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<br />trout were taken from the Uttle Bighorn drainage upstream of the town but not downstream (personal <br />communication Robbin Wagner, USFWS). <br /> <br />The amount of historic Yellowstone cutthroat trout riverine habitat within Montana was estimated at <br />1,927 miles (Table 9). In addition to riverine environments, 2 lakes were identified as being historically <br />occupied. Uttle historical information is available for the Montana portion of Yellowstone cutthroat <br />range. Evermann (1891) as part of his investigation of potential hatchery sites visited Reese Creek, <br />a small tributary of the Yellowstone River just north of Yellowstone National Park and Botteler Springs <br />which is located on the westside of the Yellowstone River about 25 miles south of Uvingston, <br />Montana Even though Evermann did not specifically mention trout being present at the sites visited, <br />he did make the comment ,he Yellowstone River in the immediate vicinity has an abundance of trout, <br />many individuals of very large size being noticed". <br /> <br />Current occupancy estimates indicate that approximately 625 miles of stream habitat are presently <br />inhabited by Yellowstone cutthroat trout (Table 9). Based on this information, approximately 32% of <br />the historic riverine habitat was felt to be currently occupied by Yellowstone cutthroat trout. Of the <br />three States, Montana's assessment of current occupancy of historic habitat is likely the most <br />accurate. Subsequent to Hadley's (1984) status report, a concerted effort, beginning in 1986, was <br />initiated to more accurately define where "genetically pure" populations occur (Table 6). To date, 98 <br />samples have been sent to the University of Montana for electorphoretic analysis and 65 streams <br />have been identified as having genetically pure populations of Yellowstone cutthroat trout. It is likely <br />that the genetic validation completed to date covers the majority (80 to 90 %) of current riverine <br />populations. Concern for riverine populations led to the formation of an informal working group of <br />fishery professionals who drafted a management glJide for Mure protection and conservation of <br />Yellowstone cutthroat within the Yellowstone River basin (In preparation, Montana Department of <br />Fish, Wildlife and Parks and Wyoming Game and Fish Department). The majority of riverine cutthroat <br />trout populations were determined to be stable but at risk (Table 10). All sub-basins supported exotic <br />species and in eleven (11) sub-basins exotic trout were viewed as a threat to Yellowstone cutthroat <br />trout. Recent expression of the threat exerted by introduced trout has occurred in several instances <br />within the Montana. Competing species such as brown trout (e.g. Bad Canyon Creek, Stillwater <br />drainage) and brook trout (e.g. Smith Creek, Shields River drainage) have replaced cutthroat to a <br />significant degree in many streams. Within Little Mission Creek there has been recent (since 1986) <br />rainbow trout hybridization of the genetically pure cutthroat population probably as a result of rainbow <br />trout movement from a private pond. Yellowstone cutthroat trout (genetically pure) from McBride Lake <br />have been a major part of Montana's mountain lake fishery management and these lake populations <br />will playa valuable role in future conservation. Within Montana, 143 mountain lakes currently support <br />discrete populations which have a high probability of being genetically pure. To date only a few lake <br />populations have been analyzed for genetic status and the results have indicated that a very high <br />percentage are genetically pure Yellowstone cutthroat trout. <br /> <br />Historic references relating to habitat conditions are virtually non-existent. Naturalists who visited <br />Montana made little reference to habitat condition. It is reasonable to assume that historic habitat <br />conditions were favorable for trout and very similar to those observed in Idaho and Wyoming. Current <br />habitat, within Montana, indicates that a substantial number of sub-basins have habitat conditions <br />rated as good to poor (Table 11). A significant number of the sub-basin assessments also indicated <br />that the trend in habitat condition was either stable or declining. It is important to note that information <br />contained in Tables 7 and 8 may at times seem inconsistent. For some sub-basins more than one <br />condition and/or trend was identified and for other sub-basins condition and/or trend may have been <br />omitted. The same is true for the information associated with factors linked to degradation and the <br />land-use activities associated with those factors. Factors affecting aquatic habitat quality and some <br />of the associated land uses are identified in Table 12. <br /> <br />21 <br />