Effective Size of the Early-Run Sockeye Salmon Oncorhynchus nerka Population of Lake Azabach’e, Kamchatka Peninsula Evaluation of the Effect of Interaction between Subpopulations within a Subdivided Population

Abstract

The effect of subdivision on the effective size ( N e ) of the early-run sockeye salmon Oncorhynchus nerka population of Lake Azabach'e (Kamchatka Peninsula) has been studied. The mode of this effect is determined by the relative productivity of the subpopulations and its magnitude, by the rate of individual migration among subpopulations and genetic differentiation. If the contributions of subpopulations (offspring numbers) are different, genetic differentiation can reduce the N e of the subdivided population. At equal subpopulation contributions, genetic differentiation always increases the N e of the subdivided population in comparison with a panmictic population. We have found that all sockeye salmon subpopulations of Azabach'e Lake produce equal offspring numbers contributing to the next generation. The genetic differentiation between sockeye salmon subpopulations is low, and the subdivision increases the N e of the early-run race with reference to the sum of the effective sizes of the subpopulations by as little as 2%. ANIMAL GENETICS

Pacific Salmon and the Coalescent Effective Population Size

“…A disproportionately large p 5 compared to p 4 would mean higher variance in reproductive success among age classes, as an individual in the fifth age class would contribute a disproportionately large number of offspring compared to an individual in the fourth age class. This is also in agreement with previous studies on sockeye salmon ( Oncorhyncus nerka ) and steelhead trout ( Oncorhyncus mykiss ) [52] , [53] , [54] . Similarly, these experimental studies suggested that variability in reproductive success is the main cause of low effective population size in these organisms using inbreeding effective population size.…”