Ch1 Overview
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4 FOCAL AND TARGET SPECIES 4.1 Bull Trout (Salvelinus confluentus) 4.1.1 Background Reasons for Selection as Focal Species Globally, the bull trout has a G3 ranking: very rare and local throughout its range, or found locally (even abundantly at some of its locations) in a restricted For more information on the range, or vulnerable to extinction throughout its range because of other factor(s). federal listing, go to the The federal government listed bull trout (Salvelinus confluentus) in the coterminous USFWS bull trout website at: United States as threatened on November 1, 1999 (64 FR 58910) (go to: http:/ http://pacific.fws.gov/bulltrout/ /pacific.fws.gov/bulltrout/). Earlier rulemakings had listed distinct population segments of bull trout as threatened in the Columbia River and Klamath River (June 1998; 63 FR 31647, 63 FR 42757), and Jarbidge River basins (November The lexicon for describing bull 1999; 64 FR 17110). trout population units has The USFWS recovery priority number for bull trout in the contiguous evolved. In the USFWS Draft United States is 9C, on a scale of 1 to 18, indicating that (1) taxonomically, these Bull Trout Recovery Plan populations are distinct population segments of a species; (2) the populations are (USFWS 2002a), the bull subject to a moderate degree of threat(s); (3) the recovery potential is high; and trout population units are hierarchically described, from (4) the degree of potential conflict during recovery is high (USFWS 2002). the Columbia River Basin The U.S. Forest Service lists bull trout as a sensitive species, primarily to distinct population segment emphasize habitat protection. The Idaho Panhandle National Forests have named (DPS) at the largest scale, to bull trout as Management Indicator Species (MIS) in their Forest Plan to guide recovery units, to core areas, stream and riparian management and to monitor progress toward achieving Forest each of which are comprised of one to many local populations. Plan objectives. Forest Plan standards must be met regarding habitat needs of The term “subpopulation” these species, thereby ensuring a quality environment for other aquatic organisms, although used in places in this such as sculpins, amphibians, and aquatic insects (USFS 1998). document, was considered less In Montana, bull trout have received a ranking of S2, meaning they are useful and the use of this term considered imperiled because of rarity or because of other factor(s) making them was officially discontinued by the Bull Trout Recovery Team. very vulnerable to extinction throughout their range. Montana Department of For more thorough definitions Fish, Wildlife, and Parks (MFWP) has designated them a species of special concern of these and other terms used in due to their limited distribution, sensitivity to environmental disturbances, this section, go to Appendix 96. vulnerability to hybridization and/or competition with other fish species, and risk of over-exploitation. 203 FOCAL SPECIES: BULL TROUT The Kootenai Tribe of Idaho and the Confederated Tribes of the Salish and Kootenai consider bull trout a sensitive species and an important cultural resource. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) determines the national status of wild Canadian species, subspecies and separate populations suspected of being at risk. In British Columbia, bull trout are listed as an intermediate priority candidate species (COSEWIC 2003). COSEWIC candidate species are those that are suspected of being in some category State, federal and tribal of risk of extinction or extirpation at the national level, before being examined biologists in Montana have through the status assessment process. The B.C. Conservation Data Centre has done extensive work on bull trout. Results from these efforts, blue-listed bull trout in British Columbia, which means they are a species which have resulted in some of considered to be vulnerable or of special concern because of characteristics that the best and most detailed make them particularly sensitive to human activities or natural events (BC Ministry information available for bull of Sustainable Resource Management 2003). trout in the Montana portion The British Columbia Forest Practices Code includes an “Identified Wildlife of the Kootenai Subbasin, are entered onto the Montana Management Strategy” that lists wildlife, wildlife habitat areas and associated Fisheries Information System landscape units. “Identified Wildlife” lists species considered to be at risk (e.g. (MFISH) database accessible endangered, threatened, vulnerable or sensitive) and that require management of on the internet at: http:// critical habitats in order to maintain populations and/or distributions (BC nris.state.mt.us/scripts/ Ministry of Forest 1997). esrimap.dll?name= MFISH&Cmd=INST. Bull trout are good indicators of aquatic ecosystem health. They have relatively strict habitat requirements. They require high quality, cold water; high levels of shade, undercut banks, and woody debris in streams; abundant gravel in riffles with low levels of fine sediments; stable, complex stream channels; and For various bull trout reports connectivity among and between drainages (USFWS 2002). These requirements from the B.C. Ministry of make them a good indicator of the health of an aquatic environment. Because Water, Land, and Air bull trout use the entire aquatic system in the subbasin, impacts in any single Protection, go to Appendix 113. component can potentially affect bull trout. Because of this and their status, we have selected bull trout as a focal species in this assessment. 1 Summary of population and current distribution data In the final ESA listing rule for bull trout, five subpopulations were recognized within the Kootenai River Subbasin (USFWS 1998). These included three portions of the mainstem system: (1) Upper—upstream from Libby Dam, (2) Middle— from Libby Dam downstream to Kootenai Falls, and (3) Lower— downstream 1 As mentioned previously, metapopulations are composed of one or more local populations. As in the Bull Trout Recovery Plan, in this assessment bull trout have been grouped into distinct population segments, recovery units, core areas and local populations. Core areas are composed of one or more local populations, recovery units are composed of one or more core areas, and a distinct population segment is composed of one or more recovery units. 204 FOCAL SPECIES: BULL TROUT from Kootenai Falls through Idaho to the United States/Canada border. The two disconnected subpopulations (referred to as disjunct by the Montana Bull Trout Scientific Group), in Bull Lake (MBTSG 1996b) and Sophie Lake (MBTSG 1996c), were considered separate subpopulations. At the time of listing, all Kootenai River bull trout subpopulations were considered to have unknown status and population trend, and the Sophie Lake subpopulation was considered to be at risk of stochastic For a map showing current bull trout distribution and extirpation due to its single spawning stream and small population size. restoration and core habitat In its Bull Trout Draft Recovery Plan, the USFWS identified 27 recovery areas within the Montana units based on large river basins and generally following existing boundaries of portion of the Kootenai, go to conservation units for other fish species described in state plans, where possible. Appendix 52. The Kootenai River Recovery Unit forms part of the range of the Columbia River population segment. The Kootenai River Recovery Unit includes 4 core areas (figure 4.1) and about 10 currently identified local populations. In recent years, emphasis for the Kootenai River Subbasin has been placed USFS bull trout distribution maps for the Kootenai 2, 3 on determining abundance through redd counts . Table 4.1 summarizes the Subbasin portion of the Idaho status of redd count information from 1996 to 2000 for the four core areas in the Panhandle and Kootenai Kootenai River recovery unit. Redd counts represent an unknown but substantial National Forests are included portion of the possible spawning population. Three of the four core areas have an in Appendix 1. established history of redd count trend information for migratory fish. Eight streams in the United States and three in Canada are now being monitored, with index redd counts conducted on an annual basis. Table 4.2 summarizes this information. In addition, six bull trout redds were counted in Goat Creek (a tributary of Callahan Creek, Montana) in 2003, the first year this stream was surveyed (A. Rief, USFS, unpublished data). Information for the Idaho portion of the subbasin is presented in tables 4.3 and 4.4. Redd counts have traditionally been conducted only for migratory fish. In some drainages, there are likely to be additional resident bull trout spawners whose redds are smaller than those of migratory fish, therefore difficult to identify in streams where brook trout exist. They have not been included in these totals. On the Wigwam River, five permanent monitoring sites were established in 2000 to evaluate juvenile abundance (Cope and Morris 2001). Juvenile abundance has also been monitored at three sites on Skookumchuck Creek for two years (Cope 2003 and Cope 2004 in prep), two sites on the White River, and at 2 The Bull Trout Draft Recovery Plan states: Because of the large size of the migratory fish and the geology of the streams (which generally makes the redds easy to recognize), redd counts (Spalding 1997) have been shown to provide a repeatable method of indexing spawner escapement in many streams in this recovery unit (Rieman and McIntyre 1996). However, several authors have cautioned that redd counts should not be relied upon as the sole method of population monitoring (Rieman and Myers 1997, Maxell 1999) and may, in fact, lead to erroneous conclusions about population status and trend. 3 Adapted from the Bull Trout Draft Recovery Plan (2003). 205 FOCAL SPECIES: BULL TROUT For bull trout information in the Kootenai Subbasin in British Columbia, go to: http:/ /srmwww.gov.bc.ca/aib/ For an electronic library of aquatic information (including reports pertaining to bull trout) for the B.C.