Bowhead whales and airgun pulses: Detecting a threshold of behavioral reaction

Citation

Blackwell, S. B., T. L. McDonald, C. S. Nations, A. M. Thode, K. H. Kim, C. R. Greene, and M. A. Macrander (2012). “Bowhead whales and airgun pulses: Detecting a threshold of behavioral reaction”. In: The Journal of the Acoustical Society of America 132.3, p. 1949. DOI: 10.1121/1.4755172.

Number of Citations: 1

Abstract

Previous work has shown that bowhead whales cease calling when near (<40 km) seismic exploration activities involving airguns. The aim of this study is to estimate the received level threshold for the onset of this behavior (cessation of calling). The analysis relied on data collected during late summer of 2007-2010 by up to 40 Directional Autonomous Seafloor Acoustic Recorders (DASARs) in the Beaufort Sea. About 98,000 localized calls and hundreds of thousands of airgun pulses were included in the analysis. For each 10-min period of data collected at each recorder, each year, the cumulative sound exposure level (CSEL) from airgun pulses was calculated and paired with the number of calls concurrently localized within $$3.5 km of each DASAR. Poisson regression was then used to estimate the threshold of airgun sound exposure received at the whales when call cessation begins. The CSEL threshold was found to be near 124 dB re 1 \(\mu\)Pa2 s (95% confidence intervals = 119-129 dB). For an airgun array firing every 10 sec, this corresponds to a received single pulse SEL at the whale of $$106 dB re 1 \(\mu\)Pa2 s. [Work supported by Shell Exploration and Production Company.]