The development of short-term high-resolution movement and acoustic archival tags has enabled a greater understanding of baleen whale dive and feeding behavior. Recent advances in battery life, data storage, and concomitant increases in sampling rate capabilities have driven interest in developing high-resolution archival tags for multi-day deployments. Using modified time-depth recorder tags (Wildlife Computers), new dart-attachments were tested on 53 humpback, fin, and blue whales and allowed attachment duration for up to 16.4 days. These medium-duration tags were used within behavioral response experiments from 2013 to 2015, including ship-noise paybacks and controlled exposure experiments (CEEs) with real mid-frequency active military sonar. In 2016, we modified acoustic multi-sensor tags (Greeneridge Sciences) with the new dart-attachments and tagged 6 blue whales, resulting in 530 hr of dive and 1195 hr of acoustic data, and 2 fin whales, resulting in 179.5 hr of dive and 77 hr of acoustic data. The tags included a pressure sensor; three-axis accelerometer, magnetometer, and gyroscope; and added Fastloc GPS sensor, which will allow for three-dimensional reconstruction and analysis of movement. Across all blue whale deployments, 1624 A, 2923 B, and 968 D calls were recorded. Fin whale deployments yielded 500 40-Hz calls. Fifteen close ship encounters were recorded on two tag deployments. Received ship noise coupled with AIS data that allows ship identification and calculation of true distances enables us to investigate potential impacts of ship presence and ship noise on behavior during close encounters. Similarly, tag data from CEE periods during the Southern California Behavioral Response Study (SOCAL-BRS) were used in conjunction with other data collected to understand whale response to military sonar signals. These novel medium-duration acoustic tags support a more detailed picture of spatial movement, dive behavior, and calling rates, and provide insight into the anthropogenic threats facing endangered baleen whales.
Citation:
Szesciorka, A., A. Sirovic, L. Lewis, J. Fahlbusch, N. Harrison, B. Southall, J. Calambokidis. 2017. Medium-duration archival tags provide unique insights into baleen whale behavior. Abstract (Proceedings) 22nd Biennial on the Biology of Marine Mammals, Halifax, Nova Scotia, October 22-27, 2017.
Download PDF