Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8237
Title: Microsatellite DNA analysis of Pacific hake Merluccius productus population structure in the Salish Sea
Author: Eric Iwamoto, A. Elz, Francisco J. García-De León, Claudia A. Silva-Segundo, Michael J. Ford, Wayne A. Palsson, Rick G. Gustafson
Publication Year: 2015
Journal: ICES Journal of Marine Science
Keywords: Genetics

This study presents the first microsatellite DNA study of population structure of Pacific hake, Merluccius productus (also known as Pacific whiting) within the Salish Sea, which has been identified as a distinct population segment (DPS) under the U.S. Endangered Species Act (ESA) and is currently listed as a federal Species of Concern.  In contrast, a separate coastal stock component of Pacific hake represents the most abundant commercial groundfish species on the U.S. West Coast.  We surveyed variation at 10 microsatellite DNA loci in a total of 655 individuals from three Salish Sea locations (Port Susan and Dabob Bay in Washington and south-central Strait of Georgia in British Columbia), three coastal locations (two off southern California and one in the Gulf of Alaska), and the upper Gulf of California, México.  No significant differences were detected among temporal samples from both Port Susan and Strait of Georgia locations.  Multilocus measures of population subdivision between coastal and Salish Sea populations (all pairwise FST ≥ 0.03) and between Port Susan and Strait of Georgia populations (FST ≥ 0.01) suggest a moderate degree of demographic isolation among these spawning populations.  No significant genetic differences were found among the three coastal Pacific hake samples; however, Pacific hake from the Gulf of California were significantly differentiated from both coastal (FST > 0.05) and Salish Sea (FST ≥ 0.03) Pacific hake.  Correlations between genetic and geographic distance showed that Pacific hake display a very strong isolation by distance signal, both over the whole study area (~4,500 km; r2 = 0.94) and within the Salish Sea (~280 km; r2 = 0.72). This study suggests that Port Susan and Strait of Georgia populations are to some extent demographically isolated from each other.

Theme: Recovery and rebuilding of marine and coastal species
Foci: Characterize the population biology of species, and develop and improve methods for predicting the status of populations.