Center for Marine Biodiversity and Conservation

This project focuses on genetic relatedness and population structure among Common Thresher sharks (Alopias vulpinas) found in Baja California, Mexico and California waters. It then addressed considerations for effective bilateral management between the two countries where they are commercially and recreational caught. The US and Mexico manage their Common Thresher shark fisheries independently of each other and there are currently no binational fisheries management plans between the US and Mexico. While important for managing fish populations that span multiple jurisdictions, bilateral fisheries agreements are uncommon. Further, there is a particular need for more information of shark populations around the world to inform management efforts. Although tagging studies provide important information, more research into population structure is needed for many shark species, as well as insights into population genetic health. With the goal of learning more about NEP Common Thresher sharks and their management, this project addresses four research questions: (1) Do these sharks comprise a single, panmictic population? (2) What can genetic identification of sibling relationships tell us about the population(s) response to the international border? (3) What is the effective population size (Ne) for this/these population(s)? (4) What is known about the status of this population; and what are perspectives on efficacy of current management?