[Federal Register Volume 60, Number 187 (Wednesday, September 27, 1995)]
[Proposed Rules]
[Pages 49819-49821]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-23975]



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DEPARTMENT OF THE INTERIOR
50 CFR Part 17


Endangered and Threatened Wildlife and Plants; 90-Day Finding for 
a Petition to List Desert Redband Trout in the Snake River Drainage 
Above Brownlee Dam and Below Shoshone Falls as Threatened or Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.

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SUMMARY: The U.S. Fish and Wildlife Service (Service) announces a 90-
day finding for a petition to list the desert populations of interior 
redband trout (Oncorhynchus mykiss gairdneri) in the Snake River 
drainage above Brownlee Dam and below Shoshone Falls as a threatened or 
endangered species under the Endangered Species Act of 1973, as 
amended. The Service finds that the petition did not present 
substantial scientific or commercial information 

[[Page 49820]]
indicating that the petitioned action may be warranted because it fails 
to substantiate that these populations of redband trout constitute a 
distinct population segment.

DATES: The finding announced in this document was made on September 20, 
1995.

ADDRESSES: Data, information, comments, or questions concerning this 
petition should be submitted to the Field Supervisor, U.S. Fish and 
Wildlife Service, Snake River Basin Office, 4696 Overland Road, Room 
576, Boise, Idaho 83705. The petition, finding, and supporting data are 
available for public inspection, by appointment, during normal business 
hours at the above address.

FOR FURTHER INFORMATION CONTACT: Patricia Klahr, staff biologist (see 
ADDRESSES section) (telephone 208/334-1931).

SUPPLEMENTARY INFORMATION:

Background

    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 U.S. Fish and 
Wildlife Service (Service) make a finding on whether a petition to 
list, delist, or reclassify a species presents substantial scientific 
or commercial information indicating that the petitioned action may be 
warranted. To the maximum extent practicable, this finding is to be 
made within 90 days of receipt of the petition and must be promptly 
published in the Federal Register.
    On April 11, 1995, a petition dated April 3, 1995, was received by 
the Service from the Idaho Watersheds Project, Inc., Oregon Natural 
Desert Association, Oregon Natural Resources Council, Idaho Sporting 
Congress, Idaho Conservation League, Committee for Idaho's High Desert, 
Elko County Conservation Association, Nevada Wildlife Federation, and 
Dr. Don W. Johnson (petitioners). The petitioners requested the Service 
list the desert redband trout (Oncorhynchus mykiss spp.) in the Snake 
River drainage above Brownlee Dam and below Shoshone Falls as 
threatened or endangered under the Act. The Service accepts the 
taxonomic system proposed by Behnke (1992) and recognizes the interior 
redband trout as the subspecies Oncorhynchus mykiss gairdneri. An 
amendment to this petition, dated July 6, 1995, and received on July 7, 
1995, changed the species' range under consideration to exclude 
forested higher altitude watersheds and include lower elevation desert 
rivers and streams. The petitioners state that these populations of 
interior redband trout have been recognized as distinctive based on 
their physiological tolerance to severe desert environments and on 
their external appearance. Threats that were identified include 
degradation of riparian habitat resulting from land use practices and 
decreased stream flows due to irrigation withdrawals.
    The interior redband trout is designated a species of concern to 
the Service (formerly category 2 species, 59 FR 58982, November 15, 
1994). This designation includes taxa for which information in the 
Service's possession indicates that listing is possibly appropriate but 
for which the Service lacks sufficient information upon which to base a 
proposal to list as endangered or threatened.
    The Service has reviewed the petition, the literature cited in the 
petition, and other literature and information available in the 
Service's files. On the basis of the best scientific and commercial 
information available, the Service finds the petition does not present 
substantial information indicating that the petitioned action may be 
warranted because there is insufficient information to show that 
interior redband trout of the middle Snake River desert area are a 
distinct population segment under the Act.
    Within the trout species Oncorhynchus mykiss, Behnke (1992) 
includes three major groups composed of four subspecies. The petitioned 
populations of redband trout are found within the Columbia River basin 
east of the Cascade Mountains and are included by Behnke (1992) as part 
of O. m. gairdneri. This subspecies currently includes anadromous 
steelhead populations, populations adapted to lakes (kamloops trout), 
and resident stream populations. Behnke (1992) describes the 
subspecies' distribution as the Columbia River basin east of the 
Cascades to barrier falls on the Kootenai, Pend Oreille, Spokane, and 
Snake rivers; the upper Fraser River basin above Hell's Gate; and 
Athabasca River headwaters of the Mackenzie River basin. The historical 
range of the interior redband trout includes Idaho, Montana, Nevada and 
Oregon (56 FR 58815, November 21, 1991).
    There has been confusion regarding the taxonomic classification of 
interior redband trout (Behnke 1986, Behnke 1992), probably due to 
similar morphological and meristic characteristics with other rainbow 
and cutthroat trout species (Berg 1987). The taxonomy is further 
complicated by the subspecies' diversity and adaptability, as interior 
redband trout are found in high mountain streams as well as in arid 
desert drainages. A Service review of the literature and discussions 
with regional fisheries biologists reveals an ongoing debate about the 
definition of interior redband trout. Presently there appears to be 
general agreement that the interior rainbow trout ``complex'' includes 
redband trout of the Columbia basin east of the Cascade range up to 
barrier falls, and including anadromous steelhead, making the 
distribution of this subspecies wide and diverse.
    The petitioners state that redband trout in the Snake River 
drainage upstream of Brownlee Dam and below Shoshone Falls constitute a 
distinct vertebrate population segment because geographic and 
ecological isolation of the individuals have resulted in unique 
adaptations for survival in habitat unsuitable to other trout, as well 
as other genetic differences. Further, the external appearance of 
redband trout is distinctive, displaying characteristics of both 
rainbow and cutthroat trout.
    The petitioners did not present genetic data to support 
differentiation of ``desert'' redband trout from other populations of 
redband trout. Genetic information cited in the petition described 
genetic differences between interior redband trout, and trout of 
hatchery origin or coastal rainbow trout (O. m. irideus)(Wallace 1979, 
Leary et al. 1983, Sage et al. 1992, Williams and Shiozawa 1993). In 
addition, the physical appearance of redband trout is not unique to 
``desert'' redband trout (Behnke 1992), and therefore is not an 
indication of distinctness for redband trout from the Snake River 
drainage upstream of Brownlee Dam and below Shoshone Falls.
    Therefore, the petition does not provide any information to support 
the claim that significant ecological isolation has occurred such that 
this grouping of redband trout has evolved apart from the remainder of 
the subspecies. Specifically, no information was provided to indicate 
that the petitioned group of redband trout is distinct or discrete from 
the redband trout populations occupying hundreds of miles of habitat in 
the inland northwest. In addition, this petitioned group does not 
constitute a significant portion of the range of the interior redband 
trout.
    The Service concludes that the data contained in the petition, 
referenced in the petition, and otherwise available to the Service do 
not present substantial information that the petitioned action may be 
warranted. The Service will retain the interior redband trout as a 
species of concern and will continue to seek information regarding the 
status of, and threats to the subspecies. If 

[[Page 49821]]
additional data become available in the future, the Service may 
reassess the listing priority for this subspecies or the need for 
listing.

References cited

    A complete list of all references cited herein are available upon 
request from the Snake River Basin Office (see ADDRESSES section).

Author

    The primary author of this document is Patricia C. Klahr (see 
ADDRESSES section).

Authority

    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U. S. C. 1531 et seq.).

    Dated: September 20, 1995.
John G. Rogers,
Acting Director, Fish and Wildlife Service.
[FR Doc. 95-23975 Filed 9-26-95; 8:45 am]
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