Echolocation-Based Foraging by Harbor Porpoises and Sperm Whales, Including Effects on Noise and Acoustic Propagation

This thesis provides quantitative descriptions of toothed whale echolocation and foraging behavior, including assessment of the effects of noise on foraging behavior and the potential influence of ocean acoustic propagation conditions on biosonar detection ranges and whale noise exposure. Chapter 2...

Full description

Bibliographic Details
Main Author: DeRuiter, Stacy L.
Other Authors: MASSACHUSETTS INST OF TECH CAMBRIDGE
Format: Text
Language:English
Published: 2008
Subjects:
Biology
Biological Oceanography
Acoustics
*MARINE BIOLOGY
*AQUATIC ANIMALS
*NOISE
LEVEL(QUANTITY)
BEHAVIOR
STATISTICAL ANALYSIS
OCEANS
TARGET DETECTION
RANGE(DISTANCE)
MARKOV PROCESSES
MULTIPATH TRANSMISSION
ECHO RANGING
WHALES
SOUND TRANSMISSION
BIOSONAR
EXPOSURE(GENERAL)
THESES
ECHOLOCATION
HARBOR PORPOISES
SPERM WHALES
ACOUSTIC PROPAGATION
Sperm whale
toothed whale
Online Access:http://www.dtic.mil/docs/citations/ADA489203
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA489203
Description
Summary:This thesis provides quantitative descriptions of toothed whale echolocation and foraging behavior, including assessment of the effects of noise on foraging behavior and the potential influence of ocean acoustic propagation conditions on biosonar detection ranges and whale noise exposure. Chapter 2 details the application of a modified version of the Dtag to study harbor porpoise echolocation. Study results indicate how porpoises vary the rate and level of their echolocation clicks during prey capture events and show that, unlike bats, porpoises continue their echolocation buzz after prey capture. Chapters 3-4 emphasize the importance of applying realistic models of ocean acoustic propagation in marine mammal studies. These chapters illustrate that geometric spreading approximations sometimes provide inaccurate predictions of communication/target detection ranges or noise exposure levels, especially if refraction in the water column or multi-path acoustic propagation are significant. Finally, in Chapter 5, 1 describe two methods for statistical analysis of whale behavior data, a rotation test and a semi-Markov chain model. I use the test for changes in sperm whale foraging behavior in response to airgun noise exposure. Test results indicate that, despite the low- level exposures in the study, some whales altered their foraging behavior in response to airgun exposure. The original document contains color images. All DTIC reproductions will be in black and white. Prepared in cooperation with Woods Hole Oceanographic Inst., Woods Hole, MA.

Similar Items