Conservation Genetics of Atlantic Sturgeon Active

Sources/Usage: Public Domain.

Following decades of declines, Atlantic Sturgeon were listed under the Endangered Species Act in 2012. Based on available genetic information, the species was broken into five Distinct Population Segments (DPSs). The DPSs are predicated on geographic clusters of their spawning rivers delineated by zones of genetic discontinuity. However, Atlantic Sturgeon move extensively in coastal waters, and there is a critical need to be able to distinguish among management units when individuals are encountered away from natal areas. This information is vital for gaining insights into the ecology of Atlantic Sturgeon, understanding the impacts of human activities on specific stocks, and tracking recovery progress. Moreover, federal regulations require certain Atlantic Sturgeon captured during research activities or collected as incidental take to be assigned to a DPS so that take can be appropriately partitioned among management units (under the Endangered Species Act, each DPS is essentially treated as a unique species, so knowing which DPS is affected by an action is critical). In addition, the recent rediscovery of populations of Atlantic Sturgeon that were formerly thought to be extirpated necessitates that additional population genetic studies be conducted to place these populations into context and incorporated into the genetic baseline, as well as ensure appropriate management strategies can be developed.

In marine and estuarine environments, Atlantic Sturgeon often form mixed-stock assemblages where they are subject to fisheries bycatch and other threats to their recovery. Determination of the lineage or river-of-origin among individuals in coastal aggregations has been identified as a high priority research objective. EESC biologists are conducting individual based assignment testing to resolve the composition of mixed stock aggregations of Atlantic Sturgeon found at key sites along the Atlantic Coast to inform management decisions. EESC biologists are also comparing the genetics of newly rediscovered populations of Atlantic sturgeon to previously documented populations, to evaluate if they fit within the genetic clusters that are the basis for the current DPS management system. These studies provide valuable information on the DPS of origin for Atlantic Sturgeon encountered during permitted activities.

There is limited knowledge of the status of many Atlantic sturgeon populations. EESC are using genetics in several ways to help characterize and enumerate spawning runs in several rivers. In a recent publication, EESC biologists used pedigree-reconstruction to infer the number of adult sturgeon which spawn annually in the Delaware River. In addition, EESC provides technical expertise and genetic data to support the ASMFC stock assessment process for Atlantic Sturgeon.

Finally, the migratory corridors used by Atlantic Sturgeon are not well understood, and additional information is needed to understand when and where specific populations are found so that the impacts of anthropogenic activities can be predicted. EESC biologists are working to combine telemetry and genetic data to resolve the coastwide migratory corridors of Atlantic Sturgeon populations. This approach is tractable through collaborations with numerous outside agencies and the use of our genetic baseline for assignment testing. The USGS EESC is well positioned to conduct this research, based on our extensive network of partners in the sturgeon research community, a microsatellite genetic baseline that we have developed for assignment testing, and our stewardship of the Atlantic Coast Sturgeon Tissue Research Repository.