Walleye pollock Theragra chalcogramma from the Navarin region and adjacent waters of the Bering sea: ecology, biology and stock structure

Abstract

Finding out the population structure of pollock is a complex procedure because of the species seasonal and ontogenetic migration intensity which undergoes significant interannual variations as dependent on the climate and ocean conditions, the abundance of population, and of the species in total. That is why, in order to obtain a comprehensive picture, the book reviews the results of a decade of integrated research (1996-2004) which included 26 cruises, 21 trawl surveys, 11 echointegration trawl surveys, 8 surveys of the juveniles and five ichthyoplankton surveys made in the northern, western and eastern parts of the Bering Sea where a novel approach developed by VNIRO was applied which involved serial repetition of surveys during a year. For the first time the results of such surveys made it possible to obtain information on the stock structure dynamics. The monograph reviews the organization of the Bering Sea pollock population using a virtually full set of approaches to the study of populations: genetic, ecological (biogeocenotic), morphological, biochemical, physiological, energy and ethological. The functional structure dynamics of the range between the 1970s and the present time was analyzed, as based on the own and published data.