This project seeks to identify the population structure of the shortfin mako shark in the northeastern Pacific Ocean. To this end, the fellow and colleagues have developed a set of custom microsatellite markers and are now analyzing nearly a thousand mako skin samples, archived at NOAA’s Southwest Fisheries Science Center in La Jolla. This analysis will determine whether there is one large or many smaller mako shark populations in the region. This is of interest to managers, as the quota for the shark fishery (a secondary target of the swordfish gillnet fishery) is currently set under the assumption that the species exists as a single population and that because of this, the spatial distribution of fishing effort in federal waters is irrelevant. Besides addressing the validity of these assumptions, the fellow plans, in the final stage of the project, to build a conceptual framework for a population dynamics model.