A Hypothesis of Alternation of Age of Return in Successive Generations of Skeena River Sockeye Salmon (Oncorhynchus nerka)

Abstract

Egg weight of Scully Creek and Lower Babine River sockeye salmon (Oncorhynchus nerka) was positively correlated with length and, usually, age of the female parent. Egg weight was positively correlated with initial size and subsequent growth of juveniles, at least up to 3 months of age. Examination of scales indicated juvenile growth in the lake and ocean was inversely related to age at maturity. Hence it was hypothesized that the larger age 1.3 sockeye spawners tend to produce progeny that mature as smaller age 1.2 fish, which in turn give rise to progeny that mature as larger age 1.3 fish, and so on; an alternation in age of return of successive generations occurs.