Being Consistent: Spatial Estuarine Habitat Use Seasonally and Annually during Emigration/Immigration of a Western Population of Gulf Sturgeon Acipenser oxyrinchus desotoi

Gulf Sturgeon Acipenser oxyrinchus desotoi, occupancy patterns varied spatially, seasonally, and annually based on acoustically-tagged fish in the Pascagoula River estuary over a three year period (2010-13).  Juvenile estuarine occupancy was annually more variable but higher than sub-adults or adults.  Sturgeon of all size classes entered the acoustic array earlier when gage heights and discharges were high (2011, 2012) compared to lower levels (2010), which was 14-28 days earlier for adults and sub-adults but 12-17 days for juveniles. There were no differences in the occupancy patterns by year or season for adults or sub-adults (all p>0.255) or by year (p=0.642) for juvenile sturgeon, suggesting repeated annual patterns.  Juveniles occupied the West distributary more than the East distributary (p=0.003) and the River zone (p=0.016) of the acoustic array but River occupancy was greater than the East (p=0.012) zone; we also found similar patterns for sub-adults.  No year, season or zone patterns were identified for adult sturgeon, suggesting a travel corridor.  Adults appear to move quickly through the system during emigration (fall) and immigration (spring) compared to longer but more variable occupancy for juveniles and sub-adults.  Our long-term data supports the importance of habitat connectivity in the recovery of Gulf Sturgeon.