HR: 14:45h
AN: NB23A-06    [Abstracts]
TI: Ecoregional and State Differences in the Effects of Nonnative Fish on Fish Assemblage Structure
AU: * Lomnicky, G A
EM: lomnicky.gregg@epa.gov
AF: Dynamac Inc., 200 SW 35th St., Corvallis, OR 97333 United States
AU: Hughes, R M
EM: hughes.bob@epa.gov
AF: Oregon State University, 200 SW 35th St., Corvallis, OR 97333 United States
AU: Whittier, T R
EM: whittier.thom@epa.gov
AF: Dynamac Inc., 200 SW 35th St., Corvallis, OR 97333 United States
AU: Peck, D V
EM: peck.david@epa.gov
AF: Western Ecology Division, NHEERL, ORD, US Environmental Protection Agency, 200 SW 35th St., Corvallis, OR 97333 United States
AB: Nonnative aquatic vertebrates have been widely introduced across the western U.S. We analyzed data from 1039 site visits sampled during 2000 -2003 by the U.S. EPA's Environmental Monitoring and Assessment Program's (EMAP) Western Pilot to determine occurrence and proportion of stream length occupied by nonnative fish and aquatic amphibians in streams and rivers of 12 conterminous western states and three ecoregions (Western Forest, Plains, Xeric). An estimated 41% (±5%) of the stream length in the region, where vertebrates were collected, contained nonnative vertebrates. Nonnatives represented greater than 50% of the individuals in 18% of the stream length and were present in over 80% of the length of 5^th order or larger rivers. The Plains contained the greatest number of nonnative species versus other ecoregions. Trout (rainbow, brown, brook) are the most common nonnatives found in the western states. California contained the most nonnative taxa collected (27) while 7 of 12 predominant fish in Arizona are nonnatives. Nonnatives are usually gamefish or fish supporting game fish including baitfish such as minnows.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly