Mortality Trend Among Young Sockeye Salmon (Oncorhynchus nerka) During Various Stages of Lake Residence

1938 ◽  
Vol 4a (3) ◽  
pp. 184-191 ◽  
Author(s):  
R. E. Foerster
Keyword(s):  
Linear Relationship ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Mortality Trend ◽  
Percentage Loss ◽  
Percentage Survival

Young sockeye salmon, marked and liberated into Cultus lake, B.C., at intervals during the year were counted as seaward migrants. A linear relationship between time in the lake and percentage survival was found for periods of from 9.5 to 3.5 months, and from this the trend in percentage loss is computed. Mortality is found to be heavy during the first few months—approximately 65.4 per cent in the first 2.5 months—decreasing, however, as the year advances and the young sockeye increase in size.

Enhancement of Sockeye Salmon (Oncorhynchus nerka) by Lake Fertilization in Great Central Lake: Summary Report

1978 ◽  
Vol 35 (12) ◽  
pp. 1580-1596 ◽  
Author(s):  
R. J. LeBrasseur ◽  
C. D. McAllister ◽  
W. E. Barraclough ◽  
O. D. Kennedy ◽  
J. Manzer ◽  
...  
Keyword(s):  
Primary Production ◽  
Food Chain ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Standing Stock ◽  
Ammonium Phosphate ◽  
Trophic Levels ◽  
Percentage Survival ◽  
Initial Hypothesis ◽  
Lake Fertilization

Great Central Lake was treated with ca. 1001 of commercial grade fertilizer (ammonium nitrate and ammonium phosphate) annually from 1970 through 1973. Limnological parameters and sockeye salmon (Oncorhynchus nerka) juveniles and adults were monitored from 1969 through 1976 to test the hypothesis that increasing the supply of inorganic nutrients in an ultraoligotrophic lake would increase production at succeeding trophic levels. Rates of change and linkages between different elements of the food chain leading to juvenile sockeye salmon were identified. During fertilized years mean summer primary production increased fivefold, zooplankton standing stock increased 9 times, the percentage survival from estimated potential egg deposition to juvenile sockeye increased 2.6 times, while mean stock size of adult sockeye increased from < 50 000 to > 360 000. Adult sockeye returning to an adjacent untreated lake also increased in abundance. The data for the 8-yr period support the initial hypothesis, but the dominant processes affecting production and interrelationships between different trophic levels in different years remain masked. Key words: food chain, limnology, sockeye salmon, primary production, zooplankton, eutrophication, lake fertilization, enhancement

On the Relation of Adult Sockeye Salmon (Oncorhynchus nerka) Returns to Known Smolt Seaward Migrations

1954 ◽  
Vol 11 (4) ◽  
pp. 339-350 ◽  
Author(s):  
R. E. Foerster
Keyword(s):  
Multiple Regression ◽  
Negative Correlation ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Average Weight ◽  
Actual Number ◽  
Average Percentage ◽  
Residual Variability ◽  
Percentage Survival

Data were obtained from Cultus Lake giving (a) the number of seaward migrating smolts each year from 1927 to 1944, (b) their mean length and weight, and (c) the number of adults from each smolt migration which returned in the spawning escapement to the lake. These indicate a negative correlation –.5;24, (P < 0.05) between number of smolts and percentage return of adults. By multiple regression this is shown to be related almost wholly to the size of the smolts. With an increase in average weight of smolts from 4 to 10 grams, their average percentage survival is tripled.Smolt size and numbers together account for about 60 per cent of the variation in actual number of adult salmon which arrive at the lake. The residual variability could not be definitely related to available qualitative indices of fishing intensity or duration.

Resumption of anadromy or straying? Origins of Sockeye Salmon Oncorhynchus nerka in the Elwha River

2021 ◽  
Author(s):  
Thomas P. Quinn ◽  
George R. Pess ◽  
Ben J.G. Sutherland ◽  
Samuel J. Brenkman ◽  
Ruth E. Withler ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Elwha River

Alternative Recruitment Models of Adams River Sockeye Salmon, Oncorhynchus nerka

1987 ◽  
Vol 44 (9) ◽  
pp. 1551-1561 ◽  
Author(s):  
Jeremy S. Collie ◽  
Carl J. Walters
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Status Quo ◽  
Management Policy ◽  
Best Management ◽  
Interaction Terms ◽  
Ricker Model ◽  
The Status ◽  
Stock Recruitment ◽  
High Yields

Despite evidence of depensatory interactions among year-classes of Adams River sockeye salmon (Oncorhynchus nerka), the best management policy is one of equal escapement for all year-classes. We fit alternative models (Ricker model and Larkin model) to 32 yr of stock–recruitment data and checked, using simulation tests, that the significant interaction terms in the Larkin model are not caused by biases in estimating the parameters. We identified a parameter set (Rationalizer model) for which the status quo cyclic escapement policy is optimal, but this set fits the observed data very poorly. Thus it is quite unlikely that the Rationalizer model is correct or that the status quo escapement policy is optimal. Using the fitted stock–recruitment parameters, we simulated the sockeye population under several management policies. The escapement policy optimal under the Ricker model is best overall because of the high yields if it should be correct. If the three stock–recruitment models are equally likely to be correct, the simulations predict that adopting a constant-escapement policy would increase long-term yield 30% over the current policy and that an additional 15% increase in yield could be obtained if the policy were actively adaptive.

Reduced growth in wild juvenile sockeye salmon Oncorhynchus nerka infected with sea lice

2017 ◽  
Vol 91 (1) ◽  
pp. 41-57 ◽  
Author(s):  
S. C. Godwin ◽  
L. M. Dill ◽  
M. Krkošek ◽  
M. H. H. Price ◽  
J. D. Reynolds
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Sea Lice

Validation of daily increments and a marine-entry check in the otoliths of sockeye salmon Oncorhynchus nerka post-smolts

2015 ◽  
Vol 87 (1) ◽  
pp. 169-178 ◽  
Author(s):  
C. Freshwater ◽  
M. Trudel ◽  
T. D. Beacham ◽  
C.-E. Neville ◽  
S. Tucker ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Daily Increments

Biochemical Studies on Sockeye Salmon During Spawning Migration: XI. The Free Histidine Content of the Tissues

1960 ◽  
Vol 17 (3) ◽  
pp. 347-351 ◽  
Author(s):  
J. D. Wood ◽  
D. W. Duncan ◽  
M. Jackson
Keyword(s):  
Amino Acid ◽  
Sockeye Salmon ◽  
Alimentary Tract ◽  
Oncorhynchus Nerka ◽  
The Other ◽  
Spawning Migration ◽  
Fraser River ◽  
Initial Value ◽  
Spawning Grounds ◽  
Biochemical Studies

During the first 250 miles (400 km) of spawning migration of Fraser River sockeye salmon (Oncorhynchus nerka) the free histidine content of the muscle, alimentary tract, and head+skin+bones+tail decreased to a small fraction of the initial value. A further decrease occurred in the levels of this amino acid in the alimentary tract during the subsequent 415-mile (657-km) migration to the spawning grounds, no change being observed with the other tissues. Comparatively small changes in free histidine were found with heart, spleen, liver, kidney and gonads during migration.

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