Endangered and threatened species: Findings on petitions, etc.— Rio Grande cutthroat trout,


[Federal Register: September 14, 1998 (Volume 63, Number 177)]

[Proposed Rules]

[Page 49062-49063]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 90-Day Finding for a Petition to List the Rio Grande Cutthroat Trout

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.

SUMMARY: The Fish and Wildlife Service (Service) announces a 90-day finding for a petition to list the Rio Grande cutthroat trout (Oncorhynchus clarki virginalis) as endangered under the Endangered Species Act of 1973, as amended. The Service finds that the petition did not present substantial information indicating that listing this subspecies may be warranted.

DATES: The finding announced in this document was made on August 22, 1998.

ADDRESSES: You may submit any data, information, comments, or questions concerning this finding to the Field Supervisor, New Mexico Ecological Services Field Office, 2105 Osuna NE, Albuquerque, New Mexico 87113. Members of the public may review the petition finding, supporting data, and comments, by appointment during normal business hours at the above address.

FOR FURTHER INFORMATION CONTACT: Jennifer Fowler-Propst, Field Supervisor, New Mexico Ecological Services Field Office, at the above address (505/761-4525).



Section 4(b)(3)(A) of the Endangered Species Act (Act) of 1973, as amended (16 U.S.C. 1531 et seq.), requires that the Service make a finding on whether a petition to list, delist, or reclassify a species presents substantial scientific or commercial information to demonstrate that the petitioned action may be warranted. The Service is required to base the finding on all information available at the time the finding is made. To the maximum extent practicable, the Service must make this finding within 90 days of the date the petition was received, and promptly publish a notice in the Federal Register. If the Service finds that substantial information was presented, the Service also is required to promptly commence a review of the status of the species involved if one has not already been initiated under the Service's internal candidate assessment process.

The Service has made a 90-day finding on a petition to list the Rio Grande cutthroat trout (Oncorhynchus clarki virginalis) as endangered. Kieran Suckling, Director of the Southwest Center for Biological Diversity, submitted the petition, dated February 17, 1998. The Service received the petition on February 25, 1998. Additional petitioners included the Biodiversity Legal Foundation, Carson Forest Watch, Ancient Forest Rescue, and Southwest Trout.

The petitioners state that habitat destruction and degradation have reduced the current distribution of the subspecies to approximately 5% of its historical range; existing populations are small and isolated; habitat destruction and degradation from livestock grazing, logging, road construction, and mining continue to threaten the subspecies; and stocking of nonnative, closely related species such as the rainbow trout (Oncorhynchus mykiss) has replaced many of the historical populations of the native species with hybrids. The petition further states that these factors continue to threaten the stability and existence of the Rio Grande cutthroat trout.

The Service has reviewed the petition and other literature and information available in the Service's files, and

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consulted with species experts concerning the current status of the Rio Grande cutthroat trout. Much of the information that the Service reviewed updated and corrected information which had been provided in the petition. On the basis of the best scientific and commercial information available, the Service finds the petition does not present substantial information that listing this subspecies may be warranted.

Approximately 200 populations of Rio Grande cutthroat trout inhabit cold headwater streams in the Rio Grande, Pecos River, and Canadian River drainages in Colorado and New Mexico (Alves 1998, Stumpff 1998). The petitioners cited only 92 extant populations. The New Mexico Department of Game and Fish and Colorado Division of Wildlife both prohibit stocking of nonnatives within the range of the Rio Grande cutthroat trout. In addition, all three national forests (Rio Grande, Santa Fe, and Carson) on which the subspecies occurs, have incorporated the State management plans into their forest plans. The States and national forests are implementing programs of stream inventory, protection of the Rio Grande cutthroat trout through removal of nonnatives, and repatriation of the native subspecies into historical waters. These actions are effectively addressing the protection of the subspecies from potential hybridization with rainbow trout.

Although habitat degradation has reduced the range of this once widely distributed subspecies, an adequate amount of habitat (4,500 to 5,000 miles (mi) of streams still capable of supporting trout) remains and can be included in management for the Rio Grande cutthroat trout. Of these stream miles, the subspecies currently occupies 480 mi of stream and 1,120 acres (ac) of lake habitats in Colorado; and 260 mi of stream habitat in New Mexico. Not all of the habitats potentially inhabited by the Rio Grande cutthroat trout have been surveyed; thus, the total number of existing known populations is considered to be a minimum.

Activities such as livestock grazing, road construction, and logging were primary factors in the constriction of the Rio Grande cutthroat trout's historical range and continue to impact streams and riparian habitats where measures to limit those impacts are lacking. However, the New Mexico Department of Game and Fish has found that the watersheds surveyed are in fair to good condition. Many watersheds have not been analyzed but are scheduled for such work by the State in cooperation with the U.S. Forest Service. In Colorado, 82 populations of the Rio Grande cutthroat trout occupy streams in watersheds that have been classified as either relatively pristine (Class I), or exhibiting only a minor degree of impact (Class II). These conditions do not support a contention that the existing populations of the subspecies are vulnerable to extirpation based on watershed or habitat quality.

In summary, the management objectives of both States, set forth in the respective management plans formulated for the Rio Grande cutthroat, indicate that continued management and conservation emphasis will be placed on the habitat and population stability of the subspecies. The Service believes that the current population is secure and likely to improve with active management. Thus, the Service has determined that the petition to list the Rio Grande cutthroat trout did not present substantial information indicating that the petitioned action may be warranted.

References Cited

Alves, J. 1998. Status of Rio Grande Cutthroat Trout in Colorado. Colorado Division of Wildlife. Denver, Co. 10 pp. Stumpff, W. K. 1998. Rio Grande Cutthroat Trout Management. Final Report. Federal Aid Grant F-60-M. Project No. 11. 14 pp.

Author: The primary author of this document is Jennifer Fowler- Propst, New Mexico Ecological Services Field Office (see ADDRESSES section).


The authority for this action is the Endangered Species Act (16 U.S.C. 1532 et seq.).

Dated: August 22, 1998. Jamie Rappaport Clark, Director, Fish and Wildlife Service.

[FR Doc. 98-24504Filed9-11-98; 8:45 am]