Date of Award

2006

Level of Access Assigned by Author

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Interdisciplinary Program

Advisor

Michael Peterson

Second Committee Member

John Riley

Third Committee Member

Mark Johnson

Abstract

A cross-species comparison was conducted using representative whales (Balaenoptera musculus, Megaptera novaeangliae, Eschrichtius robustus, and Eubalaena glacialis) from each of the major mysticete families with distinctly different body morphologies. Morphological and osteological data sets were used in conjunction with DTAG recorded subsurface behaviors to examine the effect of a whale’s morphology on its swim performance. The morphological configurations of the whales lent themselves to the following classifications based on hydrodynamic principles: fast cruiser, slow cruiser, fast maneuverer, and slow maneuverer. The blue whale is designed for steady, high speed, efficient cruising in a pelagic environment with low maneuverability requirements. A highly streamlined body combined with small, high aspect ratio flippers and flukes and long lever arms on the vertebrae provide efficient high speed travel between widely dispersed prey patches. In contrast, the right whale’s body form is optimized for efficient slow speed swimming. Tag data suggests that right whales stroke 95% of the time while feeding at depth. A large, high aspect ratio fluke combined with short, upright neural processes in the spine provide a high endurance, efficient locomotive force to power the right whale’s high drag, continuous filtration skim feeding activities. With their unique bubble net and flick feeding techniques, humpbacks have a high maneuverability requirement. Large, high aspect ratio flippers generate large lift forces for tight turns while the large area, low aspect ratio tail provides large acceleration reaction forces suitable for quick maneuvers. Large spacings between neural processes of the vertebrae allow a high degree of flexure in the spinal column and enhance turning performance. Gray whales also have high maneuverability requirement, but at lower speeds. Rolling is highly associated with feeding activities. A flexible vertebral design and large, low aspect ratio flippers and flukes allow for precise positioning and maneuvering in complex coastal water habitats.

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