Main stem and off-channel habitat use by juvenile Chinook salmon in a sub-Arctic riverscape

Freshwater Biology
By:  and 

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Abstract

  1. Poor growth and survival in freshwater and marine environments have been implicated as responsible for Chinook salmon (Oncorhynchus tshawytscha) declines across Alaska.
  2. Lateral connectivity of river main stems with off-channel habitats may play an integral role in sustaining Alaskan salmonid populations because off-channel habitats commonly provide greater growth opportunities than main stem habitats through greater macroinvertebrate productivity and warmer water temperatures. However, off-channel habitats may impose greater mortality risks to juvenile salmonids, as these habitats are typically more susceptible to drying and are often occupied by potential predators.
  3. We used a hierarchical Bayesian count model to describe juvenile Chinook salmon distributions throughout the Chena River, Alaska in main stem and off-channel habitats and employed diet, prey availability, and bioenergetic analyses to explain these habitat selection decisions from data collected in the summer of 2015.
  4. We found salmon to be most abundant in off-channel habitats as summer temperature increased, which suggested that salmon dispersed to off-channel habitats to take advantage of energetically favourable growth conditions as indicated by the higher prey biomass in benthic and diet samples collected within off-channel habitats.
  5. Our results could have significant implications for juvenile salmon under a warming Alaskan climate as access to productive off-channel habitats may be important to offset increased energetic costs as temperature warms.

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Publication type Article
Publication Subtype Journal Article
Title Main stem and off-channel habitat use by juvenile Chinook salmon in a sub-Arctic riverscape
Series title Freshwater Biology
DOI 10.1111/fwb.13232
Volume 64
Issue 3
Year Published 2019
Language English
Publisher Wiley
Contributing office(s) Coop Res Unit Seattle
Description 4 p.
First page 433
Last page 446
Country United States
State Alaska
Other Geospatial Chena River
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