Do Rainbow Trout and their Hybrids Outcompete Cutthroat Trout in a Lentic Ecosystem

Abstract

Much has been written about introduced rainbow trout interbreeding and outcompeting native cutthroat trout. However, the specific mechanisms by which rainbow trout and their hybrids outcompete cutthroat trout have not been thoroughly explored, and most of the published data is limited to lotic ecosystems. Materials and Methods: Samples of Snake River cutthroat trout (Oncorhynchus clarkii bouvieri), the rainbow-cutthroat hybrid, the cutbow trout (Onchorhynchus mykiss x clarkii), and rainbow trout (Oncorhynchus mykiss), were obtained from a lentic ecosystem (Eleven Mile Reservoir, Colorado) by creel surveys conducted from May to October, 2012. The total length and weight of each fish was measured and the relative condition factor of each fish was computed using expected weight from weight-length relationships from the Colorado Division of Parks and Wildlife (CDPW). Data from the CDPW collected from 2003 - 2010 in the same lentic ecosystem were used to compute relative condition factors for additional comparison, as was independent creel survey data from 2011. The data was also compared with minimum, 25th percentile, mean, 75th percentile, and maximum weight-length curves generated from data in Carlander's Handbook of Freshwater Fisheries Biology (1969). Results: Cutthroat trout were plump: the mean relative condition factor of the cutthroat trout was 112.0% (+or- 1.0%). Cutbow hybrid trout were close to the expected weights with a mean relative condition factor of 99.8% (+or- 0.6%). Rainbow trout were thinner with a mean relative condition factor of 96.4% (+or- 1 .4%). In May, 2012, all three taxa measured had average relative condition factors greater than 100%, which generally declined over the study period.

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Document Details

Document Type
Technical Report
Publication Date
Jan 25, 2013
Accession Number
AD1015620

Entities

People

  • Amy C. Courtney
  • Joshua M. Courtney
  • Michael W. Courtney

Organizations

  • United States Air Force Academy

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Air Force
  • British Columbia
  • Colorado
  • Department Of Defense
  • Fish
  • Fisheries
  • Geographic Regions
  • North America
  • United States
  • Wildlife

Fields of Study

  • Environmental science

Readers

  • Aerial Delivery - Logistics and Supply Chain Management.
  • Regression Analysis.
  • Riverine Ecology