Somatic energy of sockeye salmon Oncorhynchus nerka at the onset of upriver migration: a comparison among ocean climate regimes

2004 ◽  
Vol 13 (5) ◽  
pp. 345-349 ◽  
Author(s):  
Glenn T. Crossin ◽  
Scott G. Hinch ◽  
Anthony P. Farrell ◽  
David A. Higgs ◽  
Michael C. Healey
2006 ◽  
Vol 63 (7) ◽  
pp. 1469-1480 ◽  
Author(s):  
Steven J Cooke ◽  
Scott G Hinch ◽  
Glenn T Crossin ◽  
David A Patterson ◽  
Karl K English ◽  
...  

Beginning in 1995, segments of the late-run sockeye salmon (Oncorhynchus nerka) stocks from the Fraser River, British Columbia, have initiated upriver spawning migration up to 6 weeks earlier than historical records; and those fish have experienced high rates of en route mortality. We examined the correlations between physiological and energetic status prior to river entry with subsequent migratory performance of individual salmon using telemetry and noninvasive biopsies for Adams–Thompson–Shuswap (Adams) and Weaver–Harrison (W–H) stocks. Salmon that failed to reach the river were characterized by a tendency to have elevated levels of chronic and acute stress indicators. For one stock of fish (i.e., Adams) that entered the river, those that died before reaching spawning grounds were individuals with low gross somatic energy. Furthermore, females tended to have elevated plasma estradiol levels. When contrasting fish with different behaviours and fates, fish that did not hold in the estuary and subsequently died tended to have less energy than fish that held and reached spawning areas. Females from the former group also had higher 11-ketotestosterone and estradiol levels relative to those from the later group. These data suggest that differences in physiological and energetic status may be associated with high en route mortality in late-run sockeye salmon.


2006 ◽  
Vol 63 (5) ◽  
pp. 1067-1077 ◽  
Author(s):  
Jeffery L Young ◽  
Scott G Hinch ◽  
Steven J Cooke ◽  
Glenn T Crossin ◽  
David A Patterson ◽  
...  

Since 1995, large segments of the late-run sockeye salmon (Oncorhynchus nerka) stock complex from the Fraser River, British Columbia, Canada, have been initiating spawning migrations several weeks earlier than normal. Most aberrant migrants die before spawning. To evaluate the mechanisms underlying the mortality, we intercepted late-run sockeye salmon of the Adams–Shuswap stock complex halfway along their freshwater migration (i.e., in the Thompson River Canyon situated 270 km from the Fraser estuary), nonlethally assessed physiological and energetic status, and tracked individuals using gastrically inserted radio transmitters. Aberrant migrants that resumed their migration but failed to reach the spawning grounds had lower gross somatic energy, higher average migration ground speeds, higher plasma osmolality, and higher levels of plasma reproductive hormones than those that reached the spawning grounds. Fish surgically fitted with electromyogram radio transmitters did not continue their migration and fell downstream. These fish displayed excessive bleeding during transmitter implantation, an unusual phenomenon that likely contributed to the fish's inability to resume migration. Blood clotting time decreased steadily throughout the migration period. Collectively, these data implicate a combination of energy depletion, premature reproductive development, and blood loss from wounds as potential contributors to mortality in early migrating late-run sockeye.


Author(s):  
Thomas P. Quinn ◽  
George R. Pess ◽  
Ben J.G. Sutherland ◽  
Samuel J. Brenkman ◽  
Ruth E. Withler ◽  
...  

1987 ◽  
Vol 44 (9) ◽  
pp. 1551-1561 ◽  
Author(s):  
Jeremy S. Collie ◽  
Carl J. Walters

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.


2017 ◽  
Vol 91 (1) ◽  
pp. 41-57 ◽  
Author(s):  
S. C. Godwin ◽  
L. M. Dill ◽  
M. Krkošek ◽  
M. H. H. Price ◽  
J. D. Reynolds

2015 ◽  
Vol 87 (1) ◽  
pp. 169-178 ◽  
Author(s):  
C. Freshwater ◽  
M. Trudel ◽  
T. D. Beacham ◽  
C.-E. Neville ◽  
S. Tucker ◽  
...  

1960 ◽  
Vol 17 (3) ◽  
pp. 347-351 ◽  
Author(s):  
J. D. Wood ◽  
D. W. Duncan ◽  
M. Jackson

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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