8173

• UCREFRP Catalog Number: 8173
• Author: Gido, K. B. and D. L. Propst.
• Title: Habitat Use and Association of Native and Nonnative Fish in the San Juan River, New Mexico and Utah.
• USFW Year: n.d.
• USFW - Doc Type: \
• Copyright Material: NO

large number of significant positive associations between
juvenile R. osculus and nonnatives, the magnitude was small and
significance was probably a consequence of large sample size.
Significant negative association occurred between R. osculus and

adult ~. lutrensis, and ~. discobolus and E. zebrinus.

Adult and sub-adult native species showed the lowest degree

of habitat overlap with nonnative species (Fig. 7). Among these, F

sub-adult ~. latipinnis had the greatest number of significant

positive associations with nonnative species. Adult R. osculus

had a significant positive association with adult ~. lutrensis

while it had a significant negative association with juvenile ~.

promelas and ~. affinis.

Ictalurus punctatus, E. zebrinus, and A. melas showed

negligible association with native fish species. Sub-adult~.

discobolus had no significant association with any other

nonnative species and the observed overlap was greater than

expected for only two of the eleven comparisons.

When sample size was sufficiently large, we also assessed

the habitat associations between native and nonnative species

using Spearman's rank correlation (Table 6). Significant '-Co

positive correlations in abundance of larval natives and

nonnatives only occurred between larval ~. discobolus and

juvenile ~. promelas, ~. lutrensis, and~. carpio. Abundance of

larval ko latipinnis showed a significant negative correlation

with juvenile ~. promelas and larval ~o lutrensis. Thus, even

though there was a significant positive association among these

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