Temporal and spatial patterns of Shortnose Sturgeon (Acipenser brevirostrum) and Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus) spawning migrations in the Altamaha River system, Georgia

Sturgeon species in the U.S. are endangered or threatened because of various anthropogenic factors, and the identification of critical habitat and spawning migrations are crucial to their management and protection. The objectives of this study were to document and describe seasonal spawning migrations of endangered Shortnose and Atlantic Sturgeon in the Altamaha River system, Georgia. Using passive acoustic telemetry, the movements of 40 adult Shortnose Sturgeon and 45 adult Atlantic Sturgeon were monitored from April 2011 to March 2014. Upstream movements to suspected spawning habitat occurred during winter for Shortnose sturgeon and corresponded with changes in water temperature and discharge. Atlantic Sturgeon used spring two-step and fall one-step migrations, arriving at suspected spawning habitat in the fall as river temperatures dropped. These findings illustrate clinal variations in the life history of both species and highlight the need to manage sturgeon as distinct population segments with regionally specific recovery goals.