7994

• UCREFRP Catalog Number: 7994
• Author: Duff, D. A., Tech. Ed.
• Title: Conservation Assessment For Inland Cutthroat Trout, Distribution, Status and Habitat Management Implications.
• USFW Year: 1996.
• USFW - Doc Type: \
• Copyright Material: NO

Status of BCT population is indicated in tables for each population by their geographic area. Overall
population status reported by this current assessment, as reported by state and federal managers,
indicate 72% of BCT populations are in the "secure, stable" (SST) to "secure, expanding" (SEX) status
(30% SEX; 42% SST) and 25% in "at risk, stable" (ARS) to "at risk, declining" (ARD) status (19% ARS;
6% ARD) The status of 3% of the populations was indicated as "unknown., Again, while overall status
appears encouraging primarily due to BRB and SB population recovery efforts, the WB and NB
populations show cause for concern as noted by assessment within their specific geographic
sub-basin area. However, the BRB populations, which show close-relatedness to the Yellowstone
cutthroat trout, as noted earlier, were to be classified as a separate subspecies in the future, the total
numbers of remaining pure BCT within the basin proper would take on added importance and value
for protection.

Western Bonneville

The assessment area includes that portion of the West Desert in Utah from the Raft River Range on
the north to the Snake Range on the south including the Snake Valley portion of Pleistocene Lake
Bonneville. Included within this area are portions of Idaho (the Black Pine Range and Northern Great
Salt Lake Desert sub-basin) and portions of Nevada (the Pilot Range - Thousand Springs sub-basin
and the Snake Range, and the Hamlin - Snake Valley sub-basin). Also included, for the purposes of
this assessment are the isolated desert basins west and southwest of the Great Salt Lake with the
Stansbury - Sheeprock Range on the east border. Four National Forests (Sawtooth, Wasatch-Cache,
Uinta and Humboldt NF's) occur within portions of this area. This area encompasses nine sub-basins,
seven of which the Western Bonneville cutthroat trout (WB) was present historically (Table 2).

Presently, the WB occupies only two sub-basins, both in the Snake Valley Bay arm of Lake Bonneville.
The WB has been extirpated in 78% of the major sub-basins of its historical occurrence. Only two
populations of WB occupy historic habitat in these two sub-basins, one on the Humboldt National
Forest (HNF), Mt. Moriah Division, Nevada, and one on BLM land in the Deep Creek Range, Juab
County, Utah. An additional three WB populations occupy stream habitat in the Spring-Steptoe Valley
sub-basin, Nevada, outside the Bonneville basin. These transplanted populations occur in two
streams on the west slope of Mt. Wheeler, Great Basin National Park (NPS) and HNF, and the other
on one BLM stream to the north of Ely, Nevada. WB populations in the remaining three NF's, in the
west desert sub-basins, have been extirpated (Sawtooth, Wasatch-Cache, and Uinta NF's). In the
Bonneville basin only 6% of BCT on NFS lands are WB populations. The WB accounts for only 5%
of total BCT populations occupying all lands in the Bonneville Basin.

Of an estimated 427 historic perennial stream miles in the WB sub-basins less than one percent
(0.009) is occupied by two populations on the HNF (Tables 6, 6a). This amount includes an estimated
total 277 historical stream miles in the Snake Valley sub-basins (56.5 miles on HNF), 70 stream miles
in three sub-basins adjacent to the Raft River Black Pine Ranges (27.5 miles on Sawtooth NF) and
80 stream miles partially in four sub-basins surrounding the Stansbury - Sheeprock Range (49 miles
on Uinta NF and 31 miles on Wasatch-Cache NF).

Based on historic perennial stream occurrence, the assessment estimates that 90% of those stream
miles contained WB in all suitable waters; now 99% of the WB populations have been extirpated in
perennial streams in the seven WB sub-basins. Existing streams on the four NF's have an estimated
132 stream miles, of which only 3.2% is occupied by two WB populations. The WB is extirpated on
96% of NF streams on 4 national forests. There is little historic information that quantifies trout
abundance; most historic references provide an indication that trout were common in many perennial

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