Deep secrets of even-year and odd-year pink salmon unveiled by genetics

A new analysis of DNA differences between populations of pink salmon in the North Pacific reveals some fascinating insights into how these populations first arose and how they are related. Pink salmon all come back to spawn exactly two years after their parents spawned, which means that pink salmon coming back in even years (2014, 2016, 2018, etc.) are distinct from those coming back in odd years (2013, 2015, 2017, etc.). The new analysis is the latest confirmation of the surprising result that even year salmon all across the North Pacific are more closely related to each other, than to odd year pink salmon spawning in the same rivers. In every region examined, the odd-year pink salmon were more genetically variable than the even-year salmon. The results suggest that the last glacial maximum separated pink salmon populations, with one group surviving in Asia and North Alaska, and another group extending from southcentral Alaska to Washington. The new paper was authored by SAFS MS student Carolyn Tarpey, SAFS postdoc Garrett McKinney, and SAFS professors James Seeb and Lisa Seeb, as part of an international collaboration, and was published in the Canadian Journal of Fisheries and Aquatic Sciences.

Sample locations of pink salmon used in the analysis.
Genetic relatedness between pink salmon populations, showing how the even year lineages are more closely related to each other, and the odd lineages to each other, than are even-year and odd-year pink salmon spawning in the same regions.
Back to Top