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Asian Copepods on the Move: Recent Invasions in the Columbia–Snake River System, USA
ICES Journal of Marine Science (2008)
  • Jeffrey R. Cordell
  • Stephen M. Bollens
  • Robyn Draheim
  • Mark D. Sytsma, Portland State University

Nine Asian copepod species have been introduced into the Northeast Pacific, seven of which are largely confined to the San Francisco estuary. However, several of these copepods recently invaded the Columbia–Snake River system in Washington state, USA. In addition to the calanoid copepod Pseudodiaptomus inopinus, which appeared in the 1980s, the Columbia River now has populations of the calanoids Pseudodiaptomus forbesi and Sinocalanus doerrii, and the cyclopoid copepod Limnoithona tetraspina. Sampling in the Columbia–Snake River system in 2005 and 2006 indicated that (i) newer invaders may have displaced the previously introduced P. inopinus; (ii) P. forbesi had moved upstream into the first five reservoirs in the system; (iii) the other species occurred only in the tidal regions of the lower river; (iv) P. forbesi dominates the late summer holoplankton in the lower river and estuary; and (v) P. forbesi is relatively rare, and the holoplankton is dominated by native species in upstream free-flowing segments of the Columbia River and in reservoirs of the Snake River. Zooplankton samples from ships in Puget Sound suggest that ballast water from California is a major source of the introduced copepods and that the Columbia River itself may be a new source of ballast-introduced copepods

  • Aquatic ecology -- Research -- United States,
  • Invasive species,
  • Columbia River Basin -- Environmental conditions
Publication Date
Publisher Statement
Copyright (2008) Oxford University Press
Citation Information
Jeffrey R. Cordell, Stephen M. Bollens, Robyn Draheim and Mark D. Sytsma. "Asian Copepods on the Move: Recent Invasions in the Columbia–Snake River System, USA" ICES Journal of Marine Science Vol. 658 Iss. 5 (2008)
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