Effects of Starvation, Feeding, and Light Period on Circulus Formation on Scales of Young Sockeye Salmon (Oncorhynchus nerka)

1971 ◽  
Vol 28 (11) ◽  
pp. 1749-1755 ◽  
Author(s):  
H. T. Bilton ◽  
G. L. Robins
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Light Period ◽  
Starvation Period ◽  
Scale Growth ◽  
Ad Libitum

Young sockeye salmon (Oncorhynchus nerka) survived a starvation period of 20 weeks with no change in their mean length and weight and with no record of this starvation period on their scales. Fish offered an ad libitum diet for more than 4 weeks in the 20-week period had significant increases in body and scale growth. The number of checks on their scales was correlated with the number of weeks fish were offered an ad libitum diet and not with the number of weeks they were starved. Thus, a significant increase in food induced the formation of a check. Light period appeared to have some influence on body and scale growth.

Response of Young Sockeye Salmon (Oncorhynchus nerka) to Prolonged Periods of Starvation

1971 ◽  
Vol 28 (11) ◽  
pp. 1757-1761 ◽  
Author(s):  
H. T. Bilton ◽  
G. L. Robins
Keyword(s):  
Recovery Time ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Light Period ◽  
Scale Growth

Young sockeye were held without food for periods of 20 and 30.5 weeks with few mortalities. As was reported in previous experiments, no record of the periods of starvation appeared on the scale, nor did checks form under these conditions. Those fish offered food after 20 weeks of starvation responded immediately and showed significant increases in body and scale growth at the end of 10 weeks feeding. Fish offered food after 30.5 weeks of starvation also responded immediately, but when the experiment ended after 5 weeks of feeding no significant increases in body and scale growth were apparent, indicating insufficient recovery time. A significant increase in the incidence of checks was associated with subsequent feeding. Light period did have some influence on body and scale growth.

The Effects of Starvation and Subsequent Feeding on Survival and Growth of Fulton Channel Sockeye Salmon Fry (Oncorhynchus nerka)

1973 ◽  
Vol 30 (1) ◽  
pp. 1-5 ◽  
Author(s):  
H. T. Bilton ◽  
G. L. Robins
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
River Channel ◽  
Salmon Fry ◽  
Survival And Growth ◽  
Ad Libitum

In the laboratory 8 groups of Fulton River channel fry were starved for periods ranging from 1 to 7 weeks, then offered food ad libitum for 8 weeks. Fry withstood up to 4-weeks starvation with less than 10% mortality; beyond this point mortality increased sharply to 90% at 7-weeks starvation. At 5-weeks starvation both fry length and weight decreased significantly. Mortality continued when fish were offered food ad libitum after being starved. Among fish starved for 1 and 2 weeks, mortalities continued to be low, 0 and 6.6%, respectively; but, among fish starved from 3 to 5 weeks, mortalities rose considerably, ranging from 42 to 99%.

Effects of Feeding Level on Circulus Formation on Scales of Young Sockeye Salmon (Oncorhynchus nerka)

1971 ◽  
Vol 28 (6) ◽  
pp. 861-868 ◽  
Author(s):  
H. T. Bilton ◽  
G. L. Robins
Keyword(s):  
Significant Influence ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Scale Growth ◽  
Feeding Level ◽  
Experimental Populations

Feeding level exerted a significant influence on scale growth of young sockeye salmon (Oncorhynchus nerka) maintained for 2 months at a temperature of 13.98 ± 0.29 C and a constant photoperiod of 12 hr light and dark. The number and spacing of circuli, scale radius, and length and weight of the fish were all correlated with the feeding level. Two checks at most were observed on scales of fish in the experimental populations. At midpoint of the experiment, incidence of a first check was highest among fish that had been held at a high feeding level. At the end of the experiment a second check was apparent only on scales of fish that had the feeding levels raised at midpoint of the experiment. There were significant correlations between the nucleus radius of the scale and length and weight of the fish.

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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