Recent Trends in the Abundance of Harbour Seals, Phoca vitulina, in British Columbia

1990 ◽  
Vol 47 (5) ◽  
pp. 992-1003 ◽  
Author(s):  
Peter F. Olesiuk ◽  
Michael A. Bigg ◽  
Graeme M. Ellis
Keyword(s):  
British Columbia ◽  
Vancouver Island ◽  
Phoca Vitulina ◽  
Primary Study ◽  
Relative Distribution ◽  
Strait Of Georgia ◽  
Queen Charlotte Islands ◽  
Harbour Seals ◽  
Recent Trends ◽  
Skeena River

Aerial censuses of harbour seals (Phoca vituiina) were conducted in the Strait of Georgia (1966–88), the lower Skeena River (1977–87), off the southwest coast of Vancouver island (1976–87), off the northeast coast of the Queen Charlotte Islands (1986), in Jervis Inlet (1987), and at the entrance to Queen Charlotte Strait (1988). The estimated number of seals in the Strait of Georgia, the primary study area, increased from 2170 in 1973 to 15 810 in 1988; the number in the lower Skeena River from 520 in 1977 to 1590 in 1987; and the number off south western Vancouver Island from 210 in 1976 to 1130 in 1987. The trends indicated that populations throughout British Columbia had been increasing at a rate of about 12.5% ∙yr−1 since 1973. Based on the density of seals in the areas surveyed, and the relative distribution of bounty and commercial kills, the total post-pupping population in British Columbia was estimated to have numbered 75 000–88 000 in 1988, compared with 9000–10 500 when the species was protected in 1970. Despite the recent increases, which probably reflect the recovery from historic kills, there was no evidence of density-dependent changes in the population growth rate.

Review: Receiver function studies in the southern Canadian Cordillera

1995 ◽  
Vol 32 (10) ◽  
pp. 1514-1519 ◽  
Author(s):  
John F. Cassidy
Keyword(s):  
British Columbia ◽  
Upper Mantle ◽  
Receiver Function ◽  
Vancouver Island ◽  
Moho Depth ◽  
Canadian Cordillera ◽  
Low Velocity ◽  
Strait Of Georgia ◽  
Low Velocity Zone ◽  
Velocity Zone

Receiver function analysis has proven to be a powerful, yet inexpensive tool for estimating the S-wave velocity structure of the crust and upper mantle beneath three-component seismograph stations in the southern Canadian Cordillera. Receiver function studies using a portable broadband seismograph array across southwestern British Columbia provided site-specific estimates for the location of the subducting Juan de Fuca plate. The oceanic crust was imaged at 47−53 km beneath central Vancouver Island, and 60–65 km beneath the Strait of Georgia. Further, these studies revealed a prominent low-velocity zone (VS = −1.0 km/s) that coincides with the E reflectors imaged ~5–10 km above the subducting plate on Lithoprobe reflection lines. The E low-velocity zone was shown to extend into the upper mantle beneath the Strait of Georgia and the British Columbia mainland, to depths of 50–60 km. Combining the receiver function and refraction models revealed a high Poisson's ratio (0.27–0.38) for this feature. The continental Moho was estimated at 36 km beneath the Strait of Georgia, and a crustal low-velocity zone associated with the Lithoprobe C reflectors beneath Vancouver Island was interpreted to extend eastward, near the base of the continental crust, to the British Columbia mainland. Analysis of data from the recently deployed Canadian National Seismograph Network demonstrates the variations in crustal thickness and complexity across the southern Canadian Cordillera, with the Moho depth varying from 35 km in the Coast Mountains, to 33 km near Penticton, to 50 km near the Rocky Mountain deformation front.

A Statistical Examination of Anisakis Larvae (Nematoda) in Herring (Clupea pallasi) of the British Columbia Coast

1955 ◽  
Vol 12 (4) ◽  
pp. 571-592 ◽  
Author(s):  
Yvonne M. M. Bishop ◽  
Leo Margolis
Keyword(s):  
British Columbia ◽  
West Coast ◽  
Maximum Level ◽  
Vancouver Island ◽  
First Year ◽  
Intensity Of Infection ◽  
The West ◽  
Strait Of Georgia ◽  
Clupea Pallasi ◽  
First Year Of Life

The presence of larval Anisakis in British Columbia herring was examined during the winter fisheries of 1950–51 and 1951–52. In the commercial catches in the Strait of Georgia the incidence was found to be between 80 and 90%. In Hecate Strait, on the west coast of Vancouver Island and in the mainland coastal area of Queen Charlotte Sound it was between 90 and 100%. The intensity of infection varied greatly in different fishing areas (i.e. in different herring populations). Generally, the maximum level of infection occurred in the Queen Charlotte Sound coastal regions, and decreased both north and south of this area. Fish on the west coast of Vancouver Island were more heavily infected than those on the east coast (Strait of Georgia). The level of infection increased with age, I-year fish (i.e. fish in their first year of life) being uninfected. The intensity of infection remained constant throughout the winter for any particular age and area and was the same for both sexes. In most areas the level of infection was a little lower in 1951–52 than in 1950–51.

Late Pleistocene history and geomorphology, southwestern Vancouver Island, British Columbia

1979 ◽  
Vol 16 (9) ◽  
pp. 1645-1657 ◽  
Author(s):  
Neville F. Alley ◽  
Steven C. Chatwin
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Late Pleistocene ◽  
Vancouver Island ◽  
Glacial Lakes ◽  
Small Lakes ◽  
Strait Of Georgia ◽  
Coast Mountains ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

The major Pleistocene deposits and landforms on southwestern Vancouver Island are the result of the Late Wisconsin (Fraser) Glaciation. Cordilleran glaciers formed in the Vancouver Island Mountains and in the Coast Mountains had advanced down Strait of Georgia to southeastern Vancouver Island after 19 000 years BP. The ice split into the Puget and Juan de Fuca lobes, the latter damming small lakes along the southwestern coastal slope of the island. During the maximum of the glaciation (Vashon Stade), southern Vancouver Island lay completely under the cover of an ice-sheet which flowed in a south-southwesterly direction across Juan de Fuca Strait, eventually terminating on the edge of the continental shelf. Deglaciation was by downwasting during which ice thinned into major valleys and the strait. Most upland areas were free of ice down to an elevation of 400 m by before 13 000 years BP. A possible glacier standstill and (or) resurgence occurred along Juan de Fuca Strait and in some interior upland valleys before deglaciation was complete. Glacial lakes occupied major valleys during later stages of deglaciation.

Geographic and sexual variation in the skull of Pacific coast marten (Martes americana)

1989 ◽  
Vol 67 (6) ◽  
pp. 1386-1393 ◽  
Author(s):  
Guillermo R. Giannico ◽  
David W. Nagorsen
Keyword(s):  
British Columbia ◽  
Sexual Dimorphism ◽  
Pacific Coast ◽  
Multivariate Analyses ◽  
Vancouver Island ◽  
Martes Americana ◽  
The Third ◽  
Queen Charlotte Islands ◽  
Sexual Variation ◽  
Cranial Measurements

From multivariate analyses of 25 cranial measurements, we assessed geographic and sexual variation in three island and two mainland samples of Pacific coast marten (Marten americana) from the caurina subspecies group. Three morphological groups were evident: the first from Queen Charlotte Islands, the second from Alexander Archipelago and Alaska Panhandle, and the third from Vancouver Island and the southern British Columbia coast. We concluded that the subspecies M. a. nesophila should be restricted to the Queen Charlotte Islands; Vancouver Island and southern British Columbia coastal marten are aligned with M. a. caurina. Alaskan marten showed some affinities with the americana subspecies group. The strong differentiation of M. a. nesophila is concordant with the isolation and unique selection regime of the Queen Charlotte Islands. Sexual dimorphism was most pronounced in island samples; possible explanations for this trend are discussed.

scholarly journals Seasonal Variation of Temperature and Salinity of Surface Waters of the British Columbia Coast

1953 ◽  
Vol 10 (3) ◽  
pp. 125-145 ◽  
Author(s):  
G. L. Pickard ◽  
D. C. McLeod
Keyword(s):  
British Columbia ◽  
West Coast ◽  
Sea Water ◽  
Deep Ocean ◽  
Vancouver Island ◽  
Early Summer ◽  
The West ◽  
Queen Charlotte Islands ◽  
Land Drainage ◽  
Run Off

Grand monthly means of daily observations of surface sea-water temperature and salinity from twelve light stations along the British Columbia coast during the 13 years 1935 to 1948 have been analysed. In general the temperatures reach a minimum of 45°F. ± 1° (7.2 °C. ± 0.5°) in January and February. The maximum varies from 50° to 64°F. (10° to 18 °C.) in August. The warmest waters occur in bays protected from wind action, and the coldest waters occur in regions of turbulent mixing due to wind or strong currents. The salinity along the mainland coast is a minimum in early summer, associated with the maximum run-off from melting snow. Along the west coast of Vancouver Island the minimum occurs in mid-winter, associated with maximum precipitation which is not stored as snow in this region. At the southern and northern tip of the Queen Charlotte Islands there is little or no variation of salinity because there is no land drainage of consequence in the vicinity.In passes between Georgia Strait and the sea where the waters are mixed to homogeneity by strong tidal currents the annual variation of temperature and salinity is reduced, and in some cases entirely suppressed.On the west coast of Vancouver Island it is shown that the annual cycle is affected by the dominant winds and upwelling of deep ocean waters.

THE BIOLOGY OF CANADIAN WEEDS.: 50. Hypochoeris radicata L.

1981 ◽  
Vol 61 (2) ◽  
pp. 365-381 ◽  
Author(s):  
LONNIE W. AARSSEN
Keyword(s):  
British Columbia ◽  
Taraxacum Officinale ◽  
Vancouver Island ◽  
Biological Data ◽  
The West ◽  
Close Resemblance ◽  
Queen Charlotte Islands ◽  
Bright Yellow ◽  
Wide Range

This paper provides a summary of biological data on Hypochoeris radicata L. (spotted cat’s-ear). This weed is naturalized in Canada on both the west and east coasts but is common only on Vancouver Island, the Queen Charlotte Islands, and the adjacent mainland of British Columbia. It is adapted to a wide range of habitats such as lawns, fields and along roadsides. The species is commonly mistaken for dandelion (Taraxacum officinale Weber), fall hawkbit (Leontodon autumnalis L.) or Hypochoeris glabra L. due to the close resemblance of their bright yellow flowers. This last species is the only other member of the genus occurring in Canada and it hybridizes readily in nature with H. radicata. Several herbicides can be used to control H. radicata.

Fecundity of coho salmon (Oncorhynchus kisutch) and chum salmon (O. keta) in the northeast Pacific Ocean

1982 ◽  
Vol 60 (6) ◽  
pp. 1463-1469 ◽  
Author(s):  
Terry D. Beacham
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Vancouver Island ◽  
Northeast Pacific ◽  
Queen Charlotte Islands ◽  
Kodiak Island ◽  
Salmon Stock ◽  
Northeast Pacific Ocean

Significant regional and annual variability in fecundity of coho salmon (Oncorhynchus kisutch) and chum salmon (O. keta) in British Columbia was detected during this investigation. A Kodiak Island (Alaska) coho salmon stock was more fecund than southern stocks in British Columbia and Washington. Fecundity ranged from 2450 to 2850 eggs per female at 53.6 cm postorbital–hypural length for Vancouver Island stocks to over 4400 eggs per female for a Kodiak Island stock at the same length. Chum stocks on Vancouver Island and the Queen Charlotte Islands generally had fecundities less than 3200 eggs per female at 58.8 cm postorbital–hypural length, whereas chum of equal lengths in mainland British Columbia stocks ranged from 3200 to 3450 eggs per female. Older chum and coho were usually more fecund than younger ones, but this difference could be accounted for by differences in mean length-at-age, fecundity being related to body size.

Biomagnification of polychlorinated biphenyls in a harbor seal (Phoca vitulina) food web from the strait of Georgia, British Columbia, Canada

2012 ◽  
Vol 31 (11) ◽  
pp. 2445-2455 ◽  
Author(s):  
Donna L. Cullon ◽  
Mark B. Yunker ◽  
Jennie R. Christensen ◽  
Robie W. Macdonald ◽  
Michael J. Whiticar ◽  
...  
Keyword(s):  
British Columbia ◽  
Polychlorinated Biphenyls ◽  
Food Web ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Strait Of Georgia

Anomalous Occurrence of Carp (Cyprinus carpio) in the Marine Environment

1971 ◽  
Vol 28 (9) ◽  
pp. 1345-1347 ◽  
Author(s):  
W. E. Barraclough ◽  
D. G. Robinson
Keyword(s):  
British Columbia ◽  
Marine Environment ◽  
Surface Waters ◽  
Cyprinus Carpio ◽  
River Estuary ◽  
Vancouver Island ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Low Salinity ◽  
Carp Cyprinus Carpio

Juvenile carp (Cyprinus carpio) were caught with a surface trawl in low salinity surface waters of the Strait of Georgia, British Columbia, during July 1967. A natural environmental route is established for the possible movement of carp from the Fraser River estuary to watersheds on Vancouver Island.

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