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UBC Theses and Dissertations
Seasonal abundance and distribution of marine mammals in the southern Strait of Georgia, British Columbia Keple, Alison Ruth
Abstract
The Strait of Georgia is a highly productive region and among the most important marine systems in British Columbia. It is at the mouth of the Fraser River, one of the most productive river systems in North America. Marine mammals are apex predators in this system, with at least ten species using the area during all or part of the year. Line transect surveys aboard B.C. Ferries vessels were conducted from May 1, 2000 to April 30, 2001 to determine the distribution and abundance of marine mammal species in the Strait of Georgia. A total of 2,879 individuals, representing nine species, were seen in 898 sightings. Harbour seals (n = 1,629), California sea lions (n = 415), Dall's porpoise (n = 397) and Steller sea lions (n = 205) were the most frequently observed, accounting for 92% of the sightings. Pacific white-sided dolphins (n = 110), harbour porpoise (n = 71), killer whales (n = 49), gray whales (n = 2), and a minke whale were also seen during the surveys. Abundance estimates were highest in spring and lowest in winter, with a second smaller peak in abundance in autumn. Pinnipeds were estimated to consume the most prey due to high population estimates for harbour seals and large body size of adult male sea lions. Peaks in marine mammal abundances appear to coincide with seasonal physical and biological factors in the Strait of Georgia and Fraser River system that may influence the availability of prey species.
Item Metadata
Title |
Seasonal abundance and distribution of marine mammals in the southern Strait of Georgia, British Columbia
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2002
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Description |
The Strait of Georgia is a highly productive region and among the most important
marine systems in British Columbia. It is at the mouth of the Fraser River, one of the most
productive river systems in North America. Marine mammals are apex predators in this
system, with at least ten species using the area during all or part of the year. Line transect
surveys aboard B.C. Ferries vessels were conducted from May 1, 2000 to April 30, 2001 to
determine the distribution and abundance of marine mammal species in the Strait of Georgia.
A total of 2,879 individuals, representing nine species, were seen in 898 sightings. Harbour
seals (n = 1,629), California sea lions (n = 415), Dall's porpoise (n = 397) and Steller sea
lions (n = 205) were the most frequently observed, accounting for 92% of the sightings.
Pacific white-sided dolphins (n = 110), harbour porpoise (n = 71), killer whales (n = 49),
gray whales (n = 2), and a minke whale were also seen during the surveys. Abundance
estimates were highest in spring and lowest in winter, with a second smaller peak in
abundance in autumn. Pinnipeds were estimated to consume the most prey due to high
population estimates for harbour seals and large body size of adult male sea lions. Peaks in
marine mammal abundances appear to coincide with seasonal physical and biological factors
in the Strait of Georgia and Fraser River system that may influence the availability of prey
species.
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Extent |
17973800 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-09-11
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0074860
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2002-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.