Origin and distribution of local sockeye salmon Oncorhynchus nerka stocks in the western part of the Bering Sea in August–October 2006

Abstract

This study continues the identification monitoring of local sockeye salmon stocks in the Exclusive Economic Zone of Russia on the basis of scale criteria. This study was launched in 2002 as a part of BASIS (the Bering-Aleutian Salmon International Survey). Scale samples of immature sockeye salmon from the trawl catches of the R/V TINRO in the western Bering Sea in August–October 2006 were used for the analysis. The total number of these mixed samples was 1681 specimens for age definition and 1290 specimens for stock identification. The baseline samples (scales from 3162 specimens from Kamchatka, Chukotka and Alaska) were collected by the Kamchatka Research Institute of Fishery and Oceanography (KamchatNIRO), Chuckchee Branch of TINRO (ChukotTINRO), North-East Fishery Protection Service (Sevvostrybvod) and the Alaska Dept. of Fish and Game in the summer of 2006. The results of the analysis indicate the dominant role of the Bristol Bay complex of stocks in the formation of sockeye salmon stocks in the western Bering Sea for the period of the survey: their share was estimated as 55.3% or 88.18 million individuals The most frequent among the Asian stocks were the fishes from the Kamchatka (15.0% or 23.85 million individuals) and Ozernaya Rivers (14.5% or 23.07 million individuals). The summary contribution of minor stocks from north-eastern Kamchatka and Chukotka was also high (11.7% or 18.64 million individuals). The contribution of West Kamchatkan minor stocks was low (3.5% or 5.61 million individuals).