Skip to page content
USDA Forest Service
  
Treesearch

Research & Development Treesearch

 
Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Northern
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern Research Station
Help
 

Science.gov - We Participate


USA.gov  Government Made Easy


Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.
20090-6090

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

View PDF (0 bytes)

Title: Seasonal and among-stream variation in predator encounter rates for fish prey

Author: Harvey, Bret C.; Nakamoto, Rodney J.;

Date: 2013

Source: Transactions of the American Fisheries Society 142(3): 621-627

Publication Series: Scientific Journal (JRNL)

Description: Recognition that predators have indirect effects on prey populations that may exceed their direct consumptive effects highlights the need for a better understanding of spatiotemporal variation in predator–prey interactions. We used photographic monitoring of tethered Rainbow Trout Oncorhynchus mykiss and Cutthroat Trout O. clarkii to quantify predator encounter rates for fish in four streams of northwestern California during winter–spring and summer. To estimate maximum encounter rates, provide the clearest contrast among streams and seasons, and provide an empirical estimate of a key parameter in an individual-basedmodel of stream salmonids, we consistently placed fish in shallowmicrohabitats that lacked cover. Over 14-d periods, predators captured fish at 66 of the 88 locations where fish were placed. Eight species of birds (including two species of owls) and mammals were documented as capturing fish. Thirty-six percent of the predator encounters occurred at night. Predator encounter rates varied among streams and between seasons; the best-fitting model of survival included a stream × season interaction. Encounter rates tended to be higher in larger streams than in smaller streams and higher in winter– spring than in summer. Conversion of predator encounter rates from this study to estimates of predation risk by using published information on capture success yielded values similar to an independent estimate of predation risk obtained from calibration of an individual-based model of the trout population in one of the study streams. The multiple mechanisms linking predation risk to population dynamics argue for additional effort to identify patterns of spatiotemporal variation in predation risk.

Keywords: stream, fish, predation risk, seasonality

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

XML: View XML

Citation:


Harvey, Bret C.; Nakamoto, Rodney J. 2013. Seasonal and among-stream variation in predator encounter rates for fish prey. Transactions of the American Fisheries Society 142(3): 621-627.

 


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.