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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Longitudinal Diet Studies of Arctic Whales

Matthews, Cory 11 September 2013 (has links)
An animal’s foraging ecology can vary over a range of temporal scales, mirroring seasonal and longer term changes in prey availability, as well as ontogenetic shifts in diet and distribution. Obtaining individual-based, longitudinal diet information through direct observation, however, is logistically challenging for marine mammals that pursue and consume prey underwater, and are often widely distributed. Isotopic profiling along continuously growing tissues like teeth and baleen, which archive dietary inputs at the time of growth in their stable isotope composition, allows for chronological dietary reconstructions over multi-year timespans. This thesis reports longitudinal diet studies of three Arctic whale species, killer whales (Orcinus orca), bowhead whales (Balaena mysticetus) and beluga whales (Delphinapterus leucas), derived from serial isotopic measurements along teeth and baleen. Study objectives varied by species, but general goals were to characterize seasonal, ontogenetic, and/or individual diet variation. Results revealed similar trophic-level diet, but regional spatial separation, among eastern Canadian Arctic/Northwest Atlantic killer whales. However, isotope and tooth wear differences between two individuals and the rest of the sampled whales suggested potential specialisation on sharks, while the other whales likely had diets comprising marine mammals. Cyclic isotopic variation along Eastern Canada-West Greenland bowhead whale baleen was consistent with year-round foraging, although at a reduced rate during winter. Resting zooplankton could be an important food resource outside of periods of peak productivity, and accessibility likely drives winter habitat selection. Isotopic cycling did not differ between female and male bowheads, or among age classes, indicating similar seasonal foraging patterns despite reported spatial segregation throughout their summer range. Individual beluga whales from three eastern Canadian Arctic populations varied in timing of ontogenetic diet shifts (i.e. weaning age), as well as overall trophic position, which could reflect size-specific energetic requirements and foraging capabilities. Population-specific beluga whale diet trends over a period of several decades likely reflected climate-related expansions of southern forage fish. Collectively, findings of seasonal, ontogenetic, and/or individual diet variation contribute a greater understanding of intrapopulation variation in foraging ecology of these species, and of large-scale structuring of Arctic marine ecosystems.
92

Variations in gray whale feeding behaviour in the presence of whale-watching vessels in Clayoquot Sound, 1993-1995

Bass, Joanna January 2000 (has links) (PDF)
No description available.
93

Population dynamics and distribution of northern Norwegian killer whales in relation to wintering herring

Kuningas, Sanna January 2014 (has links)
The northern Norwegian killer whale (Orcinus orca) is an important predator but little is known about its population dynamics, particular in response to changes in its main prey, the highly dynamic Norwegian spring spawning (NSS) herring (Clupea harengus). The main aims of this thesis were to estimate killer whale population parameters, to explore the future viability of the population, and to explore the response of this predator to changes in distribution and abundance of its main prey over the last 25 years. Population size was estimated as ~ 700 individuals, taking heterogeneity of capture probabilities into account and correcting for unmarked animals. Apparent survival rates of 0.974 (SE = 0.006) for adult males and 0.984 (SE = 0.006) for adult females were estimated accounting for temporary emigration, transience and trap-dependency. Temporary emigration was greater for males than females. Calving intervals ranged from 3 to 14 years (mean = 5.06); equivalent to 0.197 calves per mature female per year. Future viability of the killer whale population was evaluated under various plausible scenarios. The baseline scenario using the best available information predicted a viable population and indicated that the population may be increasing size. Analysis of data on naval sonar activity, killer whale sightings and herring abundance showed that naval sonar activity appeared to have a negative effect on killer whale presence during a period of low prey availability. A time lag of four years was found between the first sign of NSS herring changing its distribution and reduced killer whale presence inside the fjord system. Analysis of energy budgets showed that killer whales spent more time travelling/foraging in 2005/06 than the 1990s. The fjord system was inferred to be a preferred habitat for killer whales when there was a higher density of NSS herring in this area compared to offshore area.
94

Bowhead whale localization and environmental characterization in the Chukchi Sea using nonlinear Bayesian inversion

Warner, Graham Andrew 09 September 2016 (has links)
This thesis develops and applies nonlinear Bayesian inversion methods for localization of bowhead whales and environmental characterization, with quantitative uncertainty estimation, based on acoustic measurements from a set of asynchronous single-channel recorders in the Chukchi Sea. Warping analysis is applied to estimate modal-dispersion data from airgun sources and whale calls. Whale locations and the water-column sound-speed profile (SSP) and seabed geoacoustic properties are estimated using reversible-jump Markov-chain Monte Carlo sampling in trans-dimensional inversions that account for uncertainty in the number of SSP nodes and subbottom layers. The estimated SSP and seafloor sound speed are in excellent agreement with independent estimates, and whale localization uncertainties decrease substantially when jointly-inverting data from multiple whale calls. Bowhead whales are also localized using a fixed-dimensional inversion of time-difference-of-arrival data derived using cross-correlation for the same recorders. The nonlinear localization uncertainty estimates are found to depend strongly on the source locations and receiver geometry. / Graduate
95

Beach burial of cetaceans: implications for conservation, and public health and safety

Bui, Ann January 2009 (has links)
Every year hundreds of cetaceans strand on New Zealand beaches. Options for dealing with disposal of their carcasses are few, creating significant problems for the Department of Conservation (DOC). More often than not their carcasses are buried in beaches at or just above high water mark, near where the animals have stranded. The primary objective of this thesis is to determine the effects of cetacean burial on beach sediments, and evaluate potential health and safety risks associated with this practice. A secondary objective of this thesis is to appraise the appropriateness of one location DOC has repeatedly transported cetacean carcasses to and buried within beach sediments, Motutapu Island in Waitemata Harbour. The chemical effects of cetacean burial over a six-month period are reported for two sites at which animals were buried in 2008, Muriwai and Pakiri beaches; the biological effects of this burial are reported for one of these sites, Muriwai Beach, 12 months post burial. Intertidal faunal and floral inventories are provided for six sites around Motutapu Island, and these then compared and contrasted with inventories compiled from an additional 290 intertidal sites between Whangarei Heads and Tauranga Harbour, North Island East Coast, to appraise the relative uniqueness of intertidal species diversity around Motutapu Island. At both Muriwai and Pakiri beaches, nitrogen and phosphate concentrations in surface sands changed considerably following cetacean burial, although over six months the effect was localized and elevated concentrations of these two chemicals that could be attributed to a buried carcass did not extend more than 40 m from the site of whale burial. Deep-core profiles revealed nitrogen and phosphate concentrations at and in the immediate vicinity of cetacean burial approximately six months after burial to be markedly elevated to the level of the water table, but elevated concentrations attributable to the buried carcass were not observed greater than 25 m from the site of burial. Elevated concentrations of nitrogen and phosphates in beaches persist in surface sediments for at least six months post burial. Twelve months post cetacean burial no significant difference in species richness or abundance were apparent in intertidal communities extending along transects proximal to and some distance from the Muriwai Beach carcass; there is no evidence for any significant short-term (to 12 months) biological effects of cetacean burial in beaches. Of those shores on Motutapu Island accessible by earth-moving equipment and large vessels capable of dealing with and transporting large cetacean carcasses, Station Bay appeared to be the most appropriate site for whale burial. However its small size and relatively high biological value (fairly high species richness for comparable shores between Whangarei Heads and Tauranga) renders it an inappropriate long-term option for whale burial. Other shores on Motutapu Island host some of the highest species richness of all shores surveyed between Whangarei Heads and Tauranga Harbour, rendering them entirely inappropriate locations for burying cetaceans, over and above other variables that may influence disposal location identification (such as archaeological sites, dwellings and accessibility). Motutapu Island is not considered an appropriate location for cetacean burial within beaches. Alternative disposal strategies need to be explored for dealing with cetaceans that strand on Auckland east coast beaches. Although burial is the most convenient and most economical strategy to dispose of cetacean carcass, especially in mass stranding events or when cetaceans are of large size, and the biological effects of this practice are not considered significant (for the one whale that could be studied), persistent enrichment of beach sediments with organic matter could result in prolonged persistence of pathogens in beaches, causing unforeseen risks to human health and safety. Recommendations are made to minimize possible threats to public following burial of cetaceans in beaches, until the potential health risks of burial are more fully understood.
96

Evaluating ecotourism in Mexico’s biosphere reserves – whale watching activities in the World Heritage Site of Laguna San Ignacio, Baja California Sur, Mexico, 1994-2002

Rossing, Peter 11 1900 (has links)
A descriptive case study approach and 34 indicators was used to examine the socio-economic impacts of whale watching tourism in the Laguna San Ignacio (LSI) World Heritage Site - located within the El Vizcaino Biosphere Reserve in Baja California Sur, Mexico. The framework measured both the socio-economic changes, and the economic viability of the local and regional operators. This approach led to a detailed understanding of the underlying, and often complex, inter-related factors that shaped the ecotourism development in LSI between 1994 and 2002. It identified strengths and weaknesses of current ecotourism development making it a valid tool for evaluating and improving these activities in any biosphere reserve. More specifically the objectives were to examine: 1. How existing ecotourism operations and their activities in the LSI have changed since 1994; 2. Whether these changes have made ecotourism a more viable socio-economic development alternative for the local communities; and 3. Which strategies may be useful in overcoming identified barriers to further socio-economic benefits both from existing and future ecotourism activities. The results strongly suggested that the benefits from ecotourism improved significantly between 1994 and 2002. Economically this was reflected in growth of visitor numbers (50%), employment (100%) and local and regional revenue approximately 70% (or 55% in real terms adjusting for inflation). Social benefits were seen in more cooperation among previous antagonistic stakeholders; a wider distribution of ecotourism benefits; some improvement in living standards and increasing local support for the Reserve. Politically, local stakeholders became more empowered through involvement in tourism related management activities. The viability of the local and regional operators also improved significantly as they became more sophisticated in their product offerings, enhanced their facilities and gained a market share of ecotourism relative to the foreign operators. These improvements were particular true for the operators that sold package tours. However, the analyses also revealed a number of barriers with the most important ones being: • Unresolved historic land use conflicts over rights to land with ecotourism possibilities; • Lack of activities diversification possibilities outside the tourism season; • Stagnating visitor numbers; • Uneven business skills among operators; • Poor marketing and promotional efforts; • Insufficient ecotourism infrastructure; • A proposed ecotourism tax; • Low profit margin of the ecotourism operators; and • Lack of funding for further investments To alleviate these threats and barriers 13 general strategies were identified. An elaboration of these resulted in 39 concrete operational strategies on how potentially to implement them.
97

History, Trauma and Healing in Linda Hogan¡¦s People of the Whale

Chiang Lin, Chien-yi 27 August 2010 (has links)
This thesis seeks to examine history, trauma and healing in Linda Hogan¡¦s People of the Whale. For Native American people, the disease is not conceived of a pure pathology but bears on inscriptions of colonial power and disharmony with Nature. Through the body of the protagonist Thomas, Hogan articulates the Makah¡¦s silenced history and trauma. I argue that Thomas¡¦s body epitomizes the once ill and then healed earth and tribal society. This thesis proceeds in five chapters. The first chapter is an introduction. Chapter Two, ¡§Violence and Tribal Histories,¡¨ sheds light on the historical context of the Northwest Coast Makah people on which Hogan bases her novel People of the Whale. The harsh impacts of colonialism on the Makahs, as Hogan¡¦s collaborative work Sightings with Brenda Peterson reveals, persist to the present. Chapter Three, entitled ¡§Representing Traumatic Experiences,¡¨ reads Thomas¡¦s silent body as a site of his tribe¡¦s repressed colonial history. Appropriating notions from Michel de Certeau and Paula Gunn Allen, I ask how Thomas¡¦s individual tortured body conflates with another body, ¡§the altered earth,¡¨ to disclose the act of colonial violence. Thomas¡¦s oblivion of ancestral ¡§body language¡¨ and ill sense of alienation exemplify his tribe¡¦s collective ill relationship with Nature. Chapter Four, entitled ¡§A Healing Journey,¡¨ illustrates how Thomas retrieves the tribal ways to reestablish his relationship with Nature. The tribal ways, stories and memories stored in his body are never lost but simply forgotten. In N. Scott Momaday¡¦s words, it is the ¡§memory in the body¡¨ or the ¡§blood memory¡¨ that preserves what the white colonizers have erased. For Native American people, this memory enacts healing. Thomas learns to regain the ancestral ¡§body language¡¨ and in so doing recovers from his ailment and reconnects himself with his tribe, his past, and the natural world. The bodily experiences function as crucial stimuli to awaken memories buried in his body. Thomas¡¦s retrieval of ¡§body language¡¨ is an articulation of his tribe¡¦s long-silenced voice. Chapter Five, the conclusion, recapitulates the main themes of this thesis and their import. Utilizing a mythical ending of Thomas¡¦s afterlife living in the tribe and then underneath the ocean¡Xa symbol of ¡§great being¡¨¡XHogan shapes a ¡§universal¡¨ and ¡§communal body¡¨ as a powerful challenge to resist against globalization and the colonial project. People of the Whale is an anchor text in which Hogan envisions a will and a hope that Native American values will emerge and prevail.
98

A Study on the Principles for the Operation and Management of the Dolphin and Whale Watching Industry along the Eastern Coast of Taiwan

Kuo, Yen-Ruey 12 September 2001 (has links)
ABSTRACT Title: A Study on the Principles for the Operation and Management of the Dolphin and Whale Watching Industry along the Eastern Coast of Taiwan Author: Yen-Ruey Kuo The dolphin and whale watching industry has become one of the most thriving tourism industries in Taiwan in recent years, and as such, a comprehensive system of operation and management is required to help secure its sustainable development. This thesis focuses on the eastern coast of Taiwan where dolphin and whale watching first developed earliest in Taiwan and where the largest portion of operators in the business is located. Based on personal interviews following carefully-designed questionnaires with local experienced operators, skippers and narrators, this thesis studies and analyzes the present conditions of local operations and management within four aspects of the development of the industry, namely marketing strategies, environmental and ecological protection, social justice and general institutional issues. It also presents suggestions concerning sustainable development in the dolphin and whale watching industry along the eastern coast of Taiwan. Finally, according to the suggestions provided by operators and managers, domestic and foreign references and/or personal observation, the thesis proposes fifteen principles for the sustainable development for the dolphin and whale watching industry. The first ever for Taiwan, these principles are believed to be invaluable in further developing the required indicators and/or guidelines for the sustainable development of the dolphin and whale watching industry in Taiwan.
99

Evaluating ecotourism in Mexico’s biosphere reserves – whale watching activities in the World Heritage Site of Laguna San Ignacio, Baja California Sur, Mexico, 1994-2002

Rossing, Peter 11 1900 (has links)
A descriptive case study approach and 34 indicators was used to examine the socio-economic impacts of whale watching tourism in the Laguna San Ignacio (LSI) World Heritage Site - located within the El Vizcaino Biosphere Reserve in Baja California Sur, Mexico. The framework measured both the socio-economic changes, and the economic viability of the local and regional operators. This approach led to a detailed understanding of the underlying, and often complex, inter-related factors that shaped the ecotourism development in LSI between 1994 and 2002. It identified strengths and weaknesses of current ecotourism development making it a valid tool for evaluating and improving these activities in any biosphere reserve. More specifically the objectives were to examine: 1. How existing ecotourism operations and their activities in the LSI have changed since 1994; 2. Whether these changes have made ecotourism a more viable socio-economic development alternative for the local communities; and 3. Which strategies may be useful in overcoming identified barriers to further socio-economic benefits both from existing and future ecotourism activities. The results strongly suggested that the benefits from ecotourism improved significantly between 1994 and 2002. Economically this was reflected in growth of visitor numbers (50%), employment (100%) and local and regional revenue approximately 70% (or 55% in real terms adjusting for inflation). Social benefits were seen in more cooperation among previous antagonistic stakeholders; a wider distribution of ecotourism benefits; some improvement in living standards and increasing local support for the Reserve. Politically, local stakeholders became more empowered through involvement in tourism related management activities. The viability of the local and regional operators also improved significantly as they became more sophisticated in their product offerings, enhanced their facilities and gained a market share of ecotourism relative to the foreign operators. These improvements were particular true for the operators that sold package tours. However, the analyses also revealed a number of barriers with the most important ones being: • Unresolved historic land use conflicts over rights to land with ecotourism possibilities; • Lack of activities diversification possibilities outside the tourism season; • Stagnating visitor numbers; • Uneven business skills among operators; • Poor marketing and promotional efforts; • Insufficient ecotourism infrastructure; • A proposed ecotourism tax; • Low profit margin of the ecotourism operators; and • Lack of funding for further investments To alleviate these threats and barriers 13 general strategies were identified. An elaboration of these resulted in 39 concrete operational strategies on how potentially to implement them.
100

A pelagic paradox: the ecology of a top predator in an oceanic desert

Wong, Sarah, Nuk Ping 05 December 2012 (has links)
Sperm whales (Physeter macrocephalus) are widely distributed in all oceans, but principally found in areas of high primary productivity. Historically, they were whaled extensively in the Sargasso Sea and recent surveys have also found large numbers there. However, the Sargasso Sea is an oceanic gyre considered to be low in productivity. This dissertation explores the paradox of a high abundance of large top predators in a body of water once described as an “oceanic desert”. First, I compared the diet of sperm whales in the Sargasso Sea to those off Dominica, in the eastern Caribbean. Results suggested differences in trophic ecology between these two areas, with sperm whales in the Sargasso Sea feeding at a higher trophic level. Second, I examined the spatial and temporal distribution of sperm whales in the Sargasso Sea in relation to environmental variables using acoustic surveys and autonomous recording devices. Sperm whale prevalence around Kelvin seamount, part of the New England Seamount Chain, was higher in the spring compared to the winter. Habitat modeling results suggest that the mesoscale activity associated with the Gulf Stream plays an important role in sperm whale occurrence in this area, likely due to the enhancement of primary productivity in this region. Finally, I estimated the current density of sperm whales in the northwestern Sargasso Sea and compared their present distribution to their distribution during the open-boat whaling era (1775-1921). Sperm whale density in the northern Sargasso Sea is one of the highest found globally, showing that this region remains a hotspot for sperm whales. The area where sperm whale detections per unit effort is presently the highest showed little overlap with areas where whales were hunted historically. Whalers all but ignored this region except when transiting to other whaling grounds, perhaps a result of fixed whaling patterns due to the conservative use of knowledge at that time. My dissertation highlights patterns and processes that help to explain the presence and abundance of sperm whales in the Sargasso Sea and demonstrates the importance of western boundary currents, such as the Gulf Stream, to the distribution of marine top predators.

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