Baleen whale acoustic activity in the North Pacific: historical analysis and current occurrence

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Authors
Stafford, Kathleen M.
Subjects
Advisors
Date of Issue
2007
Date
2007
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
Unclassified historic acoustic data were used to examine long time scale changes in the seasonal and geographic occurrence of large whales in the Pacific and to correlate these changes with oceanographic variables such as sea surface temperature, chlorophyll a, etc. Distribution of northeastern Pacific blue whales (as indicated by the numbers of their calls), while insignificantly related to SST, did show a clear seasonal pattern both to chl a concentration (negative) and to the mixed layer depth (positive). It was speculated that the negative correlation with chl a might be due to a lag from primary to secondary productivity: as phytoplankton are eaten by zooplankton (which in turn become available to whales), the overall amount of chl a decreases. It is recommended that in collaboration with other agencies hydrophones be deployed in the northeastern Gulf of Alaska to provide current information on the occurrence of vocally active whale species, including low frequency baleen whales and higher frequency odontocetes. A likely time might be during the Northern Edge 2008 exercise in Prince William Sound. Meanwhile, a new efficient, low-power, low-cost recorder that can be easily deployed, in an array with other instruments or independently, from a mid-size vessel is being developed.
Type
Technical Report
Description
Series/Report No
Department
Oceanography
Organization
Identifiers
NPS Report Number
NPS-OC-08-003
Sponsors
Funder
N00024-02-D-6602.
Format
ii, 25 p.: ill. (some col.) 28 cm.
Citation
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.