Thesis (Ph. D.)--University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 216-229).

Thesis (M.S.)--Memorial University of Newfoundland, 1996. / Includes bibliographical references (leaves 135-147).

Thesis (Ph.D.)--McMaster University, 2005. / Advisor: Bradley N. White. Includes bibliographical references (p. 145-165). Also available online.

Thesis (M.S.) in Marine Bio-Resources--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 39-43).

Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Hawaii at Manoa, 2003. / Includes bibliographical references.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 68-80.

These (Ph.D.)--Boston University, 2008. / Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references (leaves 178-194). Also issued in print.

CIVINS / Blainville's beaked whales (Mesoplodon densirostris) use broadband, ultrasonic echolocation signals (27 to 57 kHz) to search for, localize, and approach prey that generally consist of mid-water and deep-water shes and squid. Although it is well knownthat the spectral characteristics of broadband echoes from marine organisms are a strong function of size, shape, orientation and anatomical group, little is known as to whether or not these or other toothed whales use spectral cues in discriminating between prey and non-prey. In order to study the prey-classification process, a stereo acoustic tag was mounted on a Blainville's beaked whale so that emitted clicks and corresponding echoes from prey could be recorded. A comparison of echoes from prey selected by the whale and those from randomly chosen scatterers suggests that the whale may have, indeed, discriminated between echoes using spectral features and target strengths. Specifically, the whale appears to have favored prey with one or more deep nulls in the echo spectra as well as ones with higher target strength. A three-dimensional, acoustic scattering model is also developed to simulate broadband scattering from squid, a likely prey of the beaked whale. This model applies the distorted wave Born approximation (DWBA) to a weakly-scattering, inhomogeneous body using a combined ray trace and volume integration approach. Scatterer features are represented with volume elements that are small (less than 1/12th of the wavelength) for the frequency range of interest (0 to 120 kHz). Ranges of validity with respect to material properties and numerical considerations are explored using benchmark computations with simpler geometries such as fluid-filled spherical and cylindrical fluid shells. Modeling predictions are compared with published data from live, freely swimming squid. These results, as well as previously published studies, are used in the analysis of the echo spectra of the whale's ensonified targets. / CIVINS

On Mesoscale Population Study cruises during summers 2004 and 2005 aboard the sailboat Summer Breeze, researchers from the Sperm Whale Seismic Study (SWSS) surveyed for sperm whales along the continental slope of the northern Gulf of Mexico. SWSS scientists tracked 35 groups of whales during these two summers, recording locations where they did and did not encounter whales. Whales were encountered during both summers at approximately the same frequency (19 groups in 38 survey days in 2004; 16 groups in 29 survey days in 2005), but fluke photo-identifications indicated that 85% of individuals encountered during summer 2005 had never been previously identified in the Gulf throughout 10 years of cetacean research. Composition and distribution of these groups also varied between summers. Oceanographic conditions at the edge of the continental shelf differed between 2004 and 2005, which may have modified the usual trophic cascade that begins with near-surface primary production to create local aggregations of prey at the depths where sperm whales forage. Sperm whales are apex, mesopelagic predators, but have been shown to associate with surface primary productivity over large spatial scales and time scales of months to years. The purpose of this thesis was to look for relationships between sperm whale presence and surface oceanography on smaller spatial and shorter temporal scales. Surface ocean color from NASA’s Moderate Imaging Spectroradiometer (MODIS) and surface dynamic height from NASA’s Earth orbital altimeters were evaluated to assess habitat occupied by sperm whales. Passive acoustic monitoring along transect lines for sperm whale clicks permitted determination of sperm whale presence and absence. Sperm whale encounters were in general associated with negative sea surface height and enhanced sea surface chlorophyll (SSC), especially in or near areas where local SSC anomaly was produced by cyclone induced upwelling of nutrients or from coastal water advected off-margin. During summer 2004, SSC was generally high all along the upper continental slope whereas summer 2005 saw relatively low SSC along the upper continental slope. Whales encountered in this study were most highly correlated with SSC two weeks after the initial development of locally highest-SSC anomalies.