Distribution of bowhead whale calls near an oil production island with fluctuating underwater sound

Citation

Richardson, W. J., T. L. McDonald, C. R. Greene, S. B. Blackwell, and B. Streever (2012). “Distribution of bowhead whale calls near an oil production island with fluctuating underwater sound”. In: The Effects of Noise on Aquatic Life. Ed. by A. N. Popper and A. Hawkings. Springer, pp. 303-306. DOI: 10.1007/978-1-4419-7311-5_67.

Number of Citations: 2

Abstract

Bowhead whales (Balaena mysticetus) migrate west along the north coast of Alaska during late summer and autumn, passing near BP’s Northstar oil production facility—an artificial gravel island in the Beaufort Sea a few kilometers inshore of the migration corridor. Underwater sound from Northstar and its support vessels fluctuates as industrial operations vary, raising concern that migrating bowheads might be deflected offshore and become less accessible to Iñupiat subsistence hunters based on Cross Island. Because an a priori power analysis showed that aerial surveys could not detect a deflection of the small size expected, calling whales were instead localized over four migration seasons (2001–2004) using an array of directional autonomous seafloor acoustic recorders (DASARs). Weighted quantile regression related the offshore distance of calls to measures of industrial sound, after allowing for natural environmental covariates. The proximal (southern) edge of the call distribution was significantly associated with industrial sound output in each year; for example, in 2001 the 5th quantile of offshore distance was an estimated 1.58 km farther offshore when Northstar sound increased. The results indicate a small but detectable offshore displacement of calling bowheads at times of elevated industrial sound.