Identification Of Critical Habitat and Spawning Migrations Of Shortnose Sturgeon Acipenser Brevirostrum In The Altamaha River System, Georgia

Spawning populations of shortnose sturgeon (Acipenser brevirostrum, Acipenseridae) have declined or been extirpated, particularly in rivers along the periphery of their range. Understanding the spatial and temporal dynamics of spawning migrations within natal rivers is a critical information gap with regard to habitat protection and ultimately, species recovery. The objectives of our study were to document and describe seasonal distribution and spawning migrations of shortnose sturgeon in the Altamaha River, Georgia. Using passive acoustic telemetry, we monitored the movements of 40 adult shortnose sturgeon from April 2011 through March 2013. Telemetry data revealed that during much of the year, shortnose sturgeon resided within the tidally influenced portion of the river. Upstream movements to spawning habitat occurred during winter and early spring, with the majority of fish returning to the lower estuary by March. Unlike spawning migrations in some northern rivers, the pattern of movement observed in the Altamaha was a single step migration with no resting or staging period.  This study further illustrates the clinal variation in life history typical of the species that may have important implications on river-specific strategies to recover the species.