Some issues of dynamics for the herd of pink salmon Oncorhynchus gorbuscha in the Aniva Bay (Sakhalin Island)

Results of monitoring on the pink salmon spawning in the rivers of Aniva Bay (southern Sakhalin Island) in 1975–2004 are presented, including dynamics of the fish run to the coast and the number of spawners on the spawning grounds, biological parameters of the spawners, and quantitative accounts of the juveniles migrated downstream the monitored rivers. Based on these data, the total number of parent fish, juveniles, and returning adults are estimated for each year-class and the reproduction efficiency of pink salmon in the freshwater and marine periods of their life are calculated. Dynamics of pink salmon abundance in the Aniva Bay and dominance of the generative line of odd years were mostly determined by factors acting during the marine period of life, that’s why the number of returned adults depended more on the number of juveniles than on the number of producers on the spawning grounds.