Abstract
Coastal waters are increasingly exposed to anthropogenic pressures, resulting in the degradation of critical habitats that shape the distribution of marine predators. This study used photo-identification data to define drivers of common bottlenose dolphin habitat selection in Mobile Bay and Perdido Bay, two urbanized estuaries in southern USA. Dolphins exhibited distinct seasonal habitat selection between estuaries. In Mobile Bay, dolphin occurrence decreased with water temperature and increase with dissolved oxygen during winter, and dolphins were more frequently observed closer to shore, near a key confluence point (Mobile Bay Pass) and in deeper water near ship channels in summer. In Perdido Bay, dolphin occurrence increased with pH and dissolved oxygen in winter, while in summer, dolphin occurrence increased in deeper waters, near ship channels and closer to gillnet exclusion zones. Across both systems, dolphins occurred in moderate-to-high salinity waters but also used very low salinity areas. Our results indicate a seasonal transition from physiochemical drivers in winter to structural and habitat-related factors in summer and suggest that ship channels may function as salinity refuges and prey hotspots, due to water stratification and higher prey availability. This work highlights dolphins’ adjustment to local conditions within dynamic estuarine environments under natural and anthropogenic influences.
Acknowledgements
We would like to thank all the staff and students who assisted, whether by skippering the research vessels or collecting data during the boat surveys, including Dr. Jennifer Bloodgood, Dr. Ania Brown, Lauren Clance, Christina Clark, Sophia Corde, Dr. Haley Gancel, Joe Hansen, Elizabeth Hieb, Dr. Matthew Hodanbosi, Tori McMahon, Biz Nasharr, Emily Pepple, Mackenzie Russell, and Jessica Veo from DISL; Amy Brossard, Joe Contillo, Laura Dias, Annie Gorgone, Michael Hendon, Lyndsey Howell, and Jesse Wicker from NOAA. Finally, we would like to dedicate this research to our friend and colleague, Kevin Barry, who was an integral member of our core team and sadly passed away in 2023. His friendship, positivity, professionalism, and passion for marine ecology continue to be deeply missed.
Funding
This research was funded by Deepwater Horizon natural resource damage settlement funds provided by the Alabama Trustee Implementation Group with funding support and participation of Alabama Department of Conservation and Natural Resources (ADCNR).
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This research was conducted under National Marine Fisheries Service (NMFS) Scientific Research Permit No. 23772 issued to Dauphin Island Sea Lab (DISL), and No. 21938 issued to SEFSC-NOAA. Research protocols used were approved by the Institutional Animal Care and Use Committee (IACUC) prior to data collection: NMFS Atlantic IACUC 2020-002.
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Bouveroux, T., Cloyed, C.S., Barry, K. et al. Spatial distribution and habitat selection of common bottlenose dolphins (Tursiops truncatus) within two estuaries in southern coastal USA.
Sci Rep (2026). https://doi.org/10.1038/s41598-026-52366-1
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DOI: https://doi.org/10.1038/s41598-026-52366-1
Keywords
- Anthropogenic factors
- Cetaceans
- Environmental drivers
- Environmental change
- Resource selection function models (RSF)
- Salinity
Source: Ecology - nature.com
