This paper reports on the acoustic detection of bowhead whale (Balaena mysticetus) songs from the Bering-Chukchi-Beaufort stock, including the first recordings of songs in the fall and early winter. Bowhead whale songs were detected almost continuously in the Chukchi Sea between October 30, 2007 and January 1, 2008 and twice from April 16 to May 5, 2008 during a long-term deployment of five acoustic recorders moored off Point Lay and Wainwright, AK, between October 21, 2007 and August 3, 2008. Two complex and four simple songs were detected. The complex songs consisted of highly stereotyped sequences of four units. The simple songs were primarily made of sequences of two to three moan types whose repetition patterns were constant over short periods but more variable over time. Multiple song types were recorded simultaneously and there is evidence of synchronized song variation over time. The implications of the spatiotemporal distribution of song detection with respect to the migratory and mating behavior of western Arctic bowheads are discussed.

A free‐drifting 14‐sonobuoy array was used to localize North Atlantic right whales (Eubalaena glacialis) in the Grand Manan Basin area of the Bay of Fundy. This area is a primary summer/autumn right whale habitat and overlaps an international shipping lane. The three‐hour deployment on a single day provided two‐dimensional localization of 94 right whale sounds based on arrival time differences determined from spectrogram cross‐correlation analysis. The sounds were of two distinct types: tonal and gunshot. Maximum detection distances were about 30 km for both types of sound. The mean RMS location error was 1.8 km for tonal‐type sounds and 2.5 km for gunshot‐type sounds. The average RMS error was 20% of the average distance from the receiving hydrophones, the primary source of error being uncertainty in the sonobuoy positions.

JASCO Applied Sciences provided acoustic data collection services to Shell Offshore Incorporated in support of their explorations of the Chukchi and Beaufort Seas during the summer of 2007. A total of 37 Ocean Bottom Hydrophones data recording systems were deployed resulting in a data set in excess of 5 TB. This data equates to almost 5 years of continuous sound recording. This campaign provided information on the migration routes of the marine mammals, which include bowhead, beluga, humpback, gray whales and walruses. Given the large amount of data, manual analysis of the recordings was not feasible. A method to detect and classify the marine mammal vocalizations automatically in a reasonable amount of time had to be developed. The processing is structured in several steps, 1.) the detection of energy events, 2.) the feature extraction, and 3.) the classification into a species variety. This paper focuses on combining the Gaussian Mixed Models (GMM) algorithm for classification with attributes taken from two different feature extraction algorithms: cepstral coefficients and wavelets.Combinations of these different algorithms are compared using classification operating characteristic (COC) curves for each species tested. This paper compares the performance of these algorithms and their parameters against a large training data set.

ABStrACt. Beluga calls were detected during two consecutive deployments of autonomous acoustic recorders in the northeastern Chukchi Sea. During the first deployment, calls were recorded between July and October 2007, primarily near the Barrow Canyon in July and August. During the second deployment, calls were detected in November 2007 off Point Lay and again between mid-April and June 2008 in a broad area 90 -150 km off Point Lay and Wainwright, Alaska. The summer and fall 2007 detections were consistent with movement and residency patterns identified through satellite tagging studies. In the following spring, detections were recorded by four out of five monitoring stations for 19 to 37 consecutive days (depending on the station) between 13 April and 21 June 2008. These acoustic detections provide additional information about the timing and distribution of beluga migrations in the Chukchi Sea in spring.

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Western Arctic bowhead whales (Balaena mysticetus) transit through the Chukchi Sea in spring and fall during their seasonal migration between their winter grounds in the Bering Sea and their summer feeding grounds in the Beaufort Sea, where their presence is well documented. Comparatively little is known about their use of the Chukchi Sea in summer and winter. Here results are presented from a long-term passive acoustic monitoring program using a multi-recorder array deployed from late July 2007 through July 2008 in this area. Bowhead calls were recorded intermittently between August 2007 and January 1, 2008 and again from May 27, 2008 until the end of the study. Of particular interest is the detection of songs in late fall–early winter, which had previously only been recorded during the northward spring migration. They were compared to songs recorded off West Greenland during the previous mating season and found to be different. This is the first evidence of geographic variation of bowhead songs. Overall these detections provide new information on bowheads’ spatiotemporal use of the Chukchi Sea. The successes of the study also highlight the effectiveness of autonomous underwater acoustic recorders for marine mammal surveys in remote locations.