Annual Movement Patterns of Roanoke River Atlantic Sturgeon, Including Inter-Dps Marine Movements and Spawning Periodicity

Restoration of the endangered Atlantic Sturgeon Acipenser oxyrinchus depends on a solid foundation of biological data. For Roanoke River, North Carolina Atlantic Sturgeon there are questions regarding annual migration patterns, including spawning timing and marine movements. Six adult Atlantic Sturgeon (presumably males) from the Roanoke River were implanted with acoustic telemetry tags from 2010-2012.  These sturgeon were monitored through a network of passive receivers in North Carolina and eight additional states.  A multi-state model was used to estimate movement probabilities among riverine, estuarine, and marine areas.  From September 2010 to June 2014, five of six Atlantic Sturgeon were detected in three different National Oceanic and Atmospheric Administration Distinct Population Segments.  Sturgeon were observed to either spend the entire year in marine waters or winter-spring in marine waters, summer in Albemarle Sound and fall in the Roanoke River, spawning.  Multi-state modeling suggested that movement probabilities were seasonably variable.  Annual estimated mortality during the study was low (~0.03) and detection probability >0.50 in most study areas. Tagged sturgeon spawned in consecutive years or with a year in between spawning events. Atlantic Sturgeon movement complexity and population mixing in marine waters add to the potential difficulty in managing the recovery of this species.