Isolation by distance among California sea lion populations in Mexico: Redefining management stocks

M. González-Suárez, R. Flatz, D. Aurioles-Gamboa, P. W. Hedrick, L. R. Gerber

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Understanding the spatial structure of a population is critical for effective assessment and management. However, direct observation of spatial dynamics is generally difficult, particularly for marine mammals. California sea lions (Zalophus californianus) are polygynous pinnipeds distributed along the Pacific coast of North America. The species' range has been subdivided into three management stocks based on differences in mitochondrial DNA, but to date no studies have considered nuclear genetic variation, and thus we lack a comprehensive understanding of gene flow patterns among sea lion colonies. In light of recent population declines in the Gulf of California, Mexico, it is important to understand spatial structure to determine if declining sea lion colonies are genetically isolated from others. To define population subdivision and identify sex biases in gene flow, we analysed a 355-bp sequence of the mitochondrial DNA control region and 10 polymorphic microsatellite loci from 355 tissue samples collected from six colonies distributed along Mexican waters. Using a novel approach to estimate sex biases in gene flow, we found that male sea lions disperse on average 6.75 times more frequently than females. Analyses of population subdivision strongly suggest a pattern of isolation by distance among colonies and challenge current stock definitions. Based on these results, we propose an alternative classification that identifies three Mexican management units: Upper Gulf of California, Southern Baja Peninsula, and Upper Pacific Coast of Baja. This revised classification should be considered in future assessment and management of California sea lion populations in Mexican waters. © 2009 Blackwell Publishing Ltd.
Original languageAmerican English
Pages (from-to)1088-1099
Number of pages978
JournalMolecular Ecology
DOIs
StatePublished - 1 Mar 2009
Externally publishedYes

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Sea Lions
pinniped
Mexico
Otariidae
gene flow
Gene Flow
Gulf of California
founder effect
Population
Sexism
mitochondrial DNA
Mitochondrial DNA
coasts
gender
marine mammals
Pinnipedia
Gulf of Mexico
population structure
Water
coast

Cite this

González-Suárez, M. ; Flatz, R. ; Aurioles-Gamboa, D. ; Hedrick, P. W. ; Gerber, L. R. / Isolation by distance among California sea lion populations in Mexico: Redefining management stocks. In: Molecular Ecology. 2009 ; pp. 1088-1099.
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Isolation by distance among California sea lion populations in Mexico: Redefining management stocks. / González-Suárez, M.; Flatz, R.; Aurioles-Gamboa, D.; Hedrick, P. W.; Gerber, L. R.

In: Molecular Ecology, 01.03.2009, p. 1088-1099.

Research output: Contribution to journalArticle

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