A Tale from Scales: Can We Learn Anything from Reading Fish Scales about the Effects of Climate Change?

Scales from sockeye salmon (Oncorhynchus nerka) caught in the Lower Columbia River commercial fishery in 1924 were analyzed for genetic variation in an effort to reconstruct the historical population structure of the run.  Archival scales from 603 fish, sampled from May to July 1924, were analyzed for genetic variability at 12 microsatellite loci, and compared to 17 present-day O. nerka populations—exhibiting either anadromous (sockeye salmon) or nonanadromous (kokanee) life histories—from throughout the Columbia River Basin, including areas upstream of impassable dams built subsequent to 1924.

Statistical analysis identified three major genetic assemblages of sockeye salmon in the 1924 fishery. Two of these putative historical populations were found to be genetically similar to extant populations in the Okanogan and Wenatchee River Basins (pairwise F_ST = 0.0036 and 0.0030, respectively).  This speed presentation introduces using scales to age the fish in this study and will be accompanied by a poster.