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

.I
'>
')
" r)
I c')
" :-~
.. ,)
J 0
) "-~
)
"
1
i
,
..)
-1
..)
;
"
,
"
",

",;'

,.i

"
.~

Ameiurus me/as (black bullhead): Early records of this species in the study area include
several sampling events which occurred during the summer of 1976 on the Animas River.
These were the only reports of black bullheads until the 1990s, Since 1992 small
numbers of black bullheads have been reported from several major tributaries of the San
Juan River. The tributaries from which black bullheads have been reported include; the
Los Pinos River, Navajo River, Florida River and La Plata River. This non-native
species was represented by a few juvenile and adult individuals throughout the] 994
habitat study. CoHections of black bullheads occurred in glide and pool habitat.

Icta!uruspunctalus (channel catfish): The earliest reports ofchanneJ catfish in tributaries
of the San Juan River came from sampling efforts on the Mancos River in 1975;
however, Olson (1962b) reported this species during a pre-impoundment study of the
Navajo Reservoir area, By 1992 this non-native species had also been reported from two
major tributaries (the Los Pinos and Piedra rivers) upstream of Navajo Reservoir. During
the 1994 habitat study this species was represented in the data by only two records. On
both occasions an adult fish was captured in the Mancos River while occupying pool
habitat.

Fundu/us zebrinus (plains killifish): During] 976 this non-native species was collected
from the Animas River and La Plata River. These were the only reported collections of
plains killifish in the study area. It was not collected during the MEC habitat use study.

Gambusia affinis (mosquito fish): Earliest reports of this species in the upper San Juan
drainage came from the Animas ,River during 1961. Since that time it has only been
reported from two other sampling events, Both of these occurred on the Animas River
during the 1989. These are the only historical records of this non-native species in the
San Juan drainage, The mosquito fish was not encountered during the habitat use study.

Lepomis cyanel/us (green sunfish): This non-native species appeared in low numbers
,over a widespread area of the San Juan drainage during the early] 990s. It was collected
in the Florida River during 1991, and the Los Pinos and Animas rivers during 1993,
During 1994 it was also reported from the Navajo River, and Mc Elmo Creek, Only the
juvenile size class of green sunfish was represented in the 1994 habitat use study, These
fish were encountered in all three major habitat types,

Micropterus d%mieu (smallmouth bass): The smaHmouth bass was only represented by
one individual during historical sampling events in the San Juan drainage, This single
specimen was collected from the San Juan River upstream of Navajo Reservoir during
1992. The smallmouth bass was not reported during the] 994 habitat use study.

Draft Final Tributary Report
Miller Ecological Consultants, Inc.

January 3],2000
Page 25