Age, Food, and Migration of Dolly Varden Smolts in Southeastern Alaska

Abstract

Dolly Varden (Salvelinus malma) smolts were enumerated and sampled in 1967, 1968, and 1969 at Hood Bay Creek, a nonlake system on Admiralty Island, and in 1962, 1963, and 1964 at Eva Lake, on Baranof Island.Dolly Varden smolts left Hood Bay Creek from early May to late June and from early September to mid-November. At Eva Lake, a smolt migration occurred in May and June but not during the fall. Most of the smolts at Hood Bay Creek belonged to age-groups II, III, and IV and at Eva Lake to age-groups III and IV. Smolts from the two systems were similar in size, varying from 100 to 180 mm in fork length, with annual mean lengths ranging from 134 to 136 mm.Insects and fry of chum (Oncorhynchus keta) and pink salmon (O. gorbuscha) were the principal food items of Dolly Varden and coho salmon (O. kisutch) smolts sampled at the Hood Bay Creek weir in May and June. Dolly Varden smolts leaving Hood Bay Creek in the fall fed primarily on salmon eggs, whereas insects were the principal food items of smolts sampled at the Eva Lake weir.Suggestions for management of Dolly Varden are given. The number of eggs, fry, or smolts necessary to maintain a given run of Dolly Varden indicates a high return from smolts and a low return from eggs or fry. Transplanting smolts from one system to another to establish or enhance a population in a depleted system is suggested.