Spatiotemporal distribution of dolphins within the Gulf of Maine

Dolphin presence in the Gulf of Maine (GOM) has been previously classified as uniform across space and time, with little specification beyond this general distinction. With wind energy development planned for the GOM, a deeper understanding of the spatiotemporal distribution of dolphins is imperative. From 2020 to 2023, acoustic recorders (AMARs, Soundtraps, and F-PODs) were deployed in 30 sites throughout the GOM. This study analyzed SoundTrap data for dolphin whistles on an hourly time scale, using the PAMGuard whistle and moan detector along with custom python-based detection-viewing software, Soundscope, for validation. SoundTrap data detections were then compared to dolphin detections from other passive acoustic recorders in the region. Dolphins were detected at all recording locations with varying presence based on region and time of year. Dolphins were present year-round in offshore GOM, while seasonally present in inshore GOM. For the inshore GOM, presence varied seasonally by location. Along the Southern coastal shelf, dolphin presence peaked in spring and fall, while along the northern coastal shelf, dolphin presence peaked from fall to winter. These results expand on current knowledge of dolphin habitat use and can be used to guide wind energy plans for the lowest impact.