the major limiting factor for populations of arctic fishes. After break-up, which begins in late May or early June, the distribution of Dolly Varden expands to streams and river channels that were previously frozen, and to the nearshore coastal waters for feeding and rearing. Unobstructed migration to feeding areas is important if Dolly Varden are to make the best use of the limited open water season in the Arctic. During this short period, the fish grow, accumulating fats to aid in their survival through the winter.

Juvenile Dolly Varden remain in the rivers for several years. Between the ages of two and four years, they complete their transformation to smolt. The anadromous fish then migrate to nearshore coastal waters where they spend the summer months feeding on macroinvertebrates. Dolly Varden maintain a strong fidelity to overwintering and spawning areas in the rivers they return to in late August through September. Spawning may occur from August through late September. Overwintering and spawning areas are associated with springs which flow year round. Dolly Varden generally mature after five years.

References

Craig P. 1984. Fish use of coastal waters of the Alaskan Beaufort Sea: a review. Transactions of the American Fisheries Society 113:265-282.

Craig, P. 1989. An introduction to anadromous fish in the Alaskan Arctic. In D.W. Norton, editor. Research advances on anadromous fish in arctic Alaska and Canada. Biological papers of the University of Alaska Number 24:27-54.

McCart, P. 1980. A review of the systematics and ecology of Arctic char, Salvelinus alpinus, in the western Arctic. Canadian Technical Report of Fisheries and Aquatic Science Number 935.

Underwood, T.J., J.A. Gordon, M.J. Millard, L.A. Thorpe, and B.M. Osborne. 1995. Characteristics of selected fish populations of Arctic National Wildlife Refuge coastal waters, final report, 1988-1991. U.S. Fish and Wildlife Service, Fairbanks Fishery Resource Office, Alaska Fisheries Technical Report Number 28, Fairbanks, Alaska.

Wiswar, D.W. 1992. Summer distribution of arctic fishes in the Okpilak, Akutoktak, Katakturuk, and Jago rivers, Arctic National Wildlife Refuge, Alaska, 1990. U.S. Fish and Wildlife Service, Alaska Fisheries Technical Report Number 17, Fairbanks, Alaska.

Wiswar, D.W. 1994. Summer Distribution of Arctic Fishes in the 1002 Area of the Arctic National Wildlife Refuge, Alaska, 1991 with emphasis on selected lakes, tundra streams, and the Sadlerochit River drainage. U.S. Fish and Wildlife Service, Alaska Fisheries Technical Report Number 27, Fairbanks, Alaska.