9433

• UCREFRP Catalog Number: 9433
• Author: Anderson, R.
• Title: Riverine Fish Flow Investigations.
• USFW Year: 2002.
• USFW - Doc Type: Federal Aid Project F-288-R5,
• Copyright Material: NO

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RESULTS AND DISCUSSION

YAMPA RIVER FISH SAMPLES

Species Composition - fish over 15 cm

Native species composition for fish over 15 cm was found to be distinctive for the three
stations (Lily Park, Sevens and Duffy) in 2001 as was also found in 2000 (Anderson and Stewart
2001). Lily Park had by far the largest sample size, with 2,990 fish (Table 4). Flannelmouth
sucker was the most common species at Lily Park (68%) and Sevens (53%), but was rare at
Duffy with 2% of the fish (Table 2). Bluehead sucker composition was 7%, 13%, and 4% at
Lily Park, Sevens and Duffy, respectively. Roundtail chub were very rare at Lily Park with only
1 fish collected or 0.03% of the catch. Roundtail chub comprised 3% at both Sevens and Duffy
(Table 4). Colorado pikeminnow were rare to absence at all sites in 2001 with .03% at Lily Park,
zero at Sevens and 0.6% at Duffy.

Also, nonnative species composition for fish over 15 cm was distinctive between stations
in 2001. The second most common species at Lily Park was channel catfish, and was 18%.
Channel catfish comprised 5% at Sevens and 4% at Duffy (Table 4). At Duffy, the most
common fish taxa is the white sucker complex, which includes white-flannel mouth and white-
bluehead crosses. White sucker and crosses were 50% at Duffy, 16% at Sevens and only 0.2% at
Lily Park in 2001. The second most common species at Duffy was small mouth bass with a
composition of 32%, but small mouth composition was 5% at both Sevens and Lily Park (Table
4). Carp were uncommon at all sites and at 2%, 4% and 2% at Lily Park, Sevens and Duffy,
respectively. Northern pike have become rare at all sites and in 2001 were at 0.2%, 0.3% and
1 % and Lily Park, Sevens and Duffy, respectively.

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