Times of Annulus Formation on Scales of Sockeye, Pink, and Chum Salmon in the Gulf of Alaska

Abstract

On scales of pink (Oncorhynchus gorbuscha), chum (O. keta), and possibly sockeye (O. nerka) salmon caught by Canadian research vessels throughout the Gulf of Alaska at various times of the year, the annual ring began to form sometime between early November and January. Many of the sockeye and pink salmon had completed the annulus sometime in December or January, whereas the chum salmon completed their's later, in February or March. For both sockeye and chum salmon, scales of younger fish tended to commence new growth at an earlier date than did those of older fish.