EPSCoR - Alaska Adapting to Changing Environments

EPSCoR - Alaska Adapting to Changing Environments

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Mechanisms of drift-feeding behavior in juvenile Chinook salmon and the role of inedible debris in a clear-water Alaskan stream

Drift-feeding fish are challenged to discriminate between prey and similar-sized particles of debris, which are ubiquitous even in clear-water streams. Spending time and energy pursuing debris mistaken as prey could affect fish growth and the fitness potential of different foraging strategies. Our goal was to determine the extent to which debris influences drift-feeding fish in clear water under low-flow conditions when the distracting effect of debris should be at a minimum. We used high-definition video to measure the reactions of drift-feeding juvenile Chinook salmon (Oncorhynchus tshawytscha) to natural debris and prey in situ in the Chena River, Alaska. Among all potential food items fish pursued, 52 % were captured and quickly expelled from the mouth, 39 % were visually inspected but not captured, and only 9 % were ingested. Foraging attempt rate was only moderately correlated with ingestion rate (Kendall’s τ = 0.55), raising concerns about the common use of foraging attempts as a presumed index of foraging success. The total time fish spent handling debris increased linearly with foraging attempt rate and ranged between 4 and 25 % of total foraging time among observed groups. Our results help motivate a revised theoretical view of drift feeding that emphasizes prey detection and discrimination, incorporating ideas from signal detection theory and the study of visual attention in cognitive ecology. We discuss how these ideas could lead to better explanations and predictions of the spatial behavior, prey selection, and energy intake of drift-feeding fish.

Data and Resources

  • View website
    Website :: Publisher's website

    http://link.springer.com/article/10.1007/s10641-014-0227-x/fulltext.html

Status: Complete
Type: Project
Data Types: Report
Primary Contact
Wipfli, Mark
Professor of Freshwater Ecology, UAF
Email: mwipfli@alaska.edu
Work: (907) 786-1637
Primary Agency
EPSCoR - Alaska Adapting to Changing Environments
Type
Academic

Funding Agency
EPSCoR - Alaska Adapting to Changing Environments
Type
Academic

Other Agencies
National Science Foundation

ISO Topics
health, inlandWaters

Geo-keywords
Alaska

Direct Record Link
http://northern.epscor.alaska.edu/catalogs/11759-mechanisms-of-drift-feeding-behavior-in-juvenil
  • 01c8ceef3d596f40f05bf496ca00d929
    Updated by Lisa
    2016-09-28 16:06:40 -0800
  • 01c8ceef3d596f40f05bf496ca00d929
    Updated by Lisa
    2016-09-28 16:06:26 -0800
  • 01c8ceef3d596f40f05bf496ca00d929
    Published by Lisa
    2016-09-28 16:04:47 -0800
  • 01c8ceef3d596f40f05bf496ca00d929
    Updated by Lisa
    2016-09-28 16:04:28 -0800
  • 54f31cdd126d223f25ff87f2305bf214
    Updated by Roberta
    2016-09-27 15:38:22 -0800
  • 54f31cdd126d223f25ff87f2305bf214
    New record created
    2016-09-27 15:19:04 -0800
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