Abundance Dynamics of Pink Salmon, Oncorhynchus gorbuscha, as a Structured Process Determined by Many Factors

Despite the fact that pink salmon is a fish species with a short-cycle life span, its stock abundance dynamics exhibit features typical of common pelagic fish species with an average life-cycle duration. Interchanging periods of high and low pink salmon abundance levels relate to positive and negative stock abundance trends inherent for major regional groups, Asian and American parts of aggregate stocks, and for pink salmon species as a whole (Radchenko et al. 2007). This feature of pink salmon abundance dynamics is determined by structural organization of the species and its populations. Major regional groups of pink salmon are divided into temporally isolated evenand odd-year populations. The life cycle of pink salmon can be conditionally divided into two periods: freshwater (including spawning, embryonic, and downstream migration phases) and marine (including inshore, marine waters in marginal seas, and oceanic phases). The phases repeat in reverse order until fish return from the sea and reach their spawning grounds. Most stocks, in turn, are separated by paired seasonal races with distinct morphological characteristics and spawning areas within river basins.