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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(brown trout), Fish collections located in the upper reaches of the La Plata were
dominated by native fish (mottled sculpin and speckled dace). Non-native fish at these
sites included rainbow trout, fathead minnow, brook trout and brown trout. No roundtail
chubs were collected upstream of the state line during this time period.

Two tributaries of the La Plata River were sampled at three locations during this decade.
Two sample sites at Long Hollow Creek produced numerous individuals of the native
species bluehead sucker and speckled dace, The one sampling event on Cheny Creek
indicated the presence of three native fish: bluehead sucker, mottled sculpin and
speckled dace,

Mancos River. Fish sampling was conducted on nine occasions in the Mancos River
between 1970 and 1979 (Table 5), Collection events on the lower Mancos near the state-
line established the presence of two native fish (flannclmouth sucker and speckled dace),
and three non-native fish (common carp, red shiner and channel catfish). Site locations
further upstream, above the bridge at Highway 666, produced the same native fish
species as the lower sites with the addition of the bluehead sucker and round tail chub.
Non-native fish species in this reach consisted of the red shiner, channel catfish, and
fathead minnow. At the site locations furthest upstream (near highway 160), fish
collections produced blue head sucker, mottled sculpin, speckled dace and one
flannel mouth sucker. Non-native fish reported from the upper reach of the Mancos River
included the rainbow trout and fathead minnow,

Navajo Wash, a tributary to the Mancos, was also sampled on four occasions from 1970
to 1979. Bluehead sucker, flannelmouth sucker, speckled dace and roundtail chub were
common in collections during this time, Non-native fish that were collected included the
common carp, red shiner, channel catfish, and rainbow trout.

Mc Elmo Creek. Fish sampling was conducted on ten occasions at Mc Elmo Creek
between 1970 and 1979, Upstream locations on Mc Elmo Creek appeared to have lower
numbers of fish than sites located near the San Juan River confluence, Native fish that
most consistently occurred in samples from Mc Elmo Creek included flannelmouth
sucker and speckled dace, Three non-native fish (common carp, red shiner, and fathead
minnow) were also common in fish collections (Table 6), Two native fish (bluehead
sucker and mottled sculpin) additionally occurred in fish collections but not with
regularity,

Draft Final Tributary Report
Miller Ecological Consultants, Inc.

,Ianuary 31, 2000
Page 9