Survival Estimates for the Passage of Juvenile Chinook Salmon through Snake River Dams and Reservoirs, 1993 Annual Report.

1994 ◽  
Author(s):  
Robert N. Iwamoto ◽  
Benjamin P. Sandford ◽  
Kenneth W. McIntyre
Keyword(s):  
Chinook Salmon ◽  
Annual Report ◽  
Snake River ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

Fine-scale taxonomic and temporal variability in the energy density of invertebrate prey of juvenile Chinook salmon Oncorhynchus tshawytscha

2020 ◽  
Vol 655 ◽  
pp. 185-198
Author(s):  
J Weil ◽  
WDP Duguid ◽  
F Juanes
Keyword(s):  
Energy Density ◽  
Chinook Salmon ◽  
Temporal Variability ◽  
Energy Content ◽  
Single Point ◽  
Single Species ◽  
Fine Scale ◽  
Temporal Differences ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

Variation in the energy content of prey can drive the diet choice, growth and ultimate survival of consumers. In Pacific salmon species, obtaining sufficient energy for rapid growth during early marine residence is hypothesized to reduce the risk of size-selective mortality. In order to determine the energetic benefit of feeding choices for individuals, accurate estimates of energy density (ED) across prey groups are required. Frequently, a single species is assumed to be representative of a larger taxonomic group or related species. Further, single-point estimates are often assumed to be representative of a group across seasons, despite temporal variability. To test the validity of these practices, we sampled zooplankton prey of juvenile Chinook salmon to investigate fine-scale taxonomic and temporal differences in ED. Using a recently developed model to estimate the ED of organisms using percent ash-free dry weight, we compared energy content of several groups that are typically grouped together in growth studies. Decapod megalopae were more energy rich than zoeae and showed family-level variability in ED. Amphipods showed significant species-level variability in ED. Temporal differences were observed, but patterns were not consistent among groups. Bioenergetic model simulations showed that growth rate of juvenile Chinook salmon was almost identical when prey ED values were calculated on a fine scale or on a taxon-averaged coarse scale. However, single-species representative calculations of prey ED yielded highly variable output in growth depending on the representative species used. These results suggest that the latter approach may yield significantly biased results.

scholarly journals Empirically Estimating Carrying Capacity for Juvenile Chinook Salmon

2021 ◽  
Vol 102 (2) ◽  
Author(s):  
Kevin E. See ◽  
Michael W. Ackerman ◽  
Richard A. Carmichael ◽  
Sarah L. Hoffmann ◽  
Chris Beasley
Keyword(s):  
Chinook Salmon ◽  
Carrying Capacity ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook
Sign in / Sign up

Export Citation Format

Share Document