With increased human populations and tourism in coastal areas, there is greater potential for disturbance of marine wildlife. Having high metabolic rates, sea otters (Enhydra lutris nereis) are at risk of increased energetic costs due to disturbance. To investigate these effects, sea otter activity in response to potential disturbance stimuli was recorded over three years, at three California locations: Monterey, Moss Landing, and Morro Bay. A hidden Markov Model was developed to examine how activity varies as a function of location, group size, pup to adult ratio, kelp canopy, and occurrence of and proximity to disturbance stimuli. Results were combined with published estimates of activity-specific metabolic rates, translating activity change into energetic costs. The effects of disturbance stimuli on sea otter behavior appear location specific, and vary non-linearly with distance from disturbance stimuli. The model quantifies the distance-disturbance relationship, calculating distance at which the likelihood of disturbance is low (i.e. averaged across locations, there is <10% potential for disturbance when stimuli are >54 m away). Energetic costs (kJ) for Monterey, Moss Landing, and Morro Bay (given six small-craft approaches of 20 m for a 27.7 kg male otter in kelp, group size 10, and pup ratio 0.5) are expected to increase by 210.1 kJ ± 80.76, 160.07 kJ ± 65.24 and 58.44 kJ ± 23.66, respectively. Our analyses represent a novel approach for estimating behavioral responses and energetic costs of disturbance, furthering understanding of how human activities impact sea otters and providing a sound scientific basis for management.
|Advisor:||McDonald, Birgitte I|
|Commitee:||Connolly, Thomas P, Tinker, Tim|
|School:||San Jose State University|
|School Location:||United States -- California|
|Source:||MAI 81/4(E), Masters Abstracts International|
|Subjects:||Physiology, Conservation biology, Ecology|
|Keywords:||Anthropogenic Disturbance, Disturbance Cost, Energetic Cost, Hidden Markov Model, Marine Recreation, Sea Otter|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be