Eavesdropping on Gulf of Maine Cetaceans in the Vicinity of Mount Desert Rock

• Main Author: Tremblay, Christopher James
• Format: Text
• Language: unknown
• Published: DigitalCommons@UMaine 2018
• Subjects: Whales; Acoustic monitoring; Life Sciences; Balaenoptera acutorostrata; Balaenoptera borealis; Balaenoptera physalus; baleen whale; Eubalaena glacialis
• Online Access: https://digitalcommons.library.umaine.edu/etd/3004; https://digitalcommons.library.umaine.edu/context/etd/article/4100/viewcontent/Tremblay_Thesis_FINAL_1.3.2019.pdf

Passive acoustic monitoring, the recording and analysis of biological sound, is a standard method of research into the distribution and behavior of cetaceans worldwide. Acoustic monitoring is reliant upon a thorough reference catalog of species vocalizations and an understanding of the temporal and geographic parameters in which vocalizations occur. This study combined a standard cetacean passive acoustic monitoring survey with a concurrent visual survey at a known baleen whale summer feeding ground to determine the annual species and vocal composition, compare species detection rates using each method, and identify and attribute novel vocalizations to species. The survey took place at the Mount Desert Rock marine research station, Gulf of Maine, from July to October 2015 and 2016. Visual and acoustic detections of fin (Balaenoptera physalus), minke (Balaenoptera acutorostrata), humpback (Megaptera Noavaeangliae), right (Eubalaena glacialis), and sei (Balaenoptera borealis) whales were assessed. Minke whales were the most frequently seen species (71% of days), followed by fin (51%), humpback (40%), and right (4%). Visual detections of minke and fin whales were more restricted by distance than humpbacks, and fin and humpbacks were sighted significantly more frequently in the northeast quadrant of the survey space, suggesting each species may have fine scale spatial preferences within the survey space. Stereotyped vocalizations of fin, minke, right, and sei whales were recorded, and automatic template detectors were used to evaluate daily and annual occurrence. Fin whales were the most frequently detected (31% of days), followed by minke (22%), right (15%), and sei (2%). Fin and minke whales vocalized primarily in evening and night-time hours, and right whales vocalized primarily during the day. Instances of multi-hour vocalization bouts were also recorded for fin, minke, and right whales. The number of days where each species was detected both visually and acoustically was low, meaning the use of only one method ...