scholarly journals Improving Terminal Abundance Estimates of Spring- and Summer-run Age 52 Fraser River Chinook Salmon by Incorporating a Second CPUE Dataset from the Albion Test Fishery

2019 ◽  
pp. 148-151
Author(s):  
Brittany Jenewein ◽  
Karen Rickards
Keyword(s):  
Chinook Salmon ◽  
Fraser River ◽  
Abundance Estimates

Pacific salmon and Pacific herring mortalities in the Fraser River plume caused by river lamprey (Lampetra ayresi)

1995 ◽  
Vol 52 (3) ◽  
pp. 644-650 ◽  
Author(s):  
Richard J. Beamish ◽  
Chrys-Ellen M. Neville
Keyword(s):  
Chinook Salmon ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
River Plume ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Abundance Estimates ◽  
River Lamprey

River lamprey (Lampetra ayresi) enter the Strait of Georgia from the Fraser River and feed almost exclusively on Pacific herring (Clupea harengus) and salmon (Oncorhynchus spp.). Although the major prey of river lamprey is Pacific herring, the greater effect of lamprey predation was on the populations of chinook (O. tshawytscha) and coho (O. kisutch) salmon. In 1990 and 1991, river lamprey killed a minimum of 20 million and 18 million chinook salmon, respectively, and a minimum of 2 million and 10 million coho salmon in the same years. In 1991, river lamprey in the Fraser River plume killed an equivalent of approximately 65 and 25% of the total Canadian hatchery and wild production of coho and chinook salmon, respectively. These estimates are probably low because river lamprey also feed in other areas and the abundance estimates are conservative. These high mortality rates indicate that river lamprey predation must be considered as a major source of natural mortality of chinook and coho salmon in the Strait of Georgia.

Susceptibility of six Fraser chinook salmon stocks to Ceratomyxa shasta and the effects of salinity on ceratomyxosis

1984 ◽  
Vol 62 (6) ◽  
pp. 1081-1083 ◽  
Author(s):  
Hilda Lei Ching ◽  
D. R. Munday
Keyword(s):  
Chinook Salmon ◽  
Drainage System ◽  
Infected Fish ◽  
Estuarine Environment ◽  
Fish Stock ◽  
Fraser River ◽  
Time Of Death ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook ◽  
High Level

Juvenile chinook salmon representing six stocks from the Fraser River drainage system were tested for susceptibility to the myxozoan pathogen, Ceratomyxa shasta. Of the six stocks tested, three were collected from the Nechako, Quesnel, and Clearwater rivers and three were hatchery stocks originating from Slim Creek and the Bowron and Birkenhead rivers. Of 302 fish exposed in August 1982, 95% became infected and died of ceratomyxosis. Susceptibility was high and time of death varied with the fish stock. High river temperatures during the 10 days of exposure and a high level of abundance of infectious C. shasta contributed to high mortalities of fish. Results of maintenance of infected fish in seawater indicated that ceratomyxosis is not attenuated and fish will continue to die after entering the estuarine environment.

Bioconcentration of Chlorophenols by Early Life Stages of Fraser River Pink and Chinook Salmon (Oncorhynchus gorbuscha, O. tshawytscha)

1988 ◽  
Vol 23 (1) ◽  
pp. 88-99 ◽  
Author(s):  
James A. Servizi ◽  
Robert W. Gordon ◽  
John H. Carey
Keyword(s):  
Chinook Salmon ◽  
Pink Salmon ◽  
Paper Mill ◽  
Oncorhynchus Gorbuscha ◽  
Fraser River ◽  
Life Stages ◽  
Early Life Stages ◽  
Pulp And Paper Mill ◽  
Paper Mill Effluents ◽  
Salmon Fry

Abstract Chlorophenol content of emergent pink salmon fry from five natal spawning grounds and fingerling Chinook from the Fraser River was determined. Major Chlorophenols identified were pentachlorophenol, 2,3,4,6-tetrachlorophenol, 2,4,6-trichlorophenol and 2,4-dichlorophenol. Sources of these compounds appear to be lumber mills using chlorophenol based fungicides and pulp and paper mill effluents. Chlorophenol content was greatest in pink salmon fry from the Thompson River (58.4 ng/g total Chlorophenols). Fingerling Chinook from the Fraser River contained 3 7.7 ng/g total Chlorophenols. The 96-hr LC50 of Woodbrite 24, a chlorophenol based fungicide to pink salmon during the egg-to-fry stage was determined to be in the 100 to 150 ug/L range. This range is about 100 times higher than average levels reported for Fraser River water.

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 Modelling salmon migration as a mixture problem

2019 ◽  
Vol 76 (6) ◽  
pp. 856-870 ◽  
Author(s):  
Skip McKinnell
Keyword(s):  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Simulated Data ◽  
Columbia River ◽  
Single Pulse ◽  
Model Complexity ◽  
Fraser River ◽  
The Individual ◽  
Large Adult

Pulses of abundance in salmon migrations can arise from single populations arriving at different times, from multiple populations with different timing characteristics, or as a combination of these. Daily observations typically record an aggregate measure of abundance passing some location rather than the abundances of the individual components. An objective method is described that partitions a compound migration into its component parts by exploiting differences in the characteristics of each pulse. Simulated data were used to demonstrate when greater model complexity may be desirable. Three case studies of increasing complexity (Chilko Lake sockeye salmon smolts (Oncorhynchus nerka), large adult Columbia River Chinook salmon (Oncorhynchus tshawytscha), Fraser River salmon test fishery) demonstrate how the model can be applied in practice. Results indicated that Chilko Lake smolts rarely emigrate to sea as a single pulse, that the dates used to distinguish the spring run of Chinook salmon in the Columbia River may be overestimating its abundance, and that pulses of sockeye salmon abundance in a Fraser River ocean test fishery in 2014 may have arisen from some factor other than population composition.

scholarly journals Evaluation of Long-Term Mark-Recapture Data for Estimating Abundance of Juvenile Fall-Run Chinook Salmon on the Stanislaus River from 1996 to 2017

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Tyler Pilger ◽  
Matthew Peterson ◽  
Dana Lee ◽  
Andrea Fuller ◽  
Doug Demko
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Estimation Method ◽  
Central Valley ◽  
Mark Recapture ◽  
Important Species ◽  
Trap Efficiency ◽  
Monitoring Programs ◽  
Abundance Estimates

Conservation and management of culturally and economically important species rely on monitoring programs to provide accurate and robust estimates of population size. Rotary screw traps (RSTs) are often used to monitor populations of anadromous fish, including fall-run Chinook Salmon (Oncorhynchus tshawytscha) in California’s Central Valley. Abundance estimates from RST data depend on estimating a trap's efficiency via mark-recapture releases. Because efficiency estimates are highly variable and influenced by many factors, abundance estimates can be highly uncertain. An additional complication is the multiple accepted methods for how to apply a limited number of trap efficiency estimates, each from discrete time-periods, to a population’s downstream migration, which can span months. Yet, few studies have evaluated these different methods, particularly with long-term monitoring programs. We used 21 years of mark-recapture data and RST catch of juvenile fall-run Chinook Salmon on the Stanislaus River, California, to investigate factors associated with trap efficiency variability across years and mark-recapture releases. We compared annual abundance estimates across five methods that differed in treatment of trap efficiency (stratified versus modeled) and statistical approach (frequentist versus Bayesian) to assess the variability of estimates across methods, and to evaluate whether method affected trends in estimated abundance. Consistent with short-term studies, we observed negative associations between estimated trap efficiency and river discharge as well as fish size. Abundance estimates were robust across all methods, frequently having overlapping confidence intervals. Abundance trends, for the number of increases and decreases from year to year, did not differ across methods. Estimated juvenile abundances were significantly related to adult escapement counts, and the relationship did not depend on estimation method. Understanding the sources of uncertainty related to abundance estimates is necessary to ensure that high-quality estimates are used in life cycle and stock-recruitment modeling.

Bioconcentration of Chlorophenols by Juvenile Chinook Salmon (Oncorhynchus tshawytscha) Overwintering in the Upper Fraser River: Field and Laboratory Tests

1988 ◽  
Vol 23 (1) ◽  
pp. 100-113 ◽  
Author(s):  
I. H. Rogers ◽  
J. A. Servizi ◽  
C. D. Levings
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Cold Water ◽  
Pulp Mill ◽  
Wood Preservative ◽  
Fraser River ◽  
Reference Sites ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook ◽  
River Fish

Abstract Juvenile chinook salmon were sampled from August 1986 to March 1987 at stations near Prince George and Quesnel, influenced by sewage and pulp mill discharges. Maximum densities of 0.2 fish·mࢤ2 were recorded. Salmon were collected at reference sites in November 1986 and at Agassiz in April 1987. Fingerling chinook were exposed at 0.7°C to a commercial wood preservative containing 2,3,4,6 - tetrachlorophenol (TeCP) and pentachlorophenol (PCP) in the laboratory to simulate winter conditions in the upper Fraser River. Fish exposed for 62 days to 2 ug·Lࢤ1 contained a mean of 224 ng·gࢤ1 TeCP and 431 ng·gࢤ1 PCP. Chlorophenol uptake in feral fish was low. However, 3,4,5-trichloro-guaiacol levels to 304 ng·gࢤ1 and tetrachloroguaiacol values to 136 ng·gࢤ1 were measured in March. Fish from Agassiz, 518 km downstream of Quesnel, also contained these two substances. Thus chinook salmon can bioconcentrate persistent chlorophenols and chloroguaiacols directly from cold water (< 1°C). The biological consequences are uncertain.

Extensive use of the Fraser River basin as winter habitat by juvenile chinook salmon (Oncorhynchus tshawytscha)

1991 ◽  
Vol 69 (7) ◽  
pp. 1759-1767 ◽  
Author(s):  
C. D. Levings ◽  
R. B. Lauzier
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Water Channel ◽  
Fraser River ◽  
Winter Habitat ◽  
Mean Size ◽  
System Data ◽  
The Mean ◽  
Juvenile Chinook ◽  
Stream Type

Habitat in the low-water channel of the mainstem Fraser River and larger tributaries during winter may be an unappreciated factor influencing production of stream-type chinook salmon (Oncorhynchus tshawytscha) in this system. Data from electrofishing surveys showed that shorelines were used by juvenile chinook from river km 110 to km 770. Almost the entire mainstem was therefore probably winter habitat, and major tributaries such as the Thompson, Quesnel, and Nechako rivers were also used. Estimated chinook density on the mainstem Fraser increased with distance upstream (maximum 0.30 m−2 at km 750 (Prince George)), but the highest density (0.99 m−2) in the surveys was observed on the Thompson River at Spences Bridge. The mean size of juvenile chinook decreased with distance upstream on the Fraser, ranging from 97 mm at km 110 to 65 mm at km 770. Chinook juveniles were feeding on Diptera, Trichoptera, and Plecoptera in winter. Some apparent growth was observed in the lower Fraser in early winter.

Reply to the comment by Beacham and Withler on “Gene flow increases temporal stability of Chinook salmon (Oncorhynchus tshawytscha) populations in the Upper Fraser River, British Columbia, Canada”Appears in Can. J. Fish. Aquat. Sci. 66: 167–176.

2010 ◽  
Vol 67 (1) ◽  
pp. 206-208 ◽  
Author(s):  
Ryan P. Walter ◽  
J. Mark Shrimpton ◽  
Daniel D. Heath
Keyword(s):  
Temporal Variation ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Sampling Error ◽  
Fraser River ◽  
Genetic Stock ◽  
River Population ◽  
Genetic Population ◽  
Rarefaction Analysis ◽  
Temporal Variance

Beacham and Withler (2010. Can. J. Fish. Aquat. Sci. 67: 202–205) raise concerns about the experimental design and interpretation of data in the analysis of temporal genetic variation of Chinook salmon ( Oncorhynchus tshawytscha ) from the Upper Fraser River, Canada (Walter et al. 2009. Can. J. Fish. Aquat. Sci. 66: 167–176). They note that for the sampled populations, spatial genetic variance should far exceed temporal variance components based on previously published work and suggest that limited sample sizes biased our results by confounding sampling error with temporal variation. Here, we perform a rarefaction analysis by randomly removing up to 50% of the individuals from sample sites, yet the pattern of temporal versus spatial variation is similar to that reported in our original paper. We reiterate that caution should be applied to the interpretation of migration rates estimated from assignment tests, yet the absolute magnitude of our migration estimates was not central to the goals of the original paper. Although Beacham and Withler raise important points on the validation of genetic stock identification analyses, our analyses of temporal variation in genetic population structure in the Upper Fraser River population likely differ due to demographic differences between the timing of sampling of their earlier work versus our analyses.

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