WSP07867

• File Number: 8240.300.31.J
• Description: San Juan River - Environmental Studies
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 2/1/2000
• Title: Ichthyofaunal Surveys of Tributaries of the San Juan River - NM
• Water Supply Pro - Doc Type: Report/Study

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Fish Sampling 1980.. 1989

During the decade 1980-1989 sampling events continued on tributaries to the San Juan
River. Rivers that were sampled included the Animas, Florida, La Plata, and Piedra.
Smaller streams that were sampled included Me Elmo Creek, Navajo Wash, and Rock
Creek (a tributary to the Los Pinos River), The San Juan River upstream of Navajo
Reservoir was also sampled. Data from several sampling events during this decade was
either unavailable or not recorded, Those sampling occasions will be excluded from the
following discussion.

San Juan Tributaries Downstream of Navajo Reservoir

Animas River. The Animas River was sampled four times in reach I and fifteen times in
reach 2 between 1980 and 1989, Native fish collected in reach I included bluehead
sucker, tlannelmouth sucker, mottled sculpin, speckled dace and roundtail chub. Non.
native fish collected in reach I included white sucker, common carp, red shiner,
mosquitofish. fathead minnow, rainbow trout and brown trout. Native fish in reach 2
consisted of bluehead sucker, tlannelmouth sucker, mottled sculpin, and speckled dace,
Non-native fish included the white sucker, common carp, cutthroat trout, rainbow trout,
and brown trout.

During the 1980s there were some noticeable changes in the presence and absence of fish
species in the Animas River. Black bullhead and plains killifish had been collected on
several occasions during the I 970s, but did not occur in any collections during the 1980s.
Red shiner were recorded for the first time since 1954, and white suckers were present in
over 30% of the fish collections from the Animas River. Only one roundtail chub was
collected between 1980 and 1989, It was collected within a 2.5 mile section of reach I
located between Bondad bridge and Cogburn. This was the first occasion on which a
roundtail chub had been collected in the Animas River since 15 Nov, 1963,

Florida River. The Florida River was sampled on nine occasions between 1980 and
1989. Native fish present in collections were similar to those collected during the 1970s
with the addition of two species (tlannelmouth sucker and roundtail chub), Two non-
native fish (fathead minnow and white sucker) that had not previously been collected in
the Florida River were also present in fish collections.

La Plata River, The La Plata River was only sampled two times during the 1980s, Both
sampling occasions occurred during 1988 in the upper reaches (reach 3 and 4) of the
river. Fish species present in collections were similar to those collected in upper reaches
of the La Plata during the 1970s. Native fish collected included tlannelmouth sucker,
mottled sculpin, and speckled dace, Non.native species included fathead minnow,
rainbow trout, brook trout, and brown trout.

Mancos River, The Mancos River and one tributary (Navajo Wash) were sampled a
total often times between 1980 and 1989. The presence, absence, and distribution of

Draft Final Tributary Report
Miller Ecological ConsuUants, Inc.

January 31, 2000
Page 15