Genetic Population Assignments of Atlantic Sturgeon Provided to National Marine Fisheries Service, 2022

Abstract

Acipenser oxyrinchus oxyrinchus (Atlantic sturgeon) were once abundant and supported large-scale fisheries throughout much of the east coast of the United States. However, historic overharvest and habitat loss resulted in dramatic declines in abundance and eventual listing under the Endangered Species Act of the United States. As part of this listing, Atlantic sturgeon populations were divided into five distinct population segments (DPSs), with many management activities occurring at the level of the DPS. However, because subadult and adult Atlantic sturgeon can make large, coast-wide migrations and often mix extensively with individuals from other populations, individuals may be exposed to conservation threats away from their natal river or DPS, ultimately making it difficult to determine the appropriate spatial scale for management activities. To help address this uncertainty, the U.S. Geological Survey performed genetic assignment tests to determine the natal origin of 329 Atlantic sturgeon that were encountered as mortalities or taken during permitted activities in 2021. Overall, most individuals assigned to the Hudson River population, with additional major contributions from the James River Fall and Delaware River populations. However, a sizeable proportion of individuals were assigned to more distantly located populations in the southeastern United States. These results highlight the prevalence of long-distance movements in Atlantic sturgeon and underscore that populations may be vulnerable to threats far from their natal rivers.