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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.
11

The effects of tourism on the behaviour of the New Zealand fur seal (Arctocephalus forsteri)

Cate, Jenipher Rose January 2013 (has links)
The demand by ecotourism for easily accessible wildlife encounters has increased the need for regulations to minimise negative effects of tourism on towards marine mammals. High levels of human interaction could have serious consequences for recovering populations of New Zealand fur seals (Arctocephalus forsteri). By monitoring behavioural shifts in reactions to human disturbance, the aim of this study was to determine how disturbance by tourism is affecting the behaviour of the New Zealand fur seals. Fur seal breeding colonies, haul-outs, and a pup nursery were studied on the South Island to determine the level of disturbance. Data collected in this study can be used towards improving monitoring regimes to mitigate negative effects of anthropogenic disturbance. I first used behavioural observations to assess a seal’s behaviour in response to different types of tourist activities. Next, I examined changes in New Zealand fur seal behaviour as a result of visits to colonies by tourist boats. To quantify the response of fur seals to tourist boats, experimental boat approaches were conducted using a before, during, and after instantaneous scan sampling method at two breeding colonies (one with high vessel traffic and one with none). Impact of noise was also investigated using a loud speaker to mimic local harbour tours. Lastly, behavioural observations on seal pups at a nursery were conducted comparing pup behaviour in the presence and absence of tourism along with variable intensities of tourist behaviour. My observations suggest that seal behaviour was significantly different between sites with and without tourist visits. The type of tourism had a significant effect on the behavioural state of seals, with animals more active when there were people walking in the colonies. There were also signs of habituation in some of the study colonies. Since each colony varied in the type of tourism it experienced, it is possible that it is not only the level of tourism that is important but also the type of tourism that has a significant role in eliciting short-term behavioural shifts. Observations from a tour boat revealed an increase in the percentage of seals reacting when vessels were close to the shore. This distance effect was overridden and reactions were greater, however, when tours included commentary via an external speaker. The effects of both distance and noises were significantly different between colonies with high and low levels of tourist visits. Due to the overlap of peak tourist visits with fur seal breeding season, these animals are at their most vulnerable when companies are in peak operation. Finally, as with adults, pup behaviour was also significantly affected by tourism presence. Periods of inactivity and awareness increased in the presence of tourists, which is indicative of disruption of “play” and movement towards more vigilant behaviour. Despite the significant effects of tourist visits I found in this study, there was large variation in the degree of responses in different populations of the fur seal. This variation is thought to be due, in part, by the level of desensitisation, especially at locations with high or continual tourism pressures. This study also provides evidence that fur seal pups subject to human disturbance will alter their behaviour, shifting from active (when people are not around) to inactive and more aware (with increased disturbance). The results presented suggest such visits are not without consequences and that animals can be disturbed by human interactions. Therefore, measures should be taken at all seal colonies used in tourism ventures to mitigate any negative long-term effect on the fur seal populations.
12

Incorporating model selection and decision analysis into population dynamics modeling /

Ward, Eric John, January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 127-139).
13

Using a Geospatial Approach to Evaluate the Impacts of Shipping Activity on Marine Mammals and Fish in Arctic Canada

Joyce, Jenna 14 June 2018 (has links)
A loss in sea ice cover, primarily attributed to climate change, is increasing the accessibility and navigability of the Arctic Ocean. This increased accessibility of the Canadian Arctic, and in particular the Northwest Passage, presents important global and national shipping and development opportunities. However, increased shipping in the region also present challenges related to the environmental sustainability, sovereignty and safety, and cultural sustainability. The Low Impact Shipping Corridors (the Corridors) is currently the foundational framework for governing ship traffic within the Canadian Arctic. However, the Corridors were largely established based on historic traffic patterns and thus they do not fully consider important areas for marine mammals and fish in the region. This research addresses this important research gap by spatially identifying important areas for marine mammals and fish in the Kitikmeot region of Nunavut using both Traditional Knowledge and western science, evaluating ship tracks from 1990-2015, and geospatially identifying and evaluating areas of potential disturbance for marine mammals and fish related to vessel noise from different ship types transiting the Corridors within the study region. The results of this study indicate that all vessel types have the potential to cause behavioural disturbance to marine mammals and fish when navigating through these important wildlife areas, and that louder vessels (i.e. Tanker ships) travelling outside of these important wildlife areas have a greater potential to cause behavioural disturbance to marine mammals and fish than quieter vessels (i.e. Pleasure Crafts). The results also indicate that vessels navigating through certain regions of the Kitikmeot have a higher potential to cause behavioural disturbances in these species, including through the Gulf of Boothia, Franklin Strait, Rae Strait, Rasmussen Basin, and Bathurst Inlet.
14

O papel dos impactos antrópicos nos processos locais e padrões globais de extinção em cetáceos / The role of anthropogenic impacts on local process and global patterns of extinction in cetaceans

Araújo, Claryana Costa 20 March 2015 (has links)
Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-06-09T17:40:11Z No. of bitstreams: 2 Tese - Claryana Costa Araújo - 2015.pdf: 2174515 bytes, checksum: 2d205f31fba2cbb199ef183432b131d4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-06-10T11:55:33Z (GMT) No. of bitstreams: 2 Tese - Claryana Costa Araújo - 2015.pdf: 2174515 bytes, checksum: 2d205f31fba2cbb199ef183432b131d4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-06-10T11:55:33Z (GMT). No. of bitstreams: 2 Tese - Claryana Costa Araújo - 2015.pdf: 2174515 bytes, checksum: 2d205f31fba2cbb199ef183432b131d4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-03-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The population of humpback dolphins Sousa chinensis that resides in the eastern Taiwan Strait (ETS) is geographically and genetically isolated from populations inhabiting the coastal waters of mainland China and appears to be facing unsustainable levels of human threats. Using VORTEX 9.99b, we modeled the viability of this Critically Endangered population under the present conditions as well as under realistic additional threat scenarios. We examined 6 different levels of bycatch mortality, 3 scenarios of habitat loss/degradation, and scenarios in which these threats were experienced together. Under the baseline (present) scenario, the population exhibited a decreasing growth rate and was predicted to be smaller than the initial population size in more than 76% of all model runs. In all scenarios with additional threats, the proportion of model runs in which population size was smaller than the initial size varied from 77.1 to 92.6%. Over the short term, fisheries-related mortality appears to have a more obvious impact on the population’s trajectory than habitat loss/degradation. Even minimal increases in mortality from the current baseline levels will increase the probability of extinction of this population. Due to the fragile situation of ETS humpback dolphins, mitigation actions to reduce the current threats to this population are needed immediately. / Sem resumo.
15

Underwater vocal repertoire and their function in three ice-breeding seals in the Arctic / 北極圏に生息する氷上繁殖型アザラシ3種の水中音声レパートリーとその機能

Mizuguchi, Daisuke 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19547号 / 理博第4207号 / 新制||理||1603(附属図書館) / 32583 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 幸島 司郎, 教授 伊谷 原一, 教授 村山 美穂 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
16

Using Plankton EDNA To Estimate Whale Abundances Off The California Coast: Data Integration And Statistical Modeling

Chan, Katherine 01 June 2024 (has links) (PDF)
Understanding marine mammal populations and how they are affected by human activity and ocean conditions is vital, especially in tracking population declines and monitoring endangered species. However, tracking marine mammal populations and their distribution is challenging due to difficulties in observation and costs. Using surrounding plankton environmental DNA (eDNA) has the potential to provide an indirect measure of monitoring cetacean abundances based on ecological associations. This project aims to apply statistical methods to assess the relationship of visual abundances of common species of baleen whales with amplicon sequence variants (ASV) of plankton eDNA samples from the NOAA-CalCOFI Ocean Genomics (NCOG) project. Modeling this relationship of eDNA with marine mammal sightings may greatly aid the ability to predict the abundance of whales in the ocean. There are several key challenges associated with the analysis of this NCOG data. Plankton eDNA samples are an example of compositional data, where the proportions of each ASV must sum to one; this provides a challenging constraint for statistical analysis and interpretation. High dimensionality (the number of parameters exceeds the observations) and sparsity (many observed zeros) of the genetic sequencing data also pose challenges in estimating parameters. Finally, the model associations should be adjusted for related factors, including seasonality and oceanographic factors, the latter of which goes beyond this project's scope. This thesis develops and fits models to estimate cetacean abundance from plankton eDNA by leveraging methods of compositional data analysis and high-dimensional regression. This project applies log-ratio data transformations and corresponding log-contrast models to address the compositional aspect of eDNA reads. Regression methods involving high-dimensional data typically rely on dimensionality reduction or regularization. This project implements both reduction and regularization through sparse partial least squares (sPLS) regression. In addition to the data modeling objective of using plankton eDNA to predict baleen whale abundances, this project also identifies ecological correlations between whale abundance and plankton eDNA.
17

Steller sea lions (Eumetopias jubatus) of Oregon and Northern California : seasonal haulout abundance patterns, movements of marked juveniles, and effects of hot-iron branding on apparent survival of pups at Rogue Reef /

Scordino, Jonathan. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.
18

The frontal system of the Antarctic Circumpolar Current : marine mammals as ocean explorers

Boehme, Lars January 2008 (has links)
In this thesis, I describe large-scale and small-scale features of the Antarctic Circumpolar Current (ACC) by merging conductivity-temperature-depth (CTD) data obtained by novel animal-borne sensors with data obtained by more conventional means. Twenty-one CTD-Satellite Relay Data Loggers (CTD-SRDLs) were attached to Southern elephant seals (Mirounga leonina) on South Georgia in 2004 and 2005. This was part of a larger international study (Southern Elephant Seals as Oceanographic Samplers; SEaOS), in which I played a major role in developing the oceanographic approach used to integrate physical data from a range of sources, and the means to link biological findings to oceanographic parameters. The development of animal-borne oceanographic sensors and their potential place within an ocean observing system is reviewed initially. Then, I describe the Series 9000 CTD-SRDL in detail, discussing its performance in the lab and during two field experiences with Southern elephant seals and Weddell seals (Leptonychotes weddellii ). Following this, a detailed study of the ACC frontal system in the South Atlantic is presented that uses merged Argo float data and CTD-SRDL data. The structure of the frontal field revealed by this unique dataset is examined, and unprecedented insight into its variability is obtained. Amongst the important findings is that, contrary to most climate models, our in situ data suggest a northward shift of the ACC east of 40W in 2004 and 2005 compared to previous work. Next, two CTD-SRDL sections are presented to identify the locations of the ACC fronts across Drake Passage, and an empirical relationship between upper ocean temperature and baroclinic mass transport is used to determine the transport through Drake Passage at the times of the sections. This technique is a powerful complement to more conventional means of data collection in this region, especially given the ability of the seals to conduct "sections" at times when ship-based fieldwork is logistically most challenging, i.e. in the winter time. The CTD-SRDLs do not only record hydrographic data, but simultaneously record seal movements and diving behavior. This enables insight to be obtained on the behavioral and physiological responses of Southern elephant seals to spatial environmental variability throughout their circumpolar range. The resulting energetic consequences of these variations could help explain recently observed spatially varying population trends. With a stable population at South Georgia and declining populations at Kerguelen and Macquarie Island. This study also highlights the benefits to the sensorcarrying animals themselves by showing the usefulness of this approach in examining the sensitivity of top predators to global and regional-scale climate variability. More importantly, I conclude that, by implementing animal-borne sensors into ocean observing strategies, we not only gain information about global ocean circulation and enhance our understanding of climate and the corresponding heat and salt transports, but at the same time we increase our knowledge about ocean’s top predators, their life history and their sensitivity to climate change.
19

Marine mammal behavior response to sonars, a review

Linderhed, Anna January 2013 (has links)
During the last decades the problems caused by anthropogenic sound and noise in oceans have been recognized in public, by governments, and military. With the use of active sonar, different choices can be made to minimize the risk of damaging or disturbing marine mammals. For this purpose knowledge of sonar disturbance is crucial. There are methods for time or area planning, i.e. when and where to use active sonars, to avoid marine mammals. The purpose of this work is to find information in literature on marine mammal behaviour reactions to the sound of sonar pings, and to evaluate which of two different behavioural models used in risk assessment programs, the “varying response” model and the “avoidance” model, is more correct to use. Main focus is on sonars and marine mammals residing in Sweden, i.e. the harbour porpoise, grey seal, harbour seal and ringed seal. Behavioral results from other research areas such as bycatch, environmental, and strandings, together with other sound sources than sonars and other species, provide a broader picture of the situation in noisy oceans. For the harbor porpoise the “avoidance” model works well. It is a very shy species, which flees fast and far when it comes in contact with new things. With the seals however the “avoidance” model is probably less good, since their responses to sonar differ rather much. Hence, for these taxa we recommend to use the “various” model that takes into account such varying responses.
20

Olfactory discrimination ability of South African fur seals (Arctocephalus pusillus) for enantiomers

Kim, Sunghee January 2012 (has links)
The sense of smell in marine mammals is traditionally thought to be poor. However, increasing evidence suggests that pinnipeds may use their sense of smell in a variety of behavioral contexts including communication, foraging, food selection, and reproduction. Using a food-rewarded two-choice instrumental conditioning paradigm, I assessed the ability of South African fur seals, Arctocephalus pusillus, to discriminate between 12 enantiomeric odor pairs, that is, between odorants that are identical in structure except for chirality. The fur seals significantly discriminated between eight out of the twelve odor pairs (according to p < 0.05, with carvone, dihydrocarvone, dihydrocarveol, limonene oxide, menthol, beta-citronellol, fenchone, and alpha-pinene), and failed with only four odor pairs (isopulegol, rose oxide, limonene, and camphor). No significant differences in performance were found between the animals (p > 0.05). Cross-species comparisons between the olfactory performance of the fur seals and that of other species previously tested on the same set of odor pairs lend further support to the notion that the relative size of the olfactory bulbs is not a reliable predictor of olfactory discrimination abilities. The results of the present study suggest that sense of smell may play an important and hitherto underestimated role in regulating the behavior of fur seals.

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