Comparison of Gulf sturgeon Acipenser desotoi use of Ship Island, Mississippi, USA, before and after restoration of barrier island habitats

Barrier islands in the Mississippi Sound are vital to various species, including federally threatened Gulf sturgeon (GS). Hurricane-associated island degradation of Ship Island prompted a large-scale restoration project that was completed between 2017 and 2020, in which an island pass, Camille Cut (CC), was filled. Waters surrounding these barrier islands had previously been identified as critical foraging habitat for GS, particularly in island passes, thus formally requiring assessment of the restoration project on GS. Prior to the restoration project, a study was conducted from 2011-2015 using an acoustic array of 21-39 receivers to assess occupancy patterns of GS. After the habitat restoration completion in 2020, a post-restoration acoustic array was deployed from 2021-2023 consisting of an additional 32-34 receivers. In the pre-restoration study, subadult and adult GS from river populations west (WPU) and east (EPU) of Mobile Bay, Alabama, USA, were found to occupy an island pass—Dog Keys Pass—more than CC. The post-restoration findings indicated increased use north of the former CC and decreased use of Dog Keys Pass, but habitat use was similar, as supported by community detection analyses. Pre-restoration network analyses indicated disjunct clustering of GS habitat use for individuals from both the WPU and EPU, and post-restoration data indicated cyclical movement patterns and mirrored available migration pathways given the change in island configuration. This study provides insight into the plasticity of large subadult and adult GS after a large-scale habitat restoration and further highlights the importance of long-term monitoring efforts.