scholarly journals Continental-scale variability in the feeding ecology of juvenile Chinook salmon along the coastal Northeast Pacific Ocean

2015 ◽  
Vol 537 ◽  
pp. 247-263 ◽  
Author(s):  
E Hertz ◽  
M Trudel ◽  
RD Brodeur ◽  
EA Daly ◽  
L Eisner ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Feeding Ecology ◽  
Chinook Salmon ◽  
Juvenile Chinook Salmon ◽  
Continental Scale ◽  
Northeast Pacific ◽  
Juvenile Chinook ◽  
Northeast Pacific Ocean

scholarly journals Demographic changes in Chinook salmon across the Northeast Pacific Ocean

2018 ◽  
Vol 19 (3) ◽  
pp. 533-546 ◽  
Author(s):  
Jan Ohlberger ◽  
Eric J Ward ◽  
Daniel E Schindler ◽  
Bert Lewis
Keyword(s):  
Pacific Ocean ◽  
Chinook Salmon ◽  
Demographic Changes ◽  
Northeast Pacific ◽  
Northeast Pacific Ocean

scholarly journals Influences of ocean conditions and feeding ecology on the survival of juvenile Chinook Salmon ( Oncorhynchus tshawytscha )

2016 ◽  
Vol 25 (4) ◽  
pp. 407-419 ◽  
Author(s):  
E. Hertz ◽  
M. Trudel ◽  
S. Tucker ◽  
T.D. Beacham ◽  
C. Parken ◽  
...  
Keyword(s):  
Feeding Ecology ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook ◽  
Ocean Conditions

A century of Chinook salmon consumption by marine mammal predators in the Northeast Pacific Ocean

2016 ◽  
Vol 34 ◽  
pp. 44-51 ◽  
Author(s):  
Jesse Adams ◽  
Isaac C. Kaplan ◽  
Brandon Chasco ◽  
Kristin N. Marshall ◽  
Alejandro Acevedo-Gutiérrez ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Chinook Salmon ◽  
Marine Mammal ◽  
Northeast Pacific ◽  
Northeast Pacific Ocean

scholarly journals Overwinter shifts in the feeding ecology of juvenile Chinook salmon

2016 ◽  
Vol 74 (1) ◽  
pp. 226-233 ◽  
Author(s):  
Eric Hertz ◽  
Marc Trudel ◽  
Strahan Tucker ◽  
Terry D. Beacham ◽  
Asit Mazumder
Keyword(s):  
Feeding Ecology ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Isotope Analysis ◽  
Stomach Contents ◽  
Fish Prey ◽  
Juvenile Chinook Salmon ◽  
Winter Diet ◽  
Juvenile Chinook ◽  
Autumn And Winter

Winter is thought to be a critical period for many fish in the ocean, but their ecology during this time tends to be poorly understood. We quantified the feeding ecology of juvenile Chinook salmon (Oncorhynchus tshawytscha) off the west coast of Vancouver Island in British Columbia, Canada, in autumn and winter to determine how seasonality could affect diet. Using stomach contents and stable isotopes, we tested the hypothesis that the winter diet of juvenile Chinook salmon differs from that of the autumn diet. Stomach-content data showed a shift from a primary reliance on amphipods in autumn to euphausiids in winter. This finding was generally corroborated by the stable isotope analysis, although mixing models suggested a greater contribution of fish prey to the diet in both autumn and winter. Understanding the diet of fish during winter may provide useful information for management as a first step in understanding the factors influencing mortality across life stages.

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.

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