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The Central Bear sub-basin (Idaho and Wyoming) of the upper Bear River basin is presently inhabited by 27 BRB populations (including 1 lake) occupying 77% of NF's historic habitat. (Table 6b). These occupied habitats occur within the Smith's and Thomas Fork's of the Bear River in Wyoming and Idaho (Binns 1981). These watersheds also contain eight populations on BLM lands. Overall popula- tion status within the sub-basins was indicated to be.at risk, stable. (ARS), with Wyoming populations (Bridger-Teton NF) estimated 95% .secure, stable. (SST) while Idaho populations (Caribou NF) were estimated 33% as Oat risk, stable. (ARS) and 67% in the categories of .unknown. to .at risk, declining. (ARD) (Table 16). Within the sub-basin, in Idaho portion of the upper Thomas Fork, three BRB populations occur, two of which also have occupied habitat in Wyoming (Bridger-Teton NF), but for purposes of this assessment reporting will be listed as separate populations, as identtfied by state wildlife agencies (personal communication Ron Remmick, Wyoming Dept. Game and Fish). Status of three BRB populations in Idaho are considered "at risk, declining. (ARD) due to human activities. The Idaho Department of Fish and Game and the Caribou National Forest have implemented a joint conservation strategy to conserve and protect these populations (Skully 1995). Wyoming BRB populations are being managed jointly under the interagency five-year management plan (1993-1997) which includes all populations on NFS and BLM lands in this sub-basin (Remmick et al 1994). Habitat condition and trend indicates that 95% of habitats are in good condition and 5% fair on the Bridger-Teton NF, while habitat trend is 100% stable on all streams (Table 17). Information on lands outside NF boundaries is incomplete, but that available indicates some is in fair to poor condition with a decreasing trend. Sedimentation is noted as affecting 100% of BRB populations. Other factors affecting habitat condition are dewatering (13%), and changes in stream morphology and lack of woody debris, both 14%. Land-use activities contributing to these factors were identified as grazing (91%) and road construction (68%). Rainbow trout occupy 100% of BRB population habitats in the Smiths and Thomas Forks, while brown trout and other hatchery cutthroat trout occupy 82% and 99% respectively of the same habitats (Table 9). The presence of these exotic fishes are viewed as a threat to all BRB Wyoming populations. However, previous genetic research has indicated the unique ability of this population to exist with limited introgression, a factor that is not present in most other BCT populations within the Bonneville Basin (Martin and Shiozawa 1982, Behnke 1980, 1992, Nelson 1990, Remmick 1994, Shiozawa and Evans 1995). The upper Bear River sub-basin in Utah, contains five known pure BRB populations all of which occupy habitat on the Wasatch-Cache NF (Tables 4,5). Current assessment information indicates about 352 historic stream miles with 70% occurring on NFS land. Current occupancy of BRB popula- tions is limited to only 1.9% of NF historic habitat. Occupancy indicates that BRB populations have been eliminated from about 80% of NF historic habitat upstream of Evanston, WY, and 91 % extirpated from total historic habitat. Within the sub-basin from Evanston downstream to the Central Bear sub-basin boundary, only one BRB population occupies NFS land (Wasatch-Cache NF). In this reach of the sub-basin, it is estimated, based on stream mileage and occupancy, that BRB populations have been extirpated in 98% of total historic waters, and 75% extirpated on NFS lands. Population status of all five BRB populations on the Upper Bear sub-basin is indicated to be "at risk, stable. (ARS) (Table 6b). Habitat condition on the Wasatch-Cache NF was indicated to be fair to poor with a stable, but tending toward declining trend. All five BRB populations were stream resident and trends in abundance were stable to declining while distribution was declining. Exotic fish, primarily rainbow and other cutthroat, were present in all occupied waters and viewed as a threat. Factors affecting habitat condition in the streams were sedimentation (1 OO%) , channel morphology changes (60%), increased water tempera- ture (100%), lack of woody debris (60%), and dewatering (60%). Activities affecting habitat condition were indicated to be grazing (100%), roading (80%), and logging (40%) (Table 15). 47