Comparison of Acoustic Population Estimates of Salmon in a Lake with a Weir Count

1986 ◽  
Vol 43 (7) ◽  
pp. 1373-1385 ◽  
Author(s):  
T. J. Mulligan ◽  
R. Kieser
Keyword(s):  
Sensitivity Analysis ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Target Strength ◽  
Population Estimates ◽  
Acoustic Methods ◽  
Acoustic Surveys

Acoustic population estimates are performed routinely in fisheries. Usually, however, they have to stand on their own merit. A unique opportunity has been exploited to compare a series of acoustic surveys with a weir count that monitors the escapement of sockeye salmon, Oncorhynchus nerka, into a lake. Each survey was analysed by three acoustic methods; the results are compared among themselves and with the weir count. A detailed sensitivity analysis looks at the possible variance and bias in each method. Finally, several methods are used to estimate the acoustic fish target strength. These estimates are compared with published target strength values.

Population Estimates of Sockeye Salmon (Oncorhynchus nerka) in a Fertilized Oligotrophic Lake

1978 ◽  
Vol 35 (6) ◽  
pp. 851-860 ◽  
Author(s):  
D. G. Robinson ◽  
W. E. Barraclough
Keyword(s):  
Survival Data ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Age Groups ◽  
Close Correlation ◽  
Oligotrophic Lake ◽  
Population Estimates ◽  
Good Resolution ◽  
Growth And Survival ◽  
Carry Over

Pelagic juvenile sockeye salmon (Oncorhynchus nerka) populations were studied in Great Central Lake, British Columbia, during 1969–76 to determine the effect of nutrient enrichment upon their growth and survival. Data for population estimates were collected concurrently by a high-frequency echosounder, and a midwater trawl whose efficiency was inversely related to ambient light above about 1.9 × 10−5 lx. Echogram counts supplemented by trawl catches yielded estimates with low variance, good resolution between age-groups, and indicated close correlation between numbers of spawners and resultant progeny within respective treatments. Survival to the fall for the treated 1969–72 brood years averaged 11.65% (range 11.11–12.81%) of potential egg deposition compared to 3.5% for the pretreatment 1968 brood year fish; 2.73 and 6.29% for the posttreatment 1974 and 1975 brood year fish. A carry-over of fertilization effects on the immediate posttreatment 1973 brood year may have induced a cyclic pattern on the survival of the two succeeding year-classes. The relatively consistent annual production of age 0+ sockeye may be due to the inherent stability of inlake spawning and incubation coupled with the low predation rates. The conservative estimate of a 2.5 increase in survival relative to the natural level indicates a positive response to enhanced feeding conditions caused by the fertilization of this oligotrophic lake. Key words: sockeye, survival, Great Central Lake, fertilization, enhancement, acoustic estimates, townet efficiency

Hydroacoustic Estimates of Adult Sockeye Salmon (Oncorhynchus nerka) in Lake Washington, 1972–75

1979 ◽  
Vol 36 (9) ◽  
pp. 1145-1149 ◽  
Author(s):  
Richard E. Thorne
Keyword(s):  
Key Words ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Target Strength ◽  
Spawning Ground ◽  
Resident Fish ◽  
Lake Washington ◽  
Visual Observations

Hydroacoustic techniques were used on Lake Washington from 1972 to 1975 to estimate the potential escapement of sockeye salmon (Oncorhynchus nerka). Target strength measurements were used to establish a threshold which would separate the larger adult sockeye salmon from smaller resident fish. The acoustic estimates of escapement were very similar to those obtained from visual observations at the Hiram M. Chittenden ship canal locks, observations on the Cedar River, and spawning ground surveys. Key words: hydroacoustic, acoustic, methodology, sockeye salmon, escapement

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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