On the Issue of Life Strategy Formation in Pacific Salmon of the Genus Oncorhynchus (Salmonidae)

Abstract

Data on life strategies of Pacific salmon of the genus Oncorhynchus are reviewed, and possible mechanisms of their realization in the ontogeny are discussed. Reproductive success and maintenance of intraspecific diversity are provided due to synchronization of maturity dates in the individuals with different life strategies. The following hypothesis is proposed. A complex of factors determining the ontogenetic vector of the individuals is not restricted by temperature, food availability, or accessibility of rearing areas. The key factors for realization of a certain life strategy are the presence of essential carotenoid pigment astaxanthin in rearing areas and physiological ability of the fish for its assimilation and accumulation. Relations between the life strategies in different species and populations of Pacific salmon and sex composition of individuals with different life strategies are mainly determined by astaxanthin availability.