Using Passive Acoustic Data to Track Changes in Baleen Whale Distribution Throughout the Western North Atlantic Ocean

• Main Author: Davis, Genevieve E.
• Format: Text
• Language: unknown
• Published: ScholarWorks at UMass Boston 2020
• Subjects: Baleen Whales; Distribution; North Atlantic Right Whale; Occupancy Modeling; Passive Acoustic Monitoring; Seasonal Occurrence; Biology; Ecology and Evolutionary Biology; Greenland; baleen whale; baleen whales; North Atlantic; North Atlantic right whale
• Online Access: https://scholarworks.umb.edu/doctoral_dissertations/566; https://scholarworks.umb.edu/cgi/viewcontent.cgi?article=1565&context=doctoral_dissertations

Seven baleen whale species are found in the western North Atlantic Ocean, with limited information existing on the distribution and movement patterns for most. With climate driven changes in ocean temperature and circulation, there is mounting evidence of distributional shifts in many species, including marine mammals. This dissertation uses a decade of passive acoustic data to assess the presence of North Atlantic right (NARW), humpback, sei, fin and blue whales throughout the western North Atlantic. Data collected from 2004 to 2014 on 325 bottom-mounted recorders (35,600 days) were processed using automated detection software, and screened for each species’ presence. NARWs are one of the most endangered, but well-studied cetacean populations in the world. Starting in 2010, dedicated NARW visual survey efforts showed shifts in seasonal occurrence patterns. Acoustic recordings were used to examine whether similar shifts were observed, and if other baleen whale species demonstrated similar changes. All species were present throughout the dataset, from the southeast United States up to Greenland; humpback whales were also present in the Caribbean. Species occurred throughout all regions in the winter, suggesting that baleen whales are widely distributed during these months. All species showed significant changes in their acoustic occurrence before and after 2010. Lastly, a novel approach was used combining acoustic and visual datasets of NARWs from 2003 to 2016 to predict where NARWs occur. Management primarily focuses on visual data to determine NARW habitat. While NARW visual data dates back to the 1970s, data collection is limited by visibility, good weather, and survey range. PAM can provide continuous, year-round coverage of a broad area at comparably low costs, offering an excellent addition to visual sightings. This study uses an occupancy modeling approach to merge visual and acoustic data together. These results are a first attempt to fill in information gaps by using both data types together, providing a better understanding of important areas for a critically endangered species, and an alternative method for predicting long-term distribution changes.