Evidence of Decreasing Spatial Diversity in British Columbia Salmon Stocks

1985 ◽  
Vol 42 (5) ◽  
pp. 1033-1037 ◽  
Author(s):  
Carl J. Walters ◽  
Peter Cahoon
Keyword(s):  
British Columbia ◽  
Monitoring System ◽  
Oncorhynchus Tshawytscha ◽  
Spatial Diversity ◽  
South Coast ◽  
Monitoring Effort ◽  
Salmon Production

Escapement records indicate a severe decline since 1950 in the number of streams contributing significantly to salmon production in southern British Columbia. To account for 90% of the escapement for chinook (Oncorhynchus tshawytscha), coho (O. kisutch), pink (O. gorbuscha), and chum (O. keta), one need examine only about half as many streams now as in 1950. The deterioration has been most pronounced for coho; only 40 of 350 south coast streams now account for 80% of the recorded escapement. The apparent changes are due partly to reduced monitoring effort rather than actual stock declines, but deterioration in the monitoring system is itself a cause for major concern.

Analysis of straying variation in Alaskan hatchery chinook salmon (Oncorhynchus tshawytscha) following transplantation

1999 ◽  
Vol 56 (4) ◽  
pp. 578-589 ◽  
Author(s):  
Jeffrey J Hard ◽  
William R Heard
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Release Site ◽  
Substantial Variation

In 1976 chinook salmon (Oncorhynchus tshawytscha) gametes from the Chickamin and Unuk rivers in southeastern Alaska were transplanted 250 km to establish hatchery runs at Little Port Walter (LPW), Baranof Island. From 1977 to 1989, 1 862 058 marked smolts from 12 broods were released from LPW. Homing and straying were estimated from adult recoveries at 25 locations in Alaska and British Columbia between 1981 and 1989. Of 22 198 LPW fish recovered over this period, 21 934 (98.8%) were collected at LPW. Of 264 fish recovered elsewhere, 38.3% were within 7 km of LPW; 64.4% were within 25 km of LPW. No LPW fish were recovered from the ancestral rivers, but nine fish were recovered from rivers supporting wild chinook salmon. Straying declined with distance from the release site but varied between hatcheries and streams. Straying declined with increasing age and run size. Straying was similar between the populations but varied among broods, and analysis of straying in experimental groups provided evidence for a heritable component. Males strayed more often than females. Population, gender, run size, and recovery age interacted to produce substantial variation in straying, indicating that run composition can produce complex straying responses.

Biochemical Genetic Survey and Stock Identification of Chum Salmon (Oncorhynchus keta) in British Columbia

1987 ◽  
Vol 44 (10) ◽  
pp. 1702-1713 ◽  
Author(s):  
T. D. Beacham ◽  
A. P. Gould ◽  
R. E. Withler ◽  
C. B. Murray ◽  
L. W. Barner
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Electrophoretic Analysis ◽  
South Coast ◽  
Oncorhynchus Keta ◽  
Stock Identification ◽  
Fraser River ◽  
Genetic Method ◽  
Chum Salmon Oncorhynchus Keta ◽  
Queen Charlotte Islands

We examined genetic variability using electrophoretic analysis of 83 chum salmon (Oncorhynchus keta) stocks in British Columbia and used regional differences in genotypic frequencies of seven polymorphic loci to estimate stock compositions in a number of commercial and experimental test fisheries. Chum salmon from five regions could be discriminated: Queen Charlotte islands, north and central coast, west coast of Vancouver Island, the Fraser River and its tributaries, and the south coast (rivers draining into Johnstone Strait and the Strait of Georgia). Allelic frequencies from 33 stocks were generally stable over a period of 2 yr or more. South coast chum salmon was the dominant run migrating through upper Johnstone Strait in October 1982–85. The genetic method of stock identification provided managers with the relative proportions of Fraser River and other groups of chum salmon in a number of fisheries and allowed managers to regulate more effectively the exploitation rate of Fraser River chum salmon.

Individual variation in dispersal behaviour of newly emerged chinook salmon (Oncorhynchus tshawytscha) from the Upper Fraser River, British Columbia

1997 ◽  
Vol 54 (7) ◽  
pp. 1585-1592 ◽  
Author(s):  
M J Bradford ◽  
G C Taylor
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Population Variation ◽  
Fraser River ◽  
Movement Behaviour ◽  
Spawning Areas ◽  
Dispersal Distances ◽  
Stream Type ◽  
Downstream Movement

Immediately after emergence from spawning gravels, fry of stream-type chinook salmon (Oncorhynchus tshawytscha) populations from tributaries of the upper Fraser River, British Columbia, distribute themselves downstream from the spawning areas, throughout the natal stream, and into the Fraser River. We tested the hypothesis that this range in dispersal distances is caused by innate differences in nocturnal migratory tendency among individuals. Using an experimental stream channel, we found repeatable differences in downstream movement behaviour among newly emerged chinook fry. Fish that moved downstream were larger than those that held position in the channel. However, the incidence of downstream movement behaviours decreased over the first 2 weeks after emergence. We propose that the variation among individuals in downstream movement behaviour we observed leads to the dispersal of newly emerged fry throughout all available rearing habitats. Thus, between- and within-population variation in the freshwater life history observed in these populations may be caused by small differences in the behaviour of individuals.

scholarly journals Extreme wind regime responses to climate variability and change in the inner south coast of British Columbia, Canada

2009 ◽  
Vol 47 (1) ◽  
pp. 41-62 ◽  
Author(s):  
Dilumie S. Abeysirigunawardena ◽  
Eric Gilleland ◽  
David Bronaugh ◽  
Pat Wong
Keyword(s):  
British Columbia ◽  
Climate Variability ◽  
South Coast ◽  
Wind Regime ◽  
Climate Variability And Change ◽  
Extreme Wind

scholarly journals Principles and perils of silviculture audits

1994 ◽  
Vol 70 (1) ◽  
pp. 43-46
Author(s):  
Jordan S. Tanz ◽  
W. L. Craig Campbell
Keyword(s):  
British Columbia ◽  
Interest Groups ◽  
Monitoring System ◽  
Specific Reference ◽  
The Public ◽  
Forestry Practices

Forestry audits may be used as a means of assuring the public that forestry practices are meeting accepted standards, as part of an internal monitoring system, or as part of efforts to resolve disputes with outside interest groups. In this paper, silviculture auditing is examined with specific reference made to the situation in British Columbia. Well-established principles of financial auditing are used as the basis for a framework of principles for silviculture auditing. Ways in which these principles can be applied in practice are shown. Some of the problems with undertaking silviculture audits are briefly reviewed.

Modelling Pelagic Fish and Plankton Trophodynamics off Southwestern Vancouver Island, British Columbia

1994 ◽  
Vol 51 (8) ◽  
pp. 1737-1751 ◽  
Author(s):  
Clifford L. K. Robinson ◽  
Daniel M. Ware
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coastal Upwelling ◽  
Squalus Acanthias ◽  
Pacific Herring ◽  
Fish Production ◽  
Clupea Pallasi ◽  
Merluccius Productus ◽  
Arrival Timing

A trophodynamics model is used to estimate annual plankton and fish production for the southern British Columbia continental shelf during 1985–89. The model describes the feeding interactions among diatoms, copepods, euphausiids, juvenile and adult Pacific herring (Clupea pallasi), Pacific hake (Merluccius productus), chinook salmon (Oncorhynchus tshawytscha), and spiny dogfish (Squalus acanthias) and is forced by empirical seasonal patterns in upwelling, sea surface temperature, and solar radiation. The most important simulation results are that (1) there is an imbalance between fish consumption and euphausiid production during the summer upwelling season, (2) the biomass and arrival timing of migratory hake significantly influence plankton and fish production, and (3) about 11% of the 332 g C∙m−2∙yr−1 annual diatom production is transferred to copepods and euphausiids and 1.0% of the diatom production to fish, while 27.5% of the 11.9 g C∙m−2∙yr−1 euphausiid production is consumed by herring and hake. The high plankton and fish production on the southern British Columbia shelf is comparable with other productive coastal upwelling regions.

A Record of Pacific Herring (Clupea harengus pallasi) Feeding on Juvenile Chinook Salmon (Oncorhynchus tshawytscha) in a British Columbia Estuary

1971 ◽  
Vol 28 (12) ◽  
pp. 1921-1921 ◽  
Author(s):  
Jun Ito ◽  
R. R. Parker
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Predator Prey ◽  
Juvenile Chinook Salmon ◽  
Clupea Harengus Pallasi ◽  
Juvenile Chinook

An occurrence of Pacific herring (Clupea harengus pallasi) predation on juvenile chinook salmon (Oncorhynchus tshawytscha) is described. This is the first recorded incidence of this particular predator–prey relation.

Sign in / Sign up

Export Citation Format

Share Document