BOARD00038 ‎(2)‎

• Board Meeting Date: 9/20/2006
• Description: WSP Section - San Juan River Recovery Implementation Program Document Revisions
• Board Meetings - Doc Type: Memo

.

Table 2. Non-native Fish Fauna of the San Juan River Basin
S ecies Status and Distribution
Threadfin Shad Lake Powell, ma rarel enter riverine habitats
Cutthroat Trout (Snake River
subs ecies
Rainbow Trout
Brown Trout
Kokanee Salmon

Common, generally distributed and typically not numerous

.

Northern Pike

Red Shiner
Common Ca
Golden Shiner
Sand Shiner
Fathead Minnow
White Sucker
Black Bullhead
Channel Catfish
Plains Killifish
Mos uitofish
S tri ed Bass
Green Sunfish
Blue ill
Small mouth Bass
Lar emouth Bass

White Crappie

Black Cra ie

Water Quality

The water quality of the San Juan River is influenced by both natural and anthropogenic factors.
The river exhibits the results of these influences both longitudinally and seasonally as it flows
through the habitat occupied by the endangered fish species. Like much of the Western United
States, the San Juan Basin is considered naturally seleniferous. Data concerning concentrations of
selenium in the mainstem of the San Juan River indicate a general increase in concentration levels
as distance downstream increases from Archuleta, New Mexico (downstream of Navajo Dam) to
Bluff, Utah. While the mean concentration of dissolved selenium is less than 1 Jlg/l, 41% of the
readings are above detection (1 Jlg/l) at Mexican Hat while there are no samples above detection at
Archuleta (1994-2004 monitoring period). The maximum recorded level at Mexican Hat is 4 Jlg/l.
Tributaries to the San Juan River carry higher concentrations of selenium than are found in the
mainstem of the river immediately upstream from their confluence with the San Juan. Although
these levels are diluted by the flow of the San Juan River, the net effect is a gradual increase in
concentration of the element in the river as it travels downstream. Increased selenium

.

5