UC San Diego

Nunatsiavut is a transition zone between Arctic and lower-latitude marine mammals in the southeastern Canadian Arctic. However, knowledge of baleen whale species and their habitat use in the Torngat Area of Interest (TAOI), northern Nunatsiavut, is limited. This study examined the seasonal presence and acoustic behavior of bowhead, fin, humpback, and sei whales in the TAOI through underwater sound recordings collected offshore from Saglek Bank between October 2022 and September 2023. Species-specific calls were identified by visually analyzing spectrograms every 30 minutes and included fin whale 20Hz downsweeps, sei whale 90Hz downsweeps, humpback whale song, and bowhead whale frequency modulated calls. A call parameter measurement tool was applied to measure signal characteristics, including contour creation and receive levels. The relationships between acoustic presence and environmental factors, such as sea ice concentration and solar elevation angle were examined. Fin whale 20Hz downsweeps were the most frequently detected calls, occurring from October to mid-January and again from June through the end of the deployment in September. Sei whale 90Hz downsweeps were detected during ice-free periods, from October to early January and again from late July to September. Humpback whale songs were only detected in the fall of 2022, during October and November, while bowhead whale frequency-modulated calls were recorded intermittently in the spring and summer, from late May to August. While we did not have enough acoustic detections to confidently observe if there was a diel calling pattern in bowhead and sei whale calls, both fin and humpback whales had a peak in acoustic activity during the night. These findings provide a new understanding of the acoustic presence of baleen whale species, highlighting the TAOI's ecological significance for these whales and the importance of addressing environmental factors in monitoring low-frequency vocalizations.