9528 ‎(2)‎

• UCREFRP Catalog Number: 9528
• Author: Martinez, P. and N. P. Nibbelink.
• Title: Colorado Nonnative Fish Stocking Regulation Evaluation.
• USFW Year: 2004.
• USFW - Doc Type: Grand Junction, Laramie.
• Copyright Material: NO

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Clusters of high green sunfish densities appear to exist throughout the Colorado River
within the ISA, not just near ponds that also have high green sunfish densities.
23. Backwaters sampled as part of three intensive nonnative fish sampling or removal efforts
in the Grand Valley reach of the Colorado River from 1997 to 2001: the Interagency
Standardized Monitoring sampling protocol in, 1997-1998 (Bundy and Bestgen); a
cyprinid removal effort by seining in 1999-2001 (Trammell et al. 2002); and a
centrarchid removal effort by electrofishing in 1999-2001 (Osmundson 2003).
24. Densities of selected nonnative fish sampled in riverine backwaters',from 1997-2001, and
also shown for combined years, 1997-1998 and 1999-2001: a) largemouth bass; b) green
sunfish; c) fathead minnow; d) bluegill; and e) black crappie.
25. Proportion of native and nonnative fish species in riverine backwaters of the Grand
Valley reach of the Colorado River between 1997 and 2001.
26. Proximity analysis relating high density backwater sites for largemouth bass to ponds that
' also had high densities of largemouth bass. There is no difference between high density
and random low or absent backwater locations vs. pond sites. This analysis used
backwater sampling data from Trammell et al. (2002). The error bars represent one
' standard error.
27. Proximity analysis relating hi mouth bass.c'I'hererislno difference between high densi yat
also had high densities of larg
and random low or absent backwater locations vs. pond sites. This analysis used
backwater sampling data from Trammell et al. (2002). The error bars represent one
' standard error.
28. Scattergram results for green sunfish. There is no relationship between density in ponds
' and density in riverine sites at any of the distances indicated.
29. Cross-correlogram results for green sunfish. There is no discernable pattern of
correlation between density in riverine sites and ponds based on distance between
locations.
' 30. Correlogram results for green sunfish in riverine backwater locations. The correlogram
indicates that there maybe slight positive correlations between sites that are very close
' together and sites that are about 12,000 m apart.
31. Semivariogram results for green sunfish. The semivariogram confirms that sites are more
similar when they are closer together and the range of correlation (after which density is
independent of distance) is almost 10,000 m.
32. High density locations for green sunfish are 10-12 km apart, just greater than the "range"
' of spatial correlation indicated by the semivariogram model.
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