The variability in the features in some wild and fish hatchery populations of Pacific salmon

Abstract

The viability of some Pacific salmon bred at fish hatcheries is known to be considerably lower than that of the natural populations. It is interesting to compare some biological impotent features in several populations of Primorsky Region, Sakhalin Island and Kamchatka. The paper presents studies of specimens of natural and fish hatchery populations of chum salmon Onchorhynchus keta, chinook salmon O. tshawytscha and pink salmon O. gorbuscha. The material for exploration was obtained at Barabashevsky fish hatchery (Primorsky Region), Sokolovsky fish hatchery (Sakhalin Island) and Malkinskiy hatchery (Kamchatka), as well as from the Rivers Melkaya and Tym' (Sakhalin Island) in 1988-1991. As a criterion of ontogenesis stability and significance of heredity for the formation of some characteristic features in the populations it was chosen the rate of fluctuating asymmetry (FA) of different features: number of pores of seismosensory channels, gill rakers, rays in pectoral fins and ventral fins, spots along the side line. The indices of viability, sex ratio, dynamics of change in size and weight were studied too. The rate of FA in wild populations was lower than in fish hatchery populations. The variability in the above-mentioned features of the observed populations is described. The most degree of variability was estimated at the Sokolovsky fish hatchery. We established that the fish individual of each population was characterized by certain typical indices of the features and FA of the coupled features.