Beaked Whale Anatomy, Field Studies and Habitat Modeling

• Main Author: Hildebrand, John A.
• Other Authors: SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
• Format: Text
• Language: English
• Published: 2007
• Subjects: Biology; Anatomy and Physiology; Computer Programming and Software; Acoustics; *SOUND TRANSMISSION; *BEHAVIOR; *HABITATS; *NOISE(SOUND); *HEAD(ANATOMY); *ANATOMICAL MODELS; *WHALES; COMPUTERIZED SIMULATION; TISSUES(BIOLOGY); ACOUSTIC VELOCITY; COMPUTERIZED TOMOGRAPHY; ORGANS(ANATOMY); CALIFORNIA GULF; HEARING; SOUND PRESSURE; UNDERWATER ACOUSTICS; RECEPTION; SOUND WAVES; FINITE ELEMENT ANALYSIS; FIELD TESTS; *BEAKED WHALES; *BALEEN WHALES; WHALE SIGHTINGS; WHALE DISTRIBUTION; VOCALIZATIONS; FIELD STUDIES; HABITAT MODELING; CETACEANS; ODONTOCETE; MARINE HABITATS; BEAKED WHALE ANATOMY; SOUND RECEPTION MODELING; SOUND GENERATION MODELING; TURSIOPS TRUNCATUS; BIOLOGICAL TISSUE MODELING; ZIPHIUS CAVIROSTRIS; GULAR PATHWAY; VIBRO-ACOUSTIC TOOLBOX; Baja; Gomez; Gustavo; baleen whales; toothed whales
• Online Access: http://www.dtic.mil/docs/citations/ADA475190; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA475190

This report describes the results of two tasks related to the study of beaked whales. The first study was a field study of beaked whales in the Gulf of California from December 2004 to December 2006. The goal of the study was to determine the range of sound produced by beaked whales and to investigate beaked whale behavior and habitat. A minimum of 17 cetacean species (12 toothed and 5 baleen whales) were observed in 147 sightings. The proportion of sighted toothed whales and baleen whales was 67% and 32%, respectively. The second task was the modeling of beaked whale anatomy, the conversion of anatomy to physical properties, and the use of these in a finite element model of the effects of intense sound. To validate their methodological procedures, the authors compared CT data from live, frozen, and thawed specimens of Tursiops truncatus. The results showed that CT scans produce similar results in tissues and organs for the following quantities: geometry, absolute density, and sound velocity across live and thawed specimens. Simulated sound sources placed inside and outside of a modeled adult male beaked whale (Ziphius cavirostris) revealed pathways for acoustic propagation into and out of the head. This result supports the notion that dual sonar sources interfere constructively to form a sonar beam in front of the animal. The simulations also indicated a new "gular pathway" for sound reception. Propagated sound pressure waves enter the head from below and between the lower jaws, continuing toward the bony ear complexes through the internal mandibular fat bodies. The report titles produced through these studies are as follows: "Vocalizations and Marine Habitat of Baleen and Beaked Whales," by Gustavo Cardenas, Jorge Urban, and Alejandro Gomez-Gallardo; and "Simulated Sound Transmission and Reception in Cuvier's Beaked Whale (Ziphius Cavirostris) Using the Vibro-Acoustic Toolbox," by Ted W. Cranford, Petr Krysl, and John A. Hildebrand. Prepared in cooperation with the Universidad Autonoma de Baja California Sur, La Paz, Mexico; Quantitative Morphology Consulting, Inc., San Diego, CA; and San Diego State University, San Diego, CA. The original document contains color images.