The following is a document archive for the native fish of the Colorado River, which have the highest rate of jeopardy toward extinction in the nation. Read article here.

Historically, the native fish fauna of the Colorado River Basin was dominated by the minnow (cyprinids) and sucker (catostomids) families. Of the 34 known native species to the Colorado River basin, 74% are found nowhere else in the world, or endemic.

Threats to these species include streamflow regulation and habitat modification, altered food web, predation by nonnative fish species, parasitism, hybridization with other native fish species, and pesticides, toxins and pollutants. These changes to the river environment have occurred so quickly that the species have been unable to a adapt, so pro-active human intervention is the only hope they have. Since the river is truncated by 83 dams in the upper basin and 10 dams in the lower basin, this loss of genetic diversity will also impede their recovery.

SEARCH ENGINE of US Fish and Wildlife Service

Click here to view bibliographies of endangered fish research

BIOLOGICAL OPINIONS/MEMOS by US Fish and Wildlife Service unless specified.

Section 7 Consultation Handbook

1978 - Biological Opinion, Glen Canyon Dam

1979 - Biological Opinion, Dallas Park Project

1980 - Biological Opinion, Dolores River Project

1992 - Biological Opinion, Flaming Gorge Dam

1994 - Biological Opinion, Glen Canyon Dam

1995 - Memo in response to 1994 BiOp. Reclamation.

1997 - Instream Flow Recommendations Lower Gunnison. Burdick.

1997 - Biological Opinion, Lower Colorado River

1997 - Biological Opinion, Glen Canyon Dam

1997 - Biological Opinion, Lower Colorado operations

1999 - Biological Opinion of the Upper Colorado

1999 - Flow Recommendations for San Juan River

2000 - Flaming Gorge Dam Flow Recommendations

2001 - Biological Opinion, Surplus Criteria

2002 - Biological Opinion, Glen Canyon Dam

2002 - Biological Opinion, Lower Colorado River

2003 - Biological Opinion, Glen Canyon Dam

2003 - Gunnison and Colorado River Flow Recommendation

2004 - Biological Opinion, Glen Canyon Dam

2004 - Biological Opinion, Moab Uranium Mill

2005 - Biological Opinon, Yampa River

2005 - Biological Opinion, Flaming Gorge Dam

2005 - Biological Opinion, Multiple-Species Conservation Program

2005 - Biological Assessment, Grand Canyon National Park

2006 - Biological Opinion, Navajo Dam

2006 - Experimental Flow Options, Glen Canyon Dam

2007 - Biological Opinion, Shortage Criteria

2008 - Biological Opinion, Glen Canyon Dam

2008 - Biological Assessment, Aspinall Unit (Gunnison River). Reclamation.

2009 - Supplemental Biological Opinion Glen Canyon Dam

2010 - Biological Assessment, Green River Pumping Project. Reclamation.

Sufficient Progress Reports from FWS, Glen Canyon Dam

Sufficient Progress Reports from Reclamation, Glen Canyon Dam

Listing in the Federal Register

(1) Colorado squawfish - March 11, 1967 (32 FR 4001)
(2) humpback chub - March 11, 1967 (32 FR 4001)
(3) bonytail chub - April 23, 1980 (45 FR 27713)
(4) razorback sucker - October 23, 1991 (56 FR 54957)

COLORADO RIVER AND ITS TRIBUTARIES

Upper Colorado River

1998 - Geomorphology and endangered fish habitats of the upper Colorado River. Vanstetter.

1998 - Status and Trends of Colorado Pikeminnow. Osmundson et al.

2006 - Upper Colorado River Endangered Fish Populations. UCR Recovery Program.

2007 - Utah conservation plan for threatened fish species. Utah Division of Wildlife.

Gunnison River

1997 - Instream Flow Recommendations Lower Gunnison. Burdick.

2007 - Analysis of Dissolved Selenium. Thomas, et al.

Dolores River

1992 - Dolores River Native Fish Habitat Study. Valdez, et al.

Green River

2000 - Effects of Tusher Wash Diversion Dam on Native Fish. Utah Division of Wildlife.

2006 - Annual report of operations at Flaming Gorge Dam

2007 - Green River Study Plan

2007 - Annual report of operations at Flaming Gorge Dam

2008 - Annual report of operations at Flaming Gorge Dam

Yampa River

Canyonlands (Southeast Utah Group)

1990 - Endangered Fish of Cataract Canyon. Valdez.

1999 - Driftwood: an alternative habitat for macroinvertebrates in a large desert river. Haden et al.

1999 - Movement patterns, behavior, and habitat use of razorback sucker stocking into the Green River at Canyonlands National Park, Utah. Foster et al.

2000 - Spatiotemporal Variation in Length-Weight Relationships of Endangered Humpback Chub for Conservation and Management. Meretsky et al.

2008 - Population Estimates for Humpback Chub in Cataract Canyon 2003-2005. Badame.

Glen Canyon National Recreation Area (Lake Powell)

San Juan River

1996 - Colorado Pikeminnow Distribution and Movement. Ryden.

1994 - Management of Discharge, Temperature, and Sediment in Grand Canyon for Native Fish. Clarkson et al.

1997 - Habitat Relationships of Subadult Humpback Chub in the Colorado River through Grand Canyon. Converse et al.

2000 - Spatiotemporal Variation in Length-Weight Relationships of Endangered Humpback Chub for Conservation and Management. Meretsky et al.

2002 - Monitoring and Research: The Aquatic Food Base in the COlorado River, Arizona During 1991-2001. Benenati et al.

2004- Evidence for the failure of the modified low fluctuating flow. Korman et al.

2005 - State of the Colorado River in Grand Canyon. US Geological Survey.

2007 - Abundance Trends and Status of the Little Colorado River Population of Humback Chub: An update Considering 1989 - 2006 Data. Coggins.

2009 - List of extirpated species in Grand Canyon

Lower Colorado River

2002 - Lost, a desert river and its native fishes: A historical perspective. Mueller and Marsh. US Geological Survey.

Gulf of California, Delta and Limitrophe

Endangered species
Vaquita Porpoise
Totoaba

LISTING AS ENDANGERED
Federal Register Notices

(1) Colorado squawfish - March 11, 1967 (32 FR 4001)
(2) humpback chub - March 11, 1967 (32 FR 4001)
(3) bonytail chub - April 23, 1980 (45 FR 27713)
(4) razorback sucker - October 23, 1991 (56 FR 54957)

PHOTOS

The endangered fish
(1) Colorado squawfish (Ptychocheilus lucius) (photo)
(2) humpback chub (Gila cypha) (photo) (close-up not public domain)
(3) bonytail chub (Gila elegans) (photo)
(4) razorback sucker (Xyrauchen texanus) (photo)

Photos for detailed identification
Bluehead sucker
Flannelmouth sucker
Colorado Pikeminnow
Razorback sucker
Roundtail chub
Young humpback chub

PRESS

2010 - One tough sucker. High Country News.

RECOVERY GOALS
Colorado pikeminnow
Humpback chub
Bonytail chub
Razorback sucker