WSP02775

• File Number: 8220.106
• Description: Animas-La Plata
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 10/25/1991
• Title: Final Biological Opinion - 1991
• Water Supply Pro - Doc Type: Biological Opinion

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3. Highest documented reproduction for Colorado sQuawfish occurred in 1987
concurrently with high spring flows,

4. Suitable Colorado sQuawfish spawning habitat appeared to be present
throughout occupied reaches of the San Juan River.

5. Young-of-year sQuawfish were collected from three main areas: in the
vicinity of the Mancos River confluence in New Mexico; in the vicinity of
the Montezuma Creek confluence near Bluff, Utah; and the upstream portion
of the San Juan River inflow to Lake Powell.

6. Upstream migrational movement of Colorado sQuawfish was documented in
1987. A Colorado sQuawfish captured and tagged in April 1987 in the upper
terminus of the San Juan Arm in Lake Powell was recaptured approximately
90 river miles upstream in the San Juan River in September. No other
tagged Colorado sQuawfish were recaptured during this 3-year study.

7. Colorado sQuawfish were captured in all seasons during ichthyofaunal
surveys (spring, summer, and fall) and are believed to inhabit the San
Juan River year round.

Within the San Juan River subbasin, the San Juan River supports a small
population of reproducing Colorado sQuawfish; however, the extent of annual
recruitment and/or survival of young fish has not been determined. Recent field
studies (Platania 1990) document a greater number of Colorado sQuawfish (adults
and young-of-year) in the San Juan River than was previously known to occur.
The San Juan River is one of only three remaining areas where a wild,
reproducing population of Colorado sQuawfish still persists. As the
southernmost tributary in the Upper Basin, the San Juan River peaks earlier in
the year, attaining warmer water temperatures than other Upper Basin streams and
promoting longer and better growth potential for young Colorado sQuawfish,

Any additional losses or further degradation of remaining San Juan River
habitats, resulting in further reductions in distribution and abundance of
Colorado sQuawfish, will exacerbate problems the species is currently
experiencing in the San Juan River and throughout the remainder of the Upper
Basin. Protection and enhancement of the San Juan River is needed to provide
additional protection against possible extinction of the Colorado sQuawfish
while reducing total dependency on the Colorado and Green Rivers systems for
survival and recovery. The San Juan River subbasin, isolated from the Colorado
and Green Rivers subbasins, provides a third population of wild fish,
contributing an additional essential buffer against a catastrophic event (such
as an oil spill) elsewhere in the basin,

Furthermore, the Colorado River Fishes Recovery Team (consisting of scientists
from the entire Colorado River Basin, including representatives from State
wildlife agencies of California, Arizona, New Mexico, Utah, and Colorado, as
well as Federal representatives from the National Park Service, Reclamation, and
the Service) recommended to the Service in September of 1985 that n. . . the San