The U.S. Fish and Wildlife Service has designated four different species of fish native to the Colorado River as endangered: Colorado pikeminnow, razorback sucker, bonytail chub, and the humpback chub. These fish were once plentiful in the Colorado and its tributaries. However, their numbers have declined dramatically. Listing provides legal protection from human-caused killing or removal, except in specifically permitted circumstances. This protection typically represents additional regulatory requirements for development of new or operation of existing facilities.
The Colorado pikeminnow is North America's largest minnow. These fish once grew to lengths of 6 feet and reached weights of 80 pounds. It was the top predator in the Colorado River system. Though the pikeminnow's diet consists primarily of other fish, fishermen caught them in earlier times by using mice, small birds and even prairie dogs as bait. Once Colorado pikeminnow were so abundant that they were fished commercially.
The razorback sucker is one of the largest suckers in North America. Named for the characteristic keel-edged hump just behind its head, it can grow to more than 13 pounds and reach lengths of 3 feet or greater. Once widespread throughout most of the Colorado River Basin from Wyoming to Mexico, its current range is limited and spotty.
The bonytail chub is also a member of the minnow family. With large fins and a streamlined body, the bonytail is the rarest of the four endangered fish. It is nearly extinct with no reproducing wild populations known.
The humpback chub is so named because of the hump behind its head. They can grow to 30 inches and may survive more than 30 years in the wild. Humpback chubs exist in the Little Colorado River of the Grand Canyon. Smaller numbers are found in the Upper Basin of the Colorado River.
All four fish evolved more than 3 million years ago, truly earning them the title of "native fish." All four have been significantly impacted by outside influences such as construction and operation of water projects. Water development and use have altered seasonal flow patterns and lowered temperatures, as well as created physical barriers to historic migration patterns. In addition, introduced non-native fish, such the pike, catfish, smallmouth bass and red shiners, proved superior competitors in the altered environment of the Colorado River to the detriment of the native fish. In the mid-1960s, stream segments were poisoned to limit native fish populations and to prepare for the introduction of sport fish. Other factors that have contributed to the historic decline include pollution and parasites. Among the chubs, hybridization also may be a factor.
In March 1994, the U.S. Fish and Wildlife Service designated critical habitat for the endangered fish. Large portions of both the Upper and Lower Basins were included. In the Lower Basin, the Service designated the Colorado River from Lee Ferry to Davis Dam, including Lakes Mead and Mohave, and from Parker Dam to Imperial Dam as critical habitat for the razorback sucker. Stretches of the river from Hoover Dam to Davis Dam, including Lake Mohave, and from the northern boundary of the Havasu National Wildlife Refuge to Parker Dam, including Lake Havasu, were designated as critical habitat for the bonytail chub. A number of tributary reaches were designated as well. Finally, a reach of the Colorado in the Grand Canyon was designated as critical habitat for the humpback chub.
In the Upper Basin, the cumulative designation essentially extends throughout most of the basin, as specific designated habitats for the various fish overlap in some cases and are distinct and separate in others. In general, the total designated habitats are: The Colorado upstream from Lake Powell to the confluences of the Gunnison and the Green; the Colorado continuing upstream to about Rifle, Colo., the Green upstream to the confluence with the Yampa River and then continuing up the Yampa to about Craig, Colo.; the White River from the confluence with the Green upstream to the Rio Blanco Reservoir in Colorado; and the Gunnison River upstream to the confluence with the Uncompahgre River near Delta, Colo. In addition the San Juan River has been designated from Lake Powell upstream to about Farmington, NM. With the Upper Basin, Utah contains the most critical habitat, followed by Colorado and New Mexico.
As part of its process, the Service prepared an economic analysis document and it analyzed whether its actions would interfere with constitutionally protected property rights and concluded that the designation of critical habitat did not pose significant takings implications. In its final rule, no areas were excluded from designation due to economic impacts. However, one Colorado River reach in the Lower Basin, from Davis Dam to Topock Marsh, was deleted due to the lack of biological importance to the bonytail chub.
Of considerable significant was the service's determination that economic impacts resulting from endangered species listing are not to be considered during critical habitat designation.
The Recovery Program for the endangered fishes in the Upper Basin is a multiparty effort designed to recover these fish populations while allowing water development to proceed in Wyoming, Utah, and Colorado. As with many other cooperative efforts, the recovery program was born of conflict.
In 1984, the Service convened a committee to resolve the inherent conflict between protection of the endangered fish and the need for future water development. A steering committee was formed with representatives of federal and state water develop and wildlife management agencies, water users and environmental organizations. Technical subcommittees were also formed to address complex biological and hydrologic issues. From this lengthy and intense fact-finding effort, a concept evolved of recovering the fish and protecting their habitat while allowing for water development.
The Recovery Program includes five elements:
(1) habitat management;
(2) habitat development and maintenance;
(3) native fish stocking;
(4) controlled non-native and sport fish management; and
(5) research, data management, and monitoring.
The Recovery Program covers water development profects with Endangered Species Act Section 7 compliance.
A recovery and implementation program for the endangered fish of the San Juan River is now in place. The goal of this effort between the Department of the Interior, the States of Colorado and New Mexico, the Navajo Nation, Southern Ute Tribe, Ute Mountain Ute Tribe, and the Jicarilla Apache Tribe is to protect the fish while allowing water development to proceed. The State of Utah has not signed the agreement to participate in this recovery and implementation program. The program is a condition of the reasonable and prudent alternative for the biological opinions under the Endangered Species Act for the Animas-LaPlata and Navajo Indian irrigation projects.
Numerous environmental protection, conservation and restoration efforts are ongoing in the Lower Colorado Region. Activities range from the very specific to those of a broad, multi-species conservation program that encompasses the entire lower Colorado River corridor.
A sampling of these programs follows:
In 1989, Reclamation formed the Native Fish Work Group, with the objective of conserving and helping recover the aging, fast disappearing population of the endangered razorback sucker. In addition to Reclamation, the NFWG includes the U.S. Fish and Wildlife Service, National Park Service, Nevada Department of Wildlife, Arizona Game and Fish Department, Arizona State University, and Biological Resources Division of the U.S. Geological Survey.
After inhabiting the Colorado River for millions of years, the razorback population had seriously declined because of changes brought about by the development of large-scale water management projects on the lower river, and by the introduction of non-native and highly predatory game fish. In 1989, the Lake Mohave population, the largest existing population remaining, was estimated at about 60,000 adults; in 1997, it was estimated at about 25,000 adults. Without help, this population was predicted to collapse by the turn of the century. To restore and maintain this population, and the species, NFWG biologists are capturing razorback larvae, and raising them in protected waters such as isolated coves, golf course ponds, and retrofitted fish hatcheries, where they are safe from predation. The NFWG's goal is to add 50,000 young razorbacks to Lake Mohave's existing population by the turn of the century; by the end of 1997, more than 10,000 fish will have been raised to a size where they can safely be returned to the lake. These fish, the spawn of the lake's wild population, will maintain the population's genetic diversity and viability.
Reclamation also works in partnership with other agencies to maintain and expand native riparian plant communities along the lower Colorado River. In cooperation with the Fish and Wildlife Service and National Park Service, native riparian plant nurseries have been established at three national wildlife refuges and at Lake Mead; plant material from these nurseries can be used to restore or enhance projects by any of the cooperating agencies. Reclamation and Fish and Wildlife also have established five different demonstration areas along the river, for the purpose of studying the biotic and abiotic factors influencing the survival and growth of native riparian species, and are working to revegetate approximately 200 acres of land along the river with native riparian habitat.
Reclamation also is involved in development of man-made wetlands in Arizona, Nevada and California. Reclamation helped the Eastern Municipal Water District in Southern California construct a system to reclaim, convey and blend wastewater with potable water for irrigation of agricultural lands, municipal and industrial uses and recreational lakes. Approximately 25 acres of demonstration wetlands were built to investigate their potential as alternatives to the construction of large, energy-intensive facilities needed to treat reclaimed water. The wetlands also provide fish and wildlife habitat and nesting grounds for waterfowl and shorebirds, as well as recreational and educational opportunities. In Nevada, Reclamation joined with others to develop the Boulder City Wetland Project. Completed in 1997, this project will demonstrate how reclaimed municipal wastewater can be used to restore habitat for threatened and endangered species and species of concern; provide educational opportunities; and allow research on improving water quality and restoring habitat for sensitive species. The wetland will receive Colorado River water, which will be blended with treated wastewater from the City's wastewater treatment plant. After flowing through the wetland system, the water will be used to irrigate turf at an adjacent Veteran's Cemetery, obtaining maximum benefit from the City's wastewater.
The Multi-Species Conservation Program is another major environmental effort underway in the Lower Colorado Region. This cooperative effort involves Federal agencies, the three Lower Basin States, Lower Basin Tribes, and environmental organizations, all working together toward the recovery of more than 100 Federal- or State-listed sensitive, threatened and endangered fish and wildlife species, and their habitats, along the lower Colorado River corridor. Planned for implementation over a 50-year period, the program's goals are: 1) recover listed species through habitat and species conservation and attempt to reduce the likelihood of additional species listings under the Endangered Species Act; 2) accommodate current water diversion and power production operations; and, 3) optimize opportunities for future water and power development.
In spring 1996, the Lower Colorado Regional Office initiated an extensive survey for the federally endangered Southwestern Willow Flycatcher. This small bird nests in riparian areas with dense stands of shrubs and trees like cottonwood and willows -- vegetation that once thrived along the lower Colorado River. Over the years, this habitat has been lost through river regulation and urban and agricultural development. Although fairly common at the turn of the century, scientists believe only an estimated 230 to 500 nesting pairs of this bird remain. Reclamation-led surveys of lower Colorado River sites representing the best willow flycatcher habitat from the Lake Mead delta to Yuma, Arizona, have documented more than fifty territorial pairs of birds and numerous nests - encouraging information, since many scientists thought the flycatcher no longer nested along the lower Colorado River. Additional surveys have shown the bird exists along other drainages as well. This effort, like a similar effort in Arizona, is helping biologists learn more about this endangered species and its status throughout the Lower Colorado Basin. Through these surveys, and through such efforts as the purchase of potential new habitat that will be forever protected from development, Reclamation is helping ensure the future and continued success of this species.