ARCTIC Observations on the Behavioral Responses of Bowhead Whales (Balaena mysticetus) to Active Geophysical Vessels in the Alaskan Beaufort Sea

• Main Authors: Donald K. Ljungblad, Bernd Wursig, Steven L. Swartz, James M. Keene
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1988
• Subjects: Arctic; Mer de Beaufort; Balaena mysticetus; Beaufort Sea; bowhead whale; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.514.8880; http://pubs.aina.ucalgary.ca/arctic/Arctic41-3-183.pdf

ABSTRACT. The responses of bowhead whales to controlled approaches by geophysical vessels producing airgun blasts were observed during the course of four field experiments conducted in the Alaskan Beaufort Sea in September 1984. Behavioral responses included shorter surfacing and dive times, fewer blows per surfacing, longer blow intervals and subtle to overt changes in surface behaviors. Subtle behavioral responses occurred at 3.5 and 8.2 km with received airgun noise levels of 142 and 157 dB respectively (all levels in dB re 1pPa). Partial avoidance (Le., some whales leaving the observation area while others remained) occurred at ranges of 3.5 and 7.6 k m, with sound levels of 142 and 158 dB respectively. Total avoidance (i.e., all whales1eavingtheobservationarea)occurredat 1.3,7.2,3.5and2.9km,withcorrespondingsoundlevelsof152, 165,178and165dB.Thesimilarities among experiments reported here support the conclusion that short-term behavioral changes occur when bowhead whales are exposed to airgun blasts from approaching geophysical vessels at ranges < 10k m. These disturbance effects wane within one hour after a disturbance; long-term effects on social, behavioral or physiologic parameters are not known at this time. Key words: bowhead whale, Balaena mysticerus, geophysical vessel, bioacoustics, airguns RESUME. Au cours de quatre exp6riences sur le terrain, mentes dans la mer de Beaufort de 1’Alaska en septembre 1984, on a ttudit le comportement des baleines franches en rkponse a l’approche contr6lte de navires de prospection gtophysique qui tmettaient des ondes de choc B I’aide de canons B air. Parmi les comportements provoquts, on a remarque une diminution du temps B la surface et du temps en plongte, une diminution du nombre de souffles par remontte B la surface, une augmentation de l’intervalle entre les souffles ainsi que des changements dans le comportement B la surface, allant de p u