Estimating juvenile Gulf Sturgeon survival in the Choctawhatchee River and estuary using telemetry and multistate mark–recapture

ABSTRACT Objective Understanding the survival and movement of juvenile Gulf Sturgeon Acipenser desotoi is critical for improving recovery efforts under the U.S. Endangered Species Act. The river and estuary portions of the Choctawhatchee River watershed, a key part of the species’ range, provide required habitat used by juvenile life stages. While the ecology and demographics of adult Gulf Sturgeon are well studied, similar information on juveniles remains limited. Methods We used acoustic telemetry data collected during 2020–2022 and applied multistate capture–recapture models to these data to estimate seasonal survival (Φ), transition probabilities between riverine and estuarine habitats (Ψ), and detection probabilities (p) for juvenile Gulf Sturgeon. Tagged individuals (350–1,150 mm FL) were monitored using a fixed array of autonomous receivers within the Choctawhatchee River watershed, with emphasis on estuary and river habitats. Results The top-ranked statistical model indicated that survival varied by season and habitat type but was consistent across years and among our assumed age-classes based on length at capture. Transition probabilities revealed seasonal patterns, with movements from river to estuary peaking in winter (Ψ = 0.41) and from estuary to river peaking in spring (Ψ = 0.58). Detection probabilities also varied seasonally, reflecting differences in occupancy across habitats. These results suggest that Gulf Sturgeon ≥350 mm FL have surpassed an early life high-mortality phase characterized by Type III survivorship. Conclusions These findings improve our understanding of survival rates and seasonal habitat use in a critical life stage of Gulf Sturgeon. Transition probabilities can inform risk exposure timing to stressors such as dredging or infrastructure replacement. The consistency in juvenile survival across sizes suggests that the greatest recruitment compensatory potential is in size-classes ≤350 mm FL, which can inform ongoing monitoring and recovery planning for this threatened species.