Acoustic localization of bowhead whales near a Beaufort Sea oil development, 2001–2003: Evidence of deflection at high-noise times?

Citation

Richardson, W. J., T. L. McDonald, C. R. Greene Jr, S. B. Blackwell, and B. Streever (2004). “Acoustic localization of bowhead whales near a Beaufort Sea oil development, 2001-2003: Evidence of deflection at high-noise times?” In: The Journal of the Acoustical Society of America 116.4, p. 2589. DOI: 10.1121/1.4785327.

Number of Citations: 1

Abstract

Most bowhead whales migrating west along Alaska’s north coast during autumn pass 10–75 km seaward of BPs Northstar oil production island. Our objective was to determine the extent to which underwater sound from Northstar deflected the closest whales farther offshore. Whale calls were localized, via 11 DIFAR-based seafloor recorders, on 23–36 days per year while underwater sound was measured continuously 450 m from Northstar. Totals of 1121, 2057 and 14304 calls were localized within a 20$$26 km analysis area seaward of Northstar. Quantile regression was used to relate the 5th quantile distance-from-shore to underwater sound. A permutation method allowed for lack of independence of closely spaced calls. In 2001, the closest calling bowheads tended to be slightly farther offshore at times with high industrial sound, which were mainly due to vessels near Northstar. The displacement effect was maximal if sound was averaged over 50–80 minutes preceding calls. In 2002, high sound levels were rare and results were inconclusive. In 2003, offshore displacement was not significant despite high sample size and a migration corridor unusually close to shore. The upper 90% confidence bound on the percentage of bowheads displaced 2+ km did not exceed 1.6% in any year. [Work supported by BP.]