DIRECTIONAL SELECTION BY FISHERIES AND THE TIMING OF SOCKEYE SALMON (ONCORHYNCHUS NERKA) MIGRATIONS

2007 ◽  
Vol 17 (3) ◽  
pp. 731-739 ◽  
Author(s):  
Thomas P. Quinn ◽  
Sayre Hodgson ◽  
Lucy Flynn ◽  
Ray Hilborn ◽  
Donald E. Rogers
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Directional Selection

Effects of population-specific variation in age and length on fishery selection and exploitation rates of sockeye salmon (Oncorhynchus nerka)

2009 ◽  
Vol 66 (6) ◽  
pp. 896-908 ◽  
Author(s):  
Neala W. Kendall ◽  
Thomas P. Quinn
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Age Groups ◽  
River System ◽  
Directional Selection ◽  
Size At Maturity ◽  
Natural Processes ◽  
Fishery Exploitation ◽  
Specific Variation ◽  
Complex Variation

Conspecific salmonid populations often differ in age and body size at maturity, and these differences can cause fishery exploitation rates and patterns of directional selection on size to vary among populations. Based on age and length data on five representative spawning populations of sockeye salmon ( Oncorhynchus nerka ) in the Wood River system, Bristol Bay, Alaska, USA, we estimated exploitation rates and population-specific patterns of selection from a gillnet fishery between 1963 and 2007. Exploitation rates have differed among age groups and have varied greatly over time, likely due to changes in fishery selectivity. Populations with older, larger fish were more heavily exploited than populations with small, young fish. Differential fishery selection was detected among the populations, linked to persistent differences in size and age of fish among the populations. Specifically, we found evidence of stronger size selectivity on populations with smaller-bodied fish and less directional selection on populations dominated by larger-bodied fish. These results reveal the complex variation in the intensity and selectivity of fishing that can result from exploitation of populations that differ in age and size at maturity and shape. Evolutionary responses to this selection may be taking place, but natural processes provide countervailing selection.

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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