Acoustic occurrence and affiliation of fin whales detected in the Northeastern Chukchi Sea, July to October 2007–10 (PDF)

Delarue, J.J.-Y., B. Martin, D.E. Hannay, and C.L. Berchok

Arctic 66: 159-172 (2013)

DOI: 10.14430/arctic4287

Fin whales are common throughout the North Pacific region, particularly in the Gulf of Alaska and the Bering Sea, even though these areas were heavily depleted by decades of whaling. Whalers also took fin whales in the southwestern Chukchi Sea, but only five sightings have been reported for the entire Chukchi Sea in the past 30 years. Large-scale arrays consisting of 26 – 44 bottom-mounted acoustic recorders were deployed in the northeastern Chukchi Sea from July to October in 2007 to 2010. Fin whales were detected off Cape Lisburne and Point Lay in 2007, 2009, and 2010. Large interannual variations in the number of acoustic detections may be related to environmental conditions. Calls detected during summer months consisted primarily of irregular sequences. Stereotyped sequences, called songs, were also detected at the end of the recording period in 2007 and 2010. Their structure matched that of one of the songs recorded in the Bering Sea, suggesting that only one of the stocks occurring in the Bering Sea extends its range into the northeastern Chukchi Sea. These detections currently represent the northernmost fin whale records in the North Pacific region.

Marine mammal acoustic detections in the northeastern Chukchi Sea, September 2007–July 2011

Hannay, D.E., J. Delarue, X. Mouy, B.S. Martin, D. Leary, J.N. Oswald, and J. Vallarta

Continental Shelf Research 67: 127-146 (2013)

DOI: 10.1016/j.csr.2013.07.009

Several cetacean and pinniped species use the northeastern Chukchi Sea as seasonal or year-round habitat. This area has experienced pronounced reduction in the extent of summer sea ice over the last decade, as well as increased anthropogenic activity, particularly in the form of oil and gas exploration. The effects of these changes on marine mammal species are presently unknown. Autonomous passive acoustic recorders were deployed over a wide area of the northeastern Chukchi Sea off the coast of Alaska from Cape Lisburne to Barrow, at distances from 8 km to 200 km from shore: up to 44 each summer and up to 8 each winter. Acoustic data were acquired at 16 kHz continuously during summer and on a duty cycle of 40 or 48 min within each 4-h period during winter. Recordings were analyzed manually and using automated detection and classification systems to identify calls.

Underwater noise from offshore oil production vessels (PDF)

Erbe, C., R.D. McCauley, C.R. McPherson, and A. Gavrilov

Journal of the Acoustical Society of America 133: EL465-EL470 (2013)

DOI: 10.1121/1.4802183

Underwater acoustic recordings of six Floating Production Storage and Offloading (FPSO) vessels moored off Western Australia are presented. Monopole source spectra were computed for use in environmental impact assessments of underwater noise. Given that operations on the FPSOs varied over the period of recording, and were sometimes unknown, the authors present a statistical approach to noise level estimation. No significant or consistent aspect dependence was found for the six FPSOs. Noise levels did not scale with FPSO size or power. The 5th, 50th (median), and 95th percentile source levels (broadband, 20 to 2500 Hz) were 188, 181, and 173 dB re 1 μPa @ 1 m, respectively.