[MARMAM] New article- Southern Ocean Whale & Seal acoustic survey [Sec=Unclassified]

Jason Gedamke Jason.Gedamke at aad.gov.au
Wed Aug 25 17:56:13 PDT 2010


Colleagues,

This recently published article is available online.  Of particular interest were acoustic detections of pygmy blue whale sounds in the Southern Ocean; the first published descriptions of new Ross seal vocalizations; the far northerly distribution of leopard seal detections; and the regional 'dialect' associated with fin whale song.  The abstract follows with more details.

Gedamke, J. and Robinson, S.M. 2010. Acoustic survey for marine mammal occurrence and distribution off East Antarctica (30-80°E) in January-February 2006.  Deep Sea Research Part II: Topical Studies in Oceanography  Volume 57, Issues 9-10, May 2010, Pages 968-981.

If interested, you can download it at http://dx.doi.org/10.1016/j.dsr2.2008.10.042
or request it by contacting me directly.

Cheers,
Jason


Abstract
A large scale, systematic, acoustic survey for whales and seals in eastern Antarctic waters was conducted in January-February 2006. During the BROKE-West survey of Southern Ocean waters between 30 and 80° E longitude, an acoustic survey was conducted to complement a traditional visual survey for marine mammal occurrence and distribution. As part of the survey, 145 DIFAR sonobuoys were deployed every 30' of latitude on north-south transects, and prior to CTD stations on the initial east-west transect. Underwater sound was analyzed for 70 minute samples from each sonobuoy. Blue whales were the most commonly recorded species, identified at 55 of the sonobuoy deployment sites. Other species recorded include: sperm (46 sites), fin (14), humpback (2), and sei (3) whales, and leopard (11) and Ross (17) seals. Large numbers of blue and sperm whales, and all Ross seals were detected on the westernmost two transects, which were the only transects of the survey with relatively extensive sea ice remaining off the continental shelf. Large numbers of blue whales were also detected in the more eastern waters of the survey off the Prydz Bay region, while two detections of pygmy blue whales represent the farthest south these whales have been recorded. Of the relatively few fin whale detections, most occurred in more northerly waters. Fin whale vocalizations from this region were distinctly different than those recorded elsewhere around Antarctica suggesting acoustic recordings may be useful to delineate regional or stock boundaries of this species. Previously undescribed sounds were attributed to Ross seals. Acoustic detections of these and leopard seal sounds indicate these animals venture further from their traditionally described distributions, with vocalizing leopard seals occurring much further north than might be expected. Overall, the results of the sonobuoy survey provide a measure of each species' relative spatial distribution over the survey area based on acoustic detections, and when combined with the results of the visual survey, will provide a comprehensive view of marine mammal distribution throughout the region during the BROKE-West survey.

____________________________
Jason Gedamke, PhD
Australian Marine Mammal Centre
Australian Antarctic Division
203 Channel Highway
Kingston, TAS 7050

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