Michigan Department of Natural Resources
Fisheries Research Report No. 1861, 1978
A Three-Year-Old Pink Salmon from Lake Superior
Wilbert C. Wagner
Introduction-In North America, nearly all pink salmon (Oncorhynchus gorbuscha)
mature in their second year of life (Anas 1959; Bilton and Ricker 1965). In the literature
I could find only two instances where the life cycle of North American pink salmon was not 2
years. Anas (1959) reported a 3-year-old female collected from the Skeena River, British Columbia.
Turner and Bilton (1968) reported an immature male in its second year caught by salmon longlines
in the Gulf of Alaska on 7 December 1966. Although this fish was not yet 3 years old, they presumed
that it would mature in its third year or later. Pink salmon were introduced into Lake
Superior in 1956 and all were believed to have a 2-year life cycle and spawn only in odd-
numbered years (Collins 1975; Wagner and Stauffer 1975). In the present report, I
describe the occurence of a 3-year-old pink salmon in Lake Superior.
On 29 October 1976, an angler caught an unidentified salmonid from the Chocolay River, a
Michigan tributary of central Lake Superior. James Peck, Paul Hannuksela, and I
tentatively indentified it as a pink salmon. The identification was subsequently
verified by Paul Hannuksela from keys given by Carl et al. (1967). The primary
identifying characteristics were the large oval spots on the back and caudal fin and
the small scales (187 and 192 in the first row above the lateral line). The pink
salmon was a spent female, 496 mm long (TL) and weighed 970 g. This fish was unique
because pink salmon in the Great Lakes usually spawn only during odd years in September
(Wagner and Stauffer 1975).