Genetic Analysis Reveals Restricted Dispersal of Northern Rockfish along the Continental Margin of the Bering Sea and Aleutian Islands

Abstract

The effective conservation and management of a species require knowledge of its population structure and life history. Fish that are mobile, long-lived, and abundant and that have pelagic larvae are often presumed to disperse over large geographic areas. However, if the individuals of such a species have limited dispersal, spatial scale must be considered when developing management plans. The economically and ecologically important northern rockfish Sebastes polyspinis, which is most abundant along the continental margin of the Aleutian Islands, has the potential to disperse widely during its life. The population genetic structure of a species provides a window into its demographic structure. Consequently, the variation at 11 microsatellite loci was used to characterize the geographic structure and connectivity of northern rockfish collected in 2004 along the continental margin of the Bering Sea slope and the Aleutian Islands. Significant genetic structure (F _ST = 0.0017) was detected, and a significant isolation-by-distance relationship indicated that there is limited lifetime dispersal (on the order of 100–200 km), which is much smaller than the scales used for sampling and management. In addition, the genetic divergence along the area sampled suggests decreased gene flow at Amchitka Pass and between the eastern Bering Sea and eastern Aleutian Islands.

Received February 9, 2011; accepted July 18, 2011

ACKNOWLEDGMENTS

We are indebted to the staff of Alaska Fisheries Science Center's Resource Assessment and Conservation Engineering Division for collecting the genetic samples during the 2004 trawl surveys. This publication is the result in part of research sponsored by the Cooperative Institute for Arctic Research with funds from NOAA under cooperative agreement NA17RJ1224 with the University of Alaska. References to trade names do not imply endorsement by the National Marine Fisheries Service, NOAA. The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the National Marine Fisheries Service.