Gulf of Alaska | Fishes and Fish Habitats
Chromosomal inversions and selection influence population structure and phenotypic differentiation of Pacific herring Presenter: Eleni Petrou , epetrou@usgs.gov, USGS Alaska Science Center Lorenz Hauser , lhauser@uw.edu Kyle Rosendale , kyle.rosendale@sitkatribe-nsn.gov Todd Sandell , Todd.Sandell@dfw.wa.gov Jeff Feldpausch , jeff.feldpausch@sitkatribe-nsn.gov Leigh Engel , engell@hawaii.edu Madonna Moss , mmoss@uoregon.edu Pacific herring ( Clupea pallasii ) is a culturally, ecologically, and economically important species in North Pacific ecosystems. In recent decades, the abundance and the spatiotemporal distribution of herring spawning has contracted in some geographic regions, leading to declining subsistence harvests and concern over the alignment of fisheries management areas with genetic population structure. We investigated whether spatially and phenologically distinct spawning aggregations of Pacific herring are genetically differentiated using low-coverage whole genome sequencing of 556 herring collected from twelve spawning sites in Southeast Alaska and Puget Sound. Using genotype likelihoods estimated for over 600,000 loci, we compared herring from different sites that spawn in three distinct seasons (Jan/Feb, March/April, May/June). Our analyses found that the three spawning groups are genetically differentiated but through contrasting mechanisms. March/April spawners were differentiated from other spawn groups primarily at several large chromosome inversions. In contrast, winter (Jan/Feb) and late-spring (May/June) spawners had very similar inversion frequencies but showed selective differentiation in several narrow sections of the genome that were independent of inversions. These results indicated that structural genomic variants drive some, but not all, of the genetic differences between the different spawning phenotypes. Within spawning phenotypes, shallow isolation-by-distance was detected, suggesting weak spatial structuring along the northeast Pacific coast. Outside of the spawning season, the distribution and vulnerability of these distinct populations to environmental perturbations and harvest pressure remains unknown and is a critical knowledge gap for fisheries management.
Alaska Marine Science Symposium 2023 181
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