Presentation Abstract

There is growing recognition that maintaining diversity in life history traits contributes to the sustainable management of wild populations. One important life history characteristic is reproductive phenology, and it has been shown that differences in the timing of reproduction can act as a barrier to gene flow between populations. If the difference in reproductive timing determines the level of connectivity, one would expect that genetic differentiation between populations would increase as a function of difference in reproductive date. This pattern, known as “isolation by time” (IBT), has been observed in wild populations of salmonids containing early and late runs. Pacific herring in the Salish Sea also exhibit a wide diversity of spawn times; some populations start reproducing as early as January and reproductive activity in the region continues through May. Here, we test whether these temporal differences in reproduction influence the genetic population structure of herring. We collected adult herring from seven different locations in the Salish Sea during active spawning events (N = 48 per site). Samples were sequenced using a restriction site-associated (RAD) approach and approximately 3,000 polymorphic loci were genotyped in each sample. We found a positive correlation between genetic differentiation and difference in spawn date, with evidence of migration between populations with similar spawn timing. Several loci exhibited exceptionally steep gradients in allele frequencies, including one locus linked to the photoperiodic regulation of reproduction. Our discovery of IBT in Pacific herring support the adaptive significance of spawn timing and underscore the importance of conserving spawning time diversity in Puget Sound herring.

Session Title

Advances in the Understanding of Drivers of Change and Potential Conservation Actions for Pacific Herring in the Salish Sea

Keywords

Genetics, Pacific herring, Dispersal

Conference Track

SSE11: Species and Food Webs

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE11-253

Start Date

6-4-2018 2:30 PM

End Date

6-4-2018 2:45 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 6th, 2:30 PM Apr 6th, 2:45 PM

The role of reproductive timing as a driver of genetic differentiation in populations of Pacific herring

There is growing recognition that maintaining diversity in life history traits contributes to the sustainable management of wild populations. One important life history characteristic is reproductive phenology, and it has been shown that differences in the timing of reproduction can act as a barrier to gene flow between populations. If the difference in reproductive timing determines the level of connectivity, one would expect that genetic differentiation between populations would increase as a function of difference in reproductive date. This pattern, known as “isolation by time” (IBT), has been observed in wild populations of salmonids containing early and late runs. Pacific herring in the Salish Sea also exhibit a wide diversity of spawn times; some populations start reproducing as early as January and reproductive activity in the region continues through May. Here, we test whether these temporal differences in reproduction influence the genetic population structure of herring. We collected adult herring from seven different locations in the Salish Sea during active spawning events (N = 48 per site). Samples were sequenced using a restriction site-associated (RAD) approach and approximately 3,000 polymorphic loci were genotyped in each sample. We found a positive correlation between genetic differentiation and difference in spawn date, with evidence of migration between populations with similar spawn timing. Several loci exhibited exceptionally steep gradients in allele frequencies, including one locus linked to the photoperiodic regulation of reproduction. Our discovery of IBT in Pacific herring support the adaptive significance of spawn timing and underscore the importance of conserving spawning time diversity in Puget Sound herring.