Investigation of fine spatial scale population genetic structure in two Alaskan salmonids.

Fidelity to natal habitat influences fine spatial scale genetic population structure in salmonids. We analyzed genomic diversity of two species of Alaskan salmonids, coho salmon (Oncorhynchus kisutch) and Dolly Varden char (Salvenius malma) in Kenai Peninsula of south-central Alaska using Single Nucleotide Polymorphisms (SNPs). We examined SNPs for patterns of molecular diversity and divergence. Sample design compared within- and among-catchment genomic variation at first-order streams. Genomic diversity and divergence were spatially distributed unevenly across sites. Populations in adjacent habitats showed different patterns of genetic migration. Our results suggest first order streams support locally diverged populations in coho salmon but not in Dolly Varden char and that multiple drainages may house metapopulations. This could result from interaction between ecological selection and philopatry. Conservation considering species-specific distribution of genetic diversity may avoid omission of crucial diversity and improve the capacity of populations to adapt to future conditions.