Sizeable Insights Gained By Tracking Tiny Pacific Lamprey Larvae Using Parentage

New genetic tools have allowed species identification, recapture identification, and aging of larval and juvenile Pacific lamprey, which are especially challenging to study due to their diminutive size. These abilities are necessary for monitoring success of conservation strategies such as translocation, i.e., human-mediated transfers of Pacific lamprey from areas of moderate abundance to recipient sites of low abundance. Recapture identification is performed through parentage assignment. Integration of parentage analysis with translocation efforts in the interior of the Columbia River has made it possible to achieve nearly 100% sampling of the potential spawners for a large number of sites in any given year. Assigned offspring can be effectively aged by assuming the year their parents were translocated is the year they were spawned. Further, growth rate and distance traveled by these offspring can be estimated if we obtain size data at capture and assume their parents’ release site equates to the offspring’s natal site. We discuss some surprising biological insights related to mating biology, life stage transformation and migration timing, and the fitness implications of adult body size that we have learned by applying these genetic tools within the interior Columbia River.