UNIVERSITY OF CALIFORNIA, SAN DIEGO Blue and fin whale acoustics and ecology off Antarctic Peninsula A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Oceanography by Ana Širović Committee in charge: Dr. John A. Hildebrand, Chair Dr. Jay Barlow Dr. Russel Lande Dr. Dariusz Stramski Dr. Maria Vernet Dr. Clinton D. Winant 2006 Copyright Ana Širović, 2006 All rights reserved The dissertation of Ana Širović is approved, and it is acceptable in quality and form for publication on microfilm: Chair University of California, San Diego 2006 iii “Nature, rightly questioned, never lies.” A Manual of Scientific Enquiry, Third Edition, 1859 iv Table of contents Signature page..................................................................................................................iii Dedication........................................................................................................................iv Table of contents..............................................................................................................v List of figures...................................................................................................................ix List of tables.....................................................................................................................xiii Acknowledgements..........................................................................................................xiv Vita……………………………………………………………………………………..xvii Abstract............................................................................................................................xix I. Introduction ..................................................................................................................1 A. Physical oceanography of the Antarctic Peninsula...................................2 Bathymetry...............................................................................................2 Wind.........................................................................................................3 Sea ice ......................................................................................................4 Circulation ...............................................................................................5 Hydrography ............................................................................................6 Sound propagation characteristics ...........................................................7 B. Biological oceanography of the Antarctic Peninsula................................9 Phytoplankton ..........................................................................................9 Krill..........................................................................................................10 C. Whaling history of the Antarctic Peninsula ..............................................11 D. Dissertation goals......................................................................................15 II. Seasonality of blue and fin whale calls and the influence of sea ice in the Western Antarctic Peninsula..........................................................................................................17 A. Abstract .....................................................................................................17 B. Introduction...............................................................................................17 v C. Methods.....................................................................................................20 D. Results.......................................................................................................26 E. Discussion .................................................................................................38 F. Conclusions ...............................................................................................42 G. Acknowledgements...................................................................................43 III. How far can blue and fin whales be heard in the Southern Ocean? ..........................44 A. Abstract .....................................................................................................44 B. Introduction...............................................................................................44 C. Methods.....................................................................................................46 Multipath arrivals.....................................................................................47 Time difference of arrival and hyperbolic localization ...........................49 Source level calculations .........................................................................51 Sound propagation modeling ...................................................................52 D. Results.......................................................................................................53 Blue whales..............................................................................................54 Fin whales ................................................................................................57 E. Discussion .................................................................................................58 F. Acknowledgements....................................................................................61 IV. Fall habitat of calling blue and fin whales off the Western Antarctic Peninsula ......63 A. Abstract .....................................................................................................63 B. Introduction...............................................................................................64 C. Methods.....................................................................................................67 Environmental data collection .................................................................69 Passive acoustic data collection and analysis ..........................................71 Spatial analysis ........................................................................................73 D. Results.......................................................................................................75 vi Qualitative comparison............................................................................75 Modeling results ......................................................................................82 E. Discussion .................................................................................................84 Blue whale distribution............................................................................84 Fin whale distribution ..............................................................................86 Data limitations........................................................................................87 F. Acknowledgements....................................................................................89 V. Baleen whales in the Scotia Sea in January and February 2003.................................90 A. Abstract .....................................................................................................90 B. Introduction...............................................................................................91 Call characteristics...................................................................................93 C. Methods.....................................................................................................95 Acoustic survey........................................................................................97 Comparison with visual survey................................................................99 D. Results.......................................................................................................100 Southern right whales ..............................................................................100 Blue whales..............................................................................................101 Fin whales ................................................................................................102 Humpback whales....................................................................................104 Minke whales...........................................................................................106 Other calls ................................................................................................106 E. Discussion .................................................................................................107 Sources of calls ........................................................................................107 Whale distributions and environmental parameters.................................111 F. Acknowledgements....................................................................................114 VI. Conclusions ...............................................................................................................115 vii A. Dissertation synethesis..............................................................................115 B. Observation and analyses needs................................................................117 References........................................................................................................................121 viii List of figures I. Introduction Figure 1.1. Map of the Antarctic Peninsula region with major currents and fronts…...3 Figure 1.2. Sound propagation