Schizoporella unicornis — An Alien Bryozoan Introduced into the Strait of Georgia

1970 ◽  
Vol 27 (10) ◽  
pp. 1847-1853 ◽  
Author(s):  
N. A. Powell
Keyword(s):  
British Columbia ◽  
Crassostrea Gigas ◽  
Brood Chamber ◽  
Strait Of Georgia ◽  
Breeding Female ◽  
The Past ◽  
Canadian Population

Schizoporella unicornis (Johnston, 1847) has not been recognized in British Columbia previously but is now abundant intertidally in the Strait of Georgia in association with the oyster beds that have been planted there during the past 40 years with Japanese seed of Crassostrea gigas (Thunberg). In the ovicellate Cheilostomata, the breeding female normally develops a single ovicell or brood chamber. A remarkable departure from this condition, however, is demonstrated by the multiples of ovicells occurring in the Canadian population. The occurrence of these in Japanese material of S. unicornis provides additional confirmation of the origin of the British Columbia material.

scholarly journals Abundance Trends for Hexanchus griseus, Bluntnose Sixgill Shark, and Hydrolagus colliei, Spotted Ratfish, Counted at an Automated Underwater Observation Station in the Strait of Georgia, British Columbia

2008 ◽  
Vol 122 (2) ◽  
pp. 124 ◽  
Author(s):  
Robert Dunbrack
Keyword(s):  
British Columbia ◽  
Relative Abundance ◽  
Time Lapse ◽  
Video Monitoring ◽  
Rocky Reef ◽  
Observation Station ◽  
Strait Of Georgia ◽  
The Past ◽  
Time Period ◽  
Hexanchus Griseus

Recordings from a time lapse video monitoring station on a shallow rocky reef in the Strait of Georgia, British Columbia, revealed a steep and continuous decline in the occurrence of Hexanchus griseus (Bluntnose Sixgill Shark) between 2001 and 2007, with relative abundance in 2006 and 2007 less than 1% of that in 2001. The relative abundance of another chondrichthyan, Hydrolagus colliei (Spotted Ratfish), decreased to 15% of 2004 levels in 2005 and 2006 and remained below 25% in 2007. There is no compelling explanation for these decreases. Over the past 25 years water temperatures have increased in the Strait of Georgia and there have been a number of El Niño warm water events, but diver observations of H. griseus at this site over the same time period give no indication of prior changes in abundance. Neither species is targeted by a fishery, but injuries, possibly related to hooking and entanglement, observed in 28% of individually identified H. griseus suggests this species may be taken locally as bycatch.

Diatom- and Chironomid-Inferred Eutrophication of Bouchie Lake, British Columbia

2005 ◽  
Vol 40 (4) ◽  
pp. 418-430 ◽  
Author(s):  
Markus L. Heinrichs ◽  
Brian F. Cumming ◽  
Kathleen R. Laird ◽  
J. Sanford Hart
Keyword(s):  
British Columbia ◽  
Land Use Changes ◽  
Head Capsule ◽  
Relative Increase ◽  
Nutrient Concentrations ◽  
The Past ◽  
Nutrient Levels ◽  
Lower Head ◽  
Lower Oxygen ◽  
Historical Land Use

Abstract Diatom and chironomid analysis of sediments encompassing the past 400 years from Bouchie Lake, British Columbia, suggests two distinct periods of limnological conditions. Prior to 1950 AD, Fragilaria construens and F. pinnata are the most common diatom species, and Chironomus, Procladius and Tanytarsini dominate the chironomid record. Moderately low nutrient concentrations consistent with oligo-mesotrophic lakes are inferred. From 1950, the diatom assemblage is dominated by Stephanodiscus parvus, a eutrophic indicator, whereas the chironomid communities show a relative increase in littoral taxa coincident with lower head capsule abundance. Higher nutrient levels, specifically total phosphorus, which increased from 8 µg L-1 prior to 1950 to 20 µg L-1 currently, are coincident with midge communities indicative of lower oxygen concentrations. Observed biotic changes and nutrient levels inferred from the sediment core correspond to historical land-use changes.

scholarly journals Upper-crustal structure beneath the Strait of Georgia, Southwest British Columbia

2007 ◽  
Vol 170 (2) ◽  
pp. 800-812 ◽  
Author(s):  
R. K. Dash ◽  
G. D. Spence ◽  
M. Riedel ◽  
R. D. Hyndman ◽  
T. M. Brocher
Keyword(s):  
British Columbia ◽  
Crustal Structure ◽  
Strait Of Georgia

Characterizing spatial structures of larval fish assemblages at multiple scales in relation to environmental heterogeneity in the Strait of Georgia (British Columbia, Canada)

2018 ◽  
Vol 75 (11) ◽  
pp. 1902-1914 ◽  
Author(s):  
Lu Guan ◽  
John F. Dower ◽  
Pierre Pepin
Keyword(s):  
British Columbia ◽  
Environmental Heterogeneity ◽  
Multiple Scales ◽  
Larval Fish ◽  
Critical Role ◽  
Multiscale Approach ◽  
Spatial Structures ◽  
Strait Of Georgia ◽  
Medium Scale

Spatial structures of larval fish in the Strait of Georgia (British Columbia, Canada) were quantified in the springs of 2009 and 2010 to investigate linkages to environmental heterogeneity at multiple scales. By applying a multiscale approach, principal coordinate neighborhood matrices, spatial variability was decomposed into three predefined scale categories: broad scale (>40 km), medium scale (20∼40 km), and fine scale (<20 km). Spatial variations in larval density of the three dominant fish taxa with different early life histories (Pacific herring (Clupea pallasii), Pacific hake (Merluccius productus), and northern smoothtongue (Leuroglossus schmidti)) were mainly structured at broad and medium scales, with scale-dependent associations with environmental descriptors varying interannually and among species. Larval distributions in the central-southern Strait were mainly associated with salinity, temperature, and vertical stability of the top 50 m of the water column on the medium scale. Our results emphasize the critical role of local estuarine circulation, especially at medium spatial scale, in structuring hierarchical spatial distributions of fish larvae in the Strait of Georgia and suggest the role of fundamental differences in life-history traits in influencing the formation and maintenance of larval spatial structures.

Summary of Coastal Geologic Evidence for past Great Earthquakes at the Cascadia Subduction Zone

1995 ◽  
Vol 11 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Brian F. Atwater ◽  
Alan R. Nelson ◽  
John J. Clague ◽  
Gary A. Carver ◽  
David K. Yamaguchi ◽  
...  
Keyword(s):  
British Columbia ◽  
North America ◽  
Subduction Zone ◽  
Forest Soils ◽  
Pacific Coast ◽  
Cascadia Subduction Zone ◽  
Level Change ◽  
The Past ◽  
The Pacific ◽  
Juan De Fuca

Earthquakes in the past few thousand years have left signs of land-level change, tsunamis, and shaking along the Pacific coast at the Cascadia subduction zone. Sudden lowering of land accounts for many of the buried marsh and forest soils at estuaries between southern British Columbia and northern California. Sand layers on some of these soils imply that tsunamis were triggered by some of the events that lowered the land. Liquefaction features show that inland shaking accompanied sudden coastal subsidence at the Washington-Oregon border about 300 years ago. The combined evidence for subsidence, tsunamis, and shaking shows that earthquakes of magnitude 8 or larger have occurred on the boundary between the overriding North America plate and the downgoing Juan de Fuca and Gorda plates. Intervals between the earthquakes are poorly known because of uncertainties about the number and ages of the earthquakes. Current estimates for individual intervals at specific coastal sites range from a few centuries to about one thousand years.

Factors influencing the distribution of Egregia menziesii (Phaeophyta, Laminariales) in British Columbia, Canada

1978 ◽  
Vol 56 (9) ◽  
pp. 1198-1205 ◽  
Author(s):  
D. K. Gordon ◽  
R. E. DE Wreede
Keyword(s):  
British Columbia ◽  
High Temperature ◽  
Laboratory Experiments ◽  
Algal Flora ◽  
The West ◽  
Common Component ◽  
Strait Of Georgia ◽  
Low Salinity ◽  
Factors Influencing ◽  
Juan De Fuca

Egregia menziesii (Turner) Areschoug is a common component of the algal flora along the west coast of Vancouver Island, Queen Charlotte Strait, and the Strait of Juan de Fuca but is absent from the Strait of Georgia in British Columbia, Canada. This distribution pattern was found to be correlated with temperature and salinity in that E. menziesii is not present in areas where there are seasonal periods of low salinity and high temperature. To test this correlation, field transplants of sporophytes and laboratory experiments with sporophytes and culture work were carried out. The results suggest that the distribution of E. menziesii is limited by specific combinations of salinity and temperature; it requires high salinities and temperatures less than 15 °C for its survival.

The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.)

1996 ◽  
Vol 70 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Desmond Collins
Keyword(s):  
British Columbia ◽  
Sea Cucumber ◽  
Great Difficulty ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
The Past ◽  
History Of ◽  
The Many ◽  
Life On Earth ◽  
Mistaken Identification

The remarkable “evolution” of the reconstructions of Anomalocaris, the extraordinary predator from the 515 million year old Middle Cambrian Burgess Shale of British Columbia, reflects the dramatic changes in our interpretation of early animal life on Earth over the past 100 years. Beginning in 1892 with a claw identified as the abdomen and tail of a phyllocarid crustacean, parts of Anomalocaris have been described variously as a jellyfish, a sea-cucumber, a polychaete worm, a composite of a jellyfish and sponge, or have been attached to other arthropods as appendages. Charles D. Walcott collected complete specimens of Anomalocaris nathorsti between 1911 and 1917, and a Geological Survey of Canada party collected an almost complete specimen of Anomalocaris canadensis in 1966 or 1967, but neither species was adequately described until 1985. At that time they were interpreted by Whittington and Briggs to be representatives of “a hitherto unknown phylum.”Here, using recently collected specimens, the two species are newly reconstructed and described in the genera Anomalocaris and Laggania, and interpreted to be members of an extinct arthropod class, Dinocarida, and order Radiodonta, new to science. The long history of inaccurate reconstruction and mistaken identification of Anomalocaris and Laggania exemplifies our great difficulty in visualizing and classifying, from fossil remains, the many Cambrian animals with no apparent living descendants.

Degrees of Intimacy

2002 ◽  
Author(s):  
David Ehrenfeld
Keyword(s):  
United States ◽  
British Columbia ◽  
Adult Male ◽  
Western United States ◽  
Horseback Riding ◽  
The Past ◽  
Garibaldi Provincial Park ◽  
Walking Stick ◽  
Provincial Park

When we arrived in Vancouver at the start of our vacation, the tabloid headline at the newspaper stand caught our attention. “World’s Bravest Mom,” it shrieked. We stopped to read. The story was simple; it needed no journalistic embellishment. Dusk, August 19, 1996. Mrs. Cindy Parolin is horseback riding with her four children in Tulameen, in southern British Columbia’s Okanagan region. Without warning, a cougar springs out of the vegetation, hurtling at the neck of one of the horses. In the confusion, Steven Parolin, age six, falls off his horse and is seized by the cougar. Mrs. Parolin, armed only with a riding crop, jumps off her horse and challenges the cougar, which drops the bleeding child and springs at her. Ordering her other children to take their wounded brother and go for help, Mrs. Parolin confronts the cougar alone. By the time rescuers reach her an hour later, she is dying. The cat, shot soon afterward, was a small one, little more than sixty pounds. Adult male cougars can weigh as much as 200 pounds, we learn the next day from the BC Environment’s pamphlet entitled “Safety Guide to Cougars.” We are on our way to Garibaldi Provincial Park, where we plan to do some hiking, and have stopped in the park head-quarters for information. “Most British Columbians live all their lives without a glimpse of a cougar, much less a confrontation with one,” says the pamphlet, noting that five people have been killed by cougars in British Columbia in the past hundred years. (Actually, the number is now higher; cougar attacks have become increasingly common in the western United States and Canada in recent years.) “Seeing a cougar should be an exciting and rewarding experience, with both you and the cougar coming away unharmed.”However, the pamphlet notes, cougars seem to be attracted to children as prey, possibly because of “their high-pitched voices, small size, and erratic movements.” When hiking, “make enough noise to prevent surprising a cougar . . . carry a sturdy walking stick to be used as a weapon if necessary,” and “keep children close-at-hand and under control.”

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