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Understanding what psycho-physiological and behavioural factors influence aversiveness of sound in marine mammals is important for conservation and practical applications. The aim of this study was to determine predictors for impact of anthropogenic noise and to develop a target-specific predator deterrence system for use on fish farms. Three classes of stimuli were tested: 1.) grey seal underwater communication calls expected to be used in territorial defence, 2.) high duty-cycle moderately loud artificial sounds (some of which were based on models of unpleasantness for humans), 3.) brief, intense pulses designed to elicit the acoustic startle reflex. Communication calls had no deterrence effect but instead caused attraction responses. Tests with high duty-cycle artificial sounds showed that food-motivated animals habituate quickly, although sound exposure caused subtle changes in diving patterns over a longer time. Field trials using the same stimuli were used to determine avoidance thresholds but also indicated that sound features like ‘roughness’ play a role. The startle eliciting stimuli, however, had the most dramatic effects. To this stimulus most seals exhibited rapid flight responses, hauled out, sensitised and showed signs of fear conditioning. Startle thresholds were found to be 80-85 dB above the assumed hearing threshold. The data showed that startle thresholds are a crucial predictor for the occurrence of strong avoidance behaviour and suggests that the startle response evolved to increase an animal’s propensity for flight. Finally, a prototype predator deterrence system based on the startle sounds was developed to repel seals whilst not affecting toothed whales. In fish farm trials, seals were deterred at close ranges but local abundance of cetaceans did not change showing that it is possible to cause differential responses between species based on differences in their audiograms. The results are used to develop noise exposure criteria and to elucidate acoustic parameters that can be used to predict responses to anthropogenic noise.

Recently, there has been an increase in marine mammal mortalities, most commonly Atlantic bottlenose dolphins, Tursiops truncatus, which is an alarming indication of the health status of the marine ecosystem. Studies have demonstrated that some free-ranging dolphins exhibit a suppressed immune system possibly because of exposure to contaminants or infectious microorganisms. However, this research has been limited due to a lack of commercially available marine-specific antibodies. Therefore, the first chapter of this thesis aims to identify cross-reactive terrestrial-specific antibodies that could be used to phenotype and compare the immune cell populations of dolphins under human care and free-ranging dolphins. The second chapter aims to utilize terrestrial-specific growth factors and dendritic cell (DC) surface markers to generate, characterize, and compare ex vivo DCs from peripheral blood mononuclear cells (PBMCs) of dolphins under human care and free-ranging dolphins. In summary, I have identified differences within the PBMCs and ex vivo generated DCs of dolphins under human care and free-ranging dolphins that could potentially shed light on the impact of environmental contaminants and infectious microorganisms on immune cells which could lead to increased morbidity and mortality. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

In this thesis, research by Crum and Mao [J. Acoust. Soc. Am. 99, 2898--2907 (1996)] and Houser, Howard, and Ridgway [J. Theor. Biol. 213, 183--195 (2001)] is extended by numerically investigating bubble growth (initial radius of 10 microns) during rectified diffusion for gas supersaturations up to 300% by using the Fyrillas-Szeri equation [J. Fluid Mech. 277, 381--407 (1994)]. Bubble growth is simulated for a range of frequencies (100 Hz to 10 kHz), sound pressure levels (205 dB to 215 dB re 1 micropascal), and gas supersaturations (150% to 300%). Simulations are presented for continuous and monofrequency excitation, repeated tone bursts, and pulsed frequency-modulated waveforms. The potential for bubble growth to occur in marine mammals is also considered. For the parameters considered, static diffusion becomes the dominant growth mechanism as supersaturation is increased, bubble growth is frequency independent away from bubble resonance, and bubble growth due to duty-cycle excitation can be modeled as an effective continuous source with a reduced sound pressure level. A more accurate model of in vivo marine mammal tissue is required to determine if rectified diffusion can trigger bubble growth at the levels predicted in this thesis. / text

Approved for public release, distribution unlimited / This study sought to experimentally quantify the sonar performance of omni-directional receivers as a means to passively detect vocalizing Odontocetes. To accomplish this objective, controlled experiments using a calibrated mid-frequency sound source were conducted on the San Clemente Island Underwater Range (SCIUR) in July 2002. Six Odontocete signals were selected for transmission: 2 orca and 2 pilot whale whistles, and sperm whale and Risso's dolphin clicks. Several hundred iterations of each signal were broadcast at stations 300 m to 12,000 m from the range's moored, three-element array. Statistical analyses were performed on the output of an energy and matched filter detector to quantify detection probability (P(D)) and range limits as a function of false alarm rate (P(FA)), signal type, and signal to noise ratio (SNR). The matched filter was generally the superior performer, detecting the orca2 and pilot1 whistles beyond 5000 m with a 90% P(D), 1% P(FA), and source level (SL) of 140 dB re 1 æPa. For the same conditions, the orca1 and sperm whale calls were detected at 1500 m, but the pilot2 and Risso's dolphin signals were not detected at the peak realized SNR of (-2) dB. The energy detector had no detections with a 90% P(D) and 1% P(FA) at this (-2) dB SNR, but all signals except one orca whistle were detectable beyond 1000 m with a 50% P(D) and 1% P(FA). The sperm whale was the exceptional energy detector performer, with detection ranges exceeding 7 km (140 dB re 1 æPa SL) at the 50% P(D) and 1% P(FA) / Lieutenant Commander, United States Navy

<p>Sea turtles, marine mammals and sea birds are vulnerable to higher mortality rates as a direct function of incidental capture (bycatch) in marine fisheries. Their migratory behavior exposes them to multiple fishing gear types and fishing practices and efforts to understand the rates of interaction between these taxa and fishing necessarily entails analysis of data over large spatial areas (ocean-basin) and multiple types of fishing activities. The acquisition the requisite data, however, requires considerable resources and many regions in the world are data-poor with respect to bycatch, including the Wider Caribbean Region (WCR) in the west central Atlantic Ocean basin. This dissertation presents the results of multiple strategies used to assess sea turtle, marine mammal and seabird bycatch in the WCR, with a particular focus on sea turtle bycatch. The research incorporated a synthetic review of the literature, expert consultation, statistical techniques, and geospatial analyses to assess the bycatch seascape for the region. I conclude that sea turtle bycatch in the WRC is significantly linked to turtle rookeries, especially those on the continental land mass and in the southern section of the Caribbean basin, in large part because of the near shore artisanal nature of the fisheries and the importance of these habitats for foraging and reproduction. The limited information on marine mammal bycatch does not permit robust inferences, but it clearly identifies threats to at least one vulnerable marine mammal species, the tucuxi (Sotalia fluviatilis). Information on seabird bycatch was even more limited; the most vulnerable seabird populations occur in the higher latitudes (temperate zones) while the seabird populations in the WCR face significant threats from habitat loss and over-exploitation. This dissertation proposes specific recommendations for improving and advancing the information base for a regional, ecosystem-level management and mitigation of bycatch.</p> / Dissertation

Tuna-dolphin-bird feeding assemblages are unique to the Eastern Tropical Pacific Ocean (ETP). These multiple species groups are believed to forage together in response to the physical properties of the near surface ocean as these constrain the distribution of prey. In the Galapagos Marine Reserve (GMR), intra-annual and interannual changes affect the properties of the water column, inducing mesoscale and fine scale temporal variability. Four three-week oceanographic surveys took place, in September 2008, April 2009, October 2009, and September 2010, between the coast of Ecuador and the Galapagos Islands and one small boat survey took place in June 2010 within the GMR. Marine mammal surveys were conducted during daylight hours and Conductivity, Temperature, Depth (CTD) sensor casts were taken throughout the survey. Data were analyzed to determine the types of water masses present and the strength and depth of the thermocline layer. These data were compared with the sightings of marine mammals, bird feeding groups, and tuna-dolphin-bird assemblages. Additionally, these data were used to predict where tuna would be likely to associate with dolphin groups. Results show Equatorial Surface Water was the dominant water mass throughout the archipelago, regardless of season or ENSO index. High salinity, cold water west of Isla Isabela indicated topographic upwelling of the Equatorial Undercurrent. Tropical Surface Waters from the Panama Current were detected north of the Equatorial Front to the east of the islands. Obvious changes in the water column properties were observed between El Niño and La Niña events in the GMR. Most mixed groups were sighted west and south of Isla Isabela during the four oceanographic surveys, as well as north and west of Isla San Cristobal in June 2010. Most sightings were in cool, high salinity waters, and high chlorophyll concentrations. There were a greater number of sightings during the April 2009 survey (ENSO-neutral conditions) than during any of the three fall surveys. Additionally, tuna-dolphin-bird groups were more likely to be seen near Isla Isabela, with the majority of them sighted during the April 2009 survey and a few sighted in each of the September 2008 and October 2009 surveys. No tuna-dolphin-bird groups were sighted during the September 2010 surveys. Results show that the presence and location of these multi-species groups may be controlled by the inter-annual cycles, the intra-annual cycles, or a combination of both types of changes seen within the Galapagos.

Thesis (M.S.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (January 14, 2010) Includes bibliographical references (p. 82-94)

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [110]-122).

Thesis (M. Sc.), Memorial University of Newfoundland, 1999. / Bibliography: p. 169-179.