Behaviour 2019
How do various anthropogenic stressors affect the long-term habitat use of bottlenose dolphins?  
Samantha Huron1, Dara Orbach1, Shawn McCracken1, William McGlaun2. 1Texas A&M University- Corpus Christi, Corpus Christi, Texas, United States; 2Texas Sealife Center, Corpus Christi, Texas, United States

Noise, pollution, shipping traffic, and habitat loss increasingly affect marine biota. In heavily industrialized coastal areas, such as the South Texas Coastal Bend, the impacts of dredging on marine life are largely unknown. Common bottlenose dolphins (Tursiops truncatus) are a resident bioindicator species that can be used to infer ecosystem health. Photo-identification and geospatial data (2014 – 2020) were combined to assess if dolphins exhibited preferences for areas nearby petrochemical processing plants, wastewater treatment plants, and recently dredged channels. The dorsal fins of dolphins were photographed during boat-based surveys to distinguish individuals based on natural markings. Dolphin sighting locations and anthropogenic stressors were mapped in ArcGIS Pro. Dolphins exhibited preferred habitats, as >90% of sightings occurred in concentrated areas, particularly along newly dredged channels. Sightings frequently coincided with areas scheduled to be dredged imminently, but not near wastewater treatment or petrochemical plants. Monitoring of preferred habitats is essential to determine the impacts of dredging on dolphins and to mitigate potential harm.