Recruitment of juvenile Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) in the Savannah, Ogeechee, and Satilla Rivers in Georgia

Atlantic sturgeon (Acip-enser oxyrinchus oxyrinchus) is a anad-romous fish found along the east coast of North America and is listed under the Endangered Species Act of the United States. Decades of overfishing and habitat degradation have caused range- wide population declines, and the population status of this species in many rivers is unclear. Quantifying annual recruitment is one way to assess the status of sturgeon populations, but such assessments are few. The objective of this study was to quantify recruit-ment of juvenile Atlantic sturgeon in the Savannah, Ogeechee, and Satilla Rivers in Georgia. Because we used identical methods in 3 rivers simultane-ously, we were able to directly compare recruitment among these populations with that of other populations observed in contemporaneous studies in other rivers. We conducted mark-recapture sampling during 2014-2017 and used Huggins closed population models to estimate annual recruitment. Because there are no historical data for compar-ison, we evaluated the 3 populations in terms of recruit abundance, varia-tion, and consistency. The Savannah River annually had relatively large numbers of recruits (639-937 individ-uals). Fewer recruits were produced in the Ogeechee (27-57 individuals) and Satilla (51-134 individuals) Riv-ers; recruitment occurred in only some years in those rivers. Populations that produce few recruits or do not have reg-ular recruitment may be experiencing bottlenecks preventing recovery.

Automated summary

This study aimed to quantify recruitment of juvenile Atlantic sturgeon in the Savannah, Ogeechee, and Satilla Rivers in Georgia to assess their population status. The results showed that the Savannah River had larger annual recruitment numbers (639-937 individuals), while fewer recruits were produced in the Ogeechee (27-57 individuals) and Satilla (51-134 individuals) Rivers, and recruitment occurred only in some years. Populations with low or irregular recruitment may be facing bottlenecks preventing their recovery.