DOI: 10.5061/dryad.4kp00
title: Data from: Eliminating variation in age at spawning leads to genetic divergence within a single salmon population

description: Most coho salmon Oncorhynchus kisutch in Washington state spawn at 3 y of
 age, creating the potential for three temporal populations or “broodlines”
 at each spawning site. This is generally prevented by a portion of males
 in each site that mature and reproduce at 2 y of age, resulting in
 population structure in which the geographic component is stronger than
 the temporal component. The Quilcene National Fish Hatchery, located on
 Big Quilcene River in the Hood Canal region of Washington state, selected
 against late returning coho salmon by excluding all but the earliest
 returning fish from its broodstock for an unknown number of generations,
 and restricted gene flow among broodlines by excluding 2-y-old males for
 27 generations. The resulting hatchery population exhibited three distinct
 broodlines that returned in alternating years: an “early” broodline that
 arrived 1 mo before the wild fish, a “late” broodline that arrived at the
 same time as the wild fish, and a “middle” broodline that arrived in
 between these two broodlines. We evaluated temporal and geographic
 components of population genetic structure in coho salmon from the
 Quilcene National Fish Hatchery and nine other sites from Puget Sound and
 the Strait of Juan de Fuca using 10 microsatellite loci. Genetic diversity
 at the Quilcene National Fish Hatchery was lowest in the early broodline
 and highest in the late broodline. Divergence among broodlines was
 generally much lower than divergence among sites, rendering the term
 broodline irrelevant for most sites. Divergence among broodlines at the
 Quilcene National Fish Hatchery, however was greater than that observed at
 any other site, and was also greater than that observed between any of the
 sites. This apparent reversal of the relative magnitudes of temporal and
 geographic components for this species emphasizes the importance of
 variable age-at-maturity in shaping population genetic structure.
description: Appendix
 1Genotype data for ten
 microsatellite loci in collections of coho salmon Oncorhynchus kisutch
 from Quilcene Hatchery and other sites in Puget Sound and the Strait of
 Juan de Fuca taken between 1997 and 2011.Figure
 A1Numbers of inferred
 populations (K) in samples of Quilcene Hatchery coho salmon Oncorhynchus
 kisutch based on Bayesian clustering analysis. Collections were taken
 between 1999 and 2011. Both a) mean (+/- standard deviation) Ln of the
 probability of the data (X), and b) K (rate of change in the log
 probability of data) are plotted for K = 1 to 8. These results suggest
 that our collections from Quilcene Hatchery represent three
 populations.Table
 A1Pairwise FST estimates
 for collections of coho salmon Oncorhynchus kisutch from Quilcene Hatchery
 and other sites in Puget Sound and the Strait of Juan de Fuca taken
 between 1997 and 2011. Values highlighted in grey were not statistically
 significant (alpha = 0.05) based on a permutation test.Reference
 A1.[USFWS] U.S. Fish &
 Wildlife Service. 2009. Quilcene, Quinault, and Makah National Fish
 Hatcheries: Assessments and Recommendations. Portland,
 Oregon.usfws_2009.pdfReference A2.[USFWS] U.S. Fish & Wildlife Service. 2011. Genetic profile for Quinault Hatchery coho salmon. Longview, Washington.usfws_2011.pdf