“WESTSLOPE” CUTTHROAT TROUT Oncorhynchus Clarki Lewisi

“WESTSLOPE” CUTTHROAT T ROUT Oncorhynchus clarki lewisi Original prepared by Stephen Bennett

Species Information because water levels were higher during the glacial retreat and/or barriers formed following glacial Taxonomy retreat as the land mass rebounded. Westslope Cutthroat Trout were isolated above these barrier The Westslope Cutthroat Trout is one of 14 sub- falls and survived in refuge areas in Montana, Idaho, species of interior Cutthroat Trout, Oncorhynchus and Washington during the last ice age. Rainbow clarki, native to western North America (Behnke Trout (Oncorhynchus mykiss) appear to have been 1992). Westslope Cutthroat Trout were first restricted to the lower Columbia River during this described by the Lewis and Clark expedition in the period and did not occur above the barrier falls Missouri River, near the present-day city of Great allowing Westslope Cutthroat Trout to colonize Falls, Montana in 1805 (Behnke 1992). However, as inland portions of North America in isolation from recently as the 1970s, there was confusion regarding Rainbow Trout (Behnke 1992). Westslope Cutthroat the appropriate taxonomic classification of the Trout were also able to move between some drainage Westslope Cutthroat Trout (Roscoe 1974). Today, systems likely through headwater transfers. These Westslope Cutthroat Trout are considered a distinct events are critical in understanding cutthroat taxonomic form, distinguishable from the conservation as Westslope Cutthroat Trout evolved Yellowstone (O. clarki bouvieri) and other subspecies independent from Rainbow Trout and lack innate of cutthroat trout on the basis of spotting pattern, isolating mechanisms that allow them to co-exist karyotype (66 chromosomes), and biochemical (Behnke 1992). characteristics (Behnke 1992). The subspecies O. clarki alpestris, known as the “Mountain” Description Cutthroat Trout, is considered a synonym of Westslope Cutthroat Trout; it occurs as disjunct Cutthroat Trout get their common name from a stocks ranging from eastern Oregon into British distinctive red slash that occurs just below both sides Columbia (Trotter 1987; Behnke 1992). of the lower jaw. Westslope Cutthroat Trout have small irregular-shaped spots along their back, dorsal, Westslope Cutthroat Trout live in a variety of and caudal fins. Few spots occur below the lateral different stream conditions, from heavily glacial line on the anterior of the body. Adults typically systems to clear, stable, spring-fed streams, and exhibit bright yellow, orange, and/or red colours many populations are isolated from one another by along the ventral area, especially among males natural barriers and watershed divisions. As a result, during the spawning season. Typically they are silver there are many distinct forms in British Columbia with yellow, green, blue, or brown hints on the back; and they exhibit a high degree of within-species however, overall body colour can vary widely and diversity. reflects the colour of the substrate and water. Fish in The present distribution of interior Cutthroat Trout turbid and/or glacial fed streams with moderate to was determined approximately 70 000 years ago by high gradients (e.g., Akolkolex River) tend to be the formation of barrier falls on the Kootenay, Clark paler and have fewer but larger spots with narrow Fork, Pend Oreille, and Spokane rivers (Behnke body profiles, while fish in clear streams with low 1992). Westslope Cutthroat Trout were able to gradients (e.g., St. Mary River) have heavier smaller colonize above what are now major barrier falls spotting and rounder body profiles.

1 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 1 2 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Distinguishing characteristics include the presence introduced in small headwater lakes throughout the of basibranchial teeth (Rainbow Trout lack these) upper Columbia and Arrow Lakes region of the and the upper jaw extends back past the hind margin lower Columbia watershed and the upper and lower of the eye (McPhail and Carveth 1992). Westslope Kootenay river systems. Other scattered introduc- Cutthroat Trout adults rarely exceed an overall tions have occurred in the Kettle River system, the length of 500 mm in lake- or stream-dwelling upper Shuswap river system and the upper Murray populations (Shepard et al. 1984; Westslope Fisheries River system (Peace drainage) (G. Norris, pers. 2003; J. Baxter, pers. comm.). For example females comm.) Other unconfirmed introductions have were found to be larger and weigh more than males likely occurred (McPhail and Carveth 1992). in the Elk and Wigwam rivers (adult females = McPhail and Carveth 1993 indicate that Westslope 396 mm [375–421 ± 1.5], 933 g [800–1100 ± 116.9]; Cutthroat Trout have been introduced into the adult males = 371 mm [336–422 ± 2.8], 700 g [450– Similkameen drainage (page 66), but that “natural 1200 ± 223.6]; Westslope Fisheries 2003). Similar populations are absent…” (page 77). average fish size was observed n the Wigwam River (J. Baxter, pers. comm.). Forest regions and districts Northern Interior: Peace (introduced population in Distribution Murray River) Southern Interior: Arrow Boundary (scattered/ Global introduced), Columbia (isolated/introduced), The range of Westslope Cutthroat Trout is the most Kootenay Lake (scattered/introduced), Okanagan geographically widespread among the 14 subspecies Shuswap (isolated/introduced), Rocky Mountain of interior Cutthroat Trout (Behnke 1992). The (native/introduced) Westslope Cutthroat Trout is native to southeastern Ecoprovinces and ecosections British Columbia, southwestern Alberta, western SBI: SHR (introduced) Montana, northern Idaho, and small disjunct SIM: BBT, CCM, COC, CPK, EKT, ELV, EPM, FLV, populations occur in parts of Washington, Oregon, MCR, NKM, SCM, SFH, SHH, SPK, SPM, and Wyoming (McPhail and Carveth 1992; UCV Mayhood 1999; USFWS 1999). The historic distri- SOI: OKR (introduced) bution of Westslope Cutthroat Trout is not exactly known but is thought to have occurred west of the Biogeoclimatic units Continental Divide in several tributaries to the AT, BG, ESSF, ICH, IDF, MS Columbia River, including the upper Kootenay River, through northwest Montana, and into northern Broad ecosystem units Idaho (Behnke 1992). East of the Continental FS, IN, LL, LS, OW, SP, WL Divide, the historic distribution includes the head- Elevation waters of the South Saskatchewan River drainage (United States and Canada); and the entire Missouri 450–2300 m River drainage upstream from Fort Benton, Life History Montana, and extending into northwest Wyoming (Behnke 1992). Diet and foraging behaviour British Columbia Like most trout, the Westslope Cutthroat Trout are an opportunistic forager and, without competition The largest contiguous range of native Westslope from other trout species, they feed on the most Cutthroat Trout is in the upper Kootenay and abundant food sources available. In general, they Flathead River systems with disjunct populations feed on aquatic and terrestrial macroinvertebrates scattered throughout the lower Kootenay, lower such as chironomids, caddisflies, mayflies, stoneflies, Columbia watersheds. The species has been widely

3 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 3 water boatmen (Corixidae), ants, and grasshoppers is not protected by the adults. The eggs incubate in (Alger and Donald 1984; Liknes and Graham 1988; the gravel for 6–7 weeks. They spend an additional Moore and Gregory 1988b). In lakes, zooplankton 1–2 weeks in the interstitial space in the gravel before also make up an important component of their the fry emerge from the gravel usually peaking in diet (Liknes and Graham 1988). Other fish and mid-July through early August (Griffith 1972; even small mammals can be preyed upon Northcote and Hartman 1988). The fry then either opportunistically. migrate to other habitat or rear in their natal stream. When feeding in streams Westslope Cutthroat Trout Site fidelity usually depend on drifting aquatic insect larvae. They often feed most at dawn and dusk which Site fidelity is poorly understood for most British corresponds to an increased density of downstream Columbia populations. It is generally accepted that invertebrate drift. Adult fish tend to occupy the best most adults return to the natal stream to spawn and habitat such as deep pools and runs where there is then return to a relatively small home range area in abundant cover and low to moderate gradients. either a large stream or lake for the remainder of the Griffith (1972) found that the age of Westslope year (Behnke 1992). However, there appears to be a Cutthroat Trout was positively correlated to the wide variety of site fidelity strategies between depth of water they occupied. Juvenile fish are disjunct populations and some times within usually forced to feed in less optimal habitat such as individuals of the same population. A tagged male shallow riffles and glides. and female that entered a spawning tributary at the same time returned to the same mainstem location Reproduction they were captured in and overwintered there (Westslope Fisheries 2003; A. Prince, pers. comm.). Westslope Cutthroat Trout typically reach maturity However, repeat spawners in the Blackfoot River at different ages depending on local conditions and spawned >3 km from the previous spawning site and genetic stock. Age at sexual maturity has been showed no fidelity to pre-spawning mainstem reported from 2 to 6 years (Brown 1971; Lukens location (Schmetterling 2001). Water flows were 1978; Liknes and Graham 1988; Behnke 1992). different between years during the Blackfoot study Males tend to mature a year sooner than females which may have influenced spawning site selection; (Behnke 1992). Downs et al. (1997) reported length however, the author suspected that the abundance of was a better predictor of maturity than age which spawning habitat available may have been a more suggests that in streams with higher growth rates, significant factor on spawning site selection. fish mature earlier. Adults begin to display spawning colours in March and April and disperse to spawning Home range streams in May and June. Spawning can occur from April through August but tends to peak in late May Home range size is highly variable and dependent on through to mid-June (Ford et al. 1995; Henderson et life style (i.e., adfluvial, fluvial, or resident). In al. 2000; Corbett 2001). Populations in headwater general, resident fish would have smaller home streams spawn later, usually peaking in mid July ranges than adfluvial or fluvial forms. Spawning (Northcote and Hartman 1988). They may repeat migrations can exceed 150 km (Bjornn and Mallet spawning in successive years depending on local 1964; Shepard et al. 1984). The mean home range of conditions and repeat spawners can be upwards of Elk River fish based on year 2000 radio-telemetry 70% of the spawning population (Liknes and results was 6.19 km (range: 1.6–16.9). More recent Graham 1988). observations on the Elk River have discovered adults moving more than 50 km upstream during the fall Spawning redds are constructed by the female who is from summer feeding areas to wintering pools attended by one or more males. Once the eggs are (A. Prince, pers. comm.). In the Wigwam River (a fertilized they are covered by the female and the redd tributary to the Elk River) adults were also observed

4 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 traveling large distances between spawning and Important habitats and habitat features wintering sites and, in one case, traveled 103 km Spawning (Baxter and Hagen 2003). Populations in high elevation streams with high gradients and numerous Spawning habitat for this species varies depending barriers are likely more sedentary. on the available habitat and presence of competitors, but usually occurs in low-gradient stream reaches Movements and dispersal that have gravel substrate ranging from 2 to 75 mm in diameter, water depths near 0.2–0.40 m, and Fluvial and adfluvial forms have been recorded to mean water velocities from 0.25 to 1.05 m/s move large distances (>25 km) during migrations (Shepard et al. 1984; Ford et al. 1995; Westslope related to spawning, feeding, or other habitat Fisheries 2003). Cover near spawning habitat is requirements (Bjornn and Mallet 1964; Shepard et important for adult fish to hold in before beginning al. 1984; A. Prince, pers. comm.). For example, they spawning and to escape predators (Corbett 2001; often move from shallow summer feeding areas to Westslope Fisheries 2003). deep pools for overwintering (Brown and Mackay 1995; Westslope Fisheries 2003). Movement is also Westslope Cutthroat Trout often spawn in small associated with water temperature with fish begin- clear tributaries with low-gradients, gravel sub- ning to move to spawning areas when mean average strates, stable flows, low sediment loads, and temperatures reach 7–10°C. Adults tend to disperse temperatures around 7–10°C (Behnke 1992; Ford in the summer after spawning and then begin to et al. 1995; McIntyre and Rieman 1995). However, congregate in the fall beginning around October 13 of 20 fish tagged in the Elk River in 2001 (65%) when they move in to wintering habitat (Brown and spawned in the main Elk River. The 2001 spring Mackay 1995; Brown 1999; Hilderbrand and freshet was significantly lower than normal which Kershner 2000; Westslope Fisheries 2003). Fish may have influenced the selection of spawning areas. remain in wintering habitat for 4–5 months and Newly deposited gravel substrate, in either tribu- movement is usually restricted to <1 km within taries or mainstems, may be critical for spawning wintering habitat (Brown 1999; Westslope success (Westslope Fisheries 2003). Baxter and Fisheries 2003). Hagen (2003) found that mainstem habitat was used almost exclusively for spawning in the Wigwam Westslope Cutthroat Trout may move relatively little River, and that stream margins and/or side channels in stream reaches that have numerous pools, whereas were of particular importance. movement can be more extensive in stream reaches with few pools (McIntyre and Rieman 1995). There Rearing and foraging are also indications that groundwater springs may play an important role in movements. Fish may be For stream resident fish optimal foraging habitat able to overwinter in marginal habitat if ground- usually consists of a series of riffles and pools with water springs are present (P. Davidson, pers. comm.). excellent cover in the form of undercut banks, log jams, boulders, and/or deep pools. Depths of pools Habitat have been positively correlated to the age of fish and large adults usually occupy the deepest pools with Structural stage the best cover (Griffith 1972). Young fish, in parti- Generally, structural stages 5–7 produce greater cular fry, rear and forage along the margins of amounts of large organic debris (LOD) which has an streams, in off-channel habitat, and in small tribu- important influence on stream channel development taries. Lower reaches of streams that are susceptible (Robison and Beschta 1990); sediment trapping and to warming in the summer are typically avoided or storage (Bragg et al. 2000); nutrient cycling (Bilby activity is curtailed as Westslope Cutthroat Trout are and Likens 1980); and fish habitat stucture (Bragg less tolerant than other salmonids to warm water et al. 2000). temperatures (i.e., >20°C) (McIntyre and Rieman

5 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 5 1995). Recent genetics evidence suggests that some Conservation and adults from the lower St Mary River move to the upper St Mary River, possibly in search of cooler Management temperatures (P. Corbett, pers. comm.). Status Young fish use a variety of habitats depending on the life history of the population they belong to The Westslope Cutthroat Trout is on the provincial (i.e., adfluvial, fluvial, or lake resident populations). Blue List in British Columbia. Its status in Canada For adfluvial and fluvial populations fry often use has not been determined but is currently under habitat where water velocities are very low (<1 cm/s) review. and water depths often do not exceed 20 cm (Ford Summary of ABI status in BC and adjacent et al. 1995). Gravel and cobble substrates are also jurisdictions (NatureServe Explorer 2002) important as cover for fry (Moore and Gregory 1988a; Ford et al. 1995). Age 1+ and 2+ tend to use BC ID MT OR WA Canada Global areas with higher velocities (maximum of 22 cm/s) and deeper water depths (Ford et al. 1995). Natural S3SE S2 S3 S3 S? N? G4T3 lake resident populations are rare in British Columbia although there are numerous stocked Trends mountain lakes. Young lake resident fish rear mainly Population trends in the littoral zone. In the United States and Alberta, populations have Overwintering declined significantly from historic levels (Mayhood Overwintering pools may contain large numbers of 1999; USFWS 1999). In the Missouri River Basin, mature adults throughout the fall and winter 90% of the 144 populations known to have at least (Westslope Fisheries 2003). These pools usually exist 90% genetic purity are at “high to very high” risk of in large mainstem streams (order 4 and up) and have becoming extinct (Shepard et al. 1997). In British features that provide deep water (>2 m deep), slower Columbia, populations declined significantly in the water velocity, and optimal cover. Large boulders, 1960s through to the mid-1980s due to liberal bedrock, or large organic debris are often associated fishing regulations, and increased angling pressure, with these pools. access, and habitat loss (B. Westover, pers. comm.). Since implementation of more restrictive fishing Staging regulations in the mid-1980s, populations have Prior to entering a spawning tributary in the spring increased substantially (B. Westover, pers. comm.). adults can congregate at the mouth of spawning The general trend for B.C. populations as a whole tributaries for several days or even weeks appears to be stable or increasing. However, many (Schmetterling 2001). Adults begin to display populations have some level of hybridization with spawning colours early in the spring (February Rainbow Trout. The number of genetically pure through May) and move to the mouths of tributary populations has declined in Alberta by as much as streams prior to spawning. Northcote and Hartman 95% from their former range (Mayhood 1999) and (1988) observed maturing males in April even by as much as 97.5% in parts of their range in the though no spawning was observed until mid-July in United States (McIntyre and Rieman 1995). The small tributaries to Kootenay Lake. The habitat of genetic status of populations in British Columbia staging areas has not been well defined. It likely has not been completely determined; however, it varies depending on local conditions but generally appears that pure populations are declining would consist of pool habitat with good cover. (Rubidge et al. 2002; P. Corbett, pers. comm.). Genetic studies in 1987 found one tributary stream to the Kootenay River had Westslope Cutthroat

6 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Trout/Rainbow Trout hybrids (Leary et al. 1987). A focusing may be at higher risk. Some habitat losses repeat sampling of the same streams in 1999 found are being offset by restoration efforts (e.g., Mark seven streams with hybrids present (P. Corbett, pers. Creek, Sand Creek). comm.; Rubidge et al. 2002). Current studies in British Columbia have looked at 20 streams in Threats southeastern British Columbia and found that only Population threats five have pure populations and 15 had a moderate to high risk of becoming introgressed populations due By far the biggest threat to the continued existence to presence of either hybrids or naturalized Rainbow of Westslope Cutthroat Trout is genetic introgression Trout populations (P. Corbett, pers. comm.). with Rainbow Trout (Allendorf and Leary 1988; Taylor and Stamford 2000). Stocking of Rainbow Rainbow trout have been stocked in several lakes and Trout in Westslope Cutthroat Trout habitat and the streams that flow into the Kootenay River since the subsequent naturalization of Rainbow Trout is the early 1900s. The Libby dam was completed on the leading cause of introgression between the two Kootenay River in 1972 forming the Koocanusa species (McIntyre and Rieman 1995; Haas 1998). Reservoir. For several years the United States Other threats include increased access; overfishing; attempted to establish Westslope Cutthroat in the predation by non-native species; and competition Reservoir with little success (B. Westover, pers. and displacement from non-native fish. Some comm.). Between 1986 and 1998 Gerrard Rainbow populations may be more susceptible to disturbance Trout were stocked in the Koocanusa Reservoir. This if they naturally occur over a limited range and/or in stocking history has no doubt been the cause of the small numbers (Allendorf and Leary 1988). hybridization between Westslope and Rainbow evident today. It is not known if the rate of hybrid- The vast increase in the number of roads in ization is increasing and if populations of Westslope previously unroaded watersheds is a major concern Cutthroat Trout in British Columbia will continue to because it is allowing anglers unprecedented access decline as they have in Alberta and the United States; to streams. Westslope Cutthroat Trout are par- however, the genetics work conducted to date and ticularly sensitive to angling pressure because they reports from local anglers suggest that hybridization are readily caught even by novice anglers. Poaching is likely increasing. can also increase if access to previously roadless areas is developed and the number of enforcement Habitat trends personnel is not also increased. Large amounts of Westslope Cutthroat Trout habitat Haas (1998) classified Westslope Cutthroat Trout a were lost between 1960 and 1981 which coincided species that requires “special forestry consideration” with a dramatic increase in the population of many because they exhibit the following life history and East Kootenay communities. For example, ecological characteristics that make them susceptible Cranbrook grew from approximately 5000 to over to forestry and other development activities: 15 000 during this time (B. Westover, pers. comm.). • often found in the headwaters and small streams, With an increase in human population, a variety of • most populations are stream resident, development activities dramatically increased, which • dependent on riparian and instream cover, contributed to an incremental loss of high quality • dependent on natural flow and stream Westslope Cutthroat Trout habitat throughout much hydrological features, of its range. In general, lake and large stream habitat • require clean, well-oxygenated, unembedded is more secure, although there continue to be some gravel substrate for spawning, cumulative impacts from forestry, hydroelectric, • repeat spawners, mining, agriculture, urban development, and indus- trial pollution (Haas 1998). Tributary streams at • sport species that is easily angled, and higher elevations where forestry operations are now • intolerant of high temperatures.

7 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 7 Habitat threats can degrade spawning and rearing habitat and cause direct injury to fish by: Forest harvesting, mining, agriculture, hydroelectric development, urban development, and livestock • embedding (infilling gravel substrate); grazing have all impacted Westslope Cutthroat • infilling pool and riffle habitat; habitat in the past and may continue to do so. These • clogging and abrading fish gills; threats influence fish habitat in the following general • increasing turbidity, impairing feeding ability; categories: elimination of habitat or restriction of and fish access; sedimentation and erosion; and altera- • smothering aquatic insects, reducing food tion or loss of required habitat characteristics. availability and lowering stream productivity (Weaver and Fraley 1991; DFO and MOE 1992; Elimination or restriction Anderson 1998; USFWS 1999).

The creation of dams and reservoirs in the Columbia Alteration of habitat characteristics basin has eliminated large amounts of low elevation stream reaches via complete inundation (Ford et al. During forest harvesting, grazing, mining, and urban 1995; McIntyre and Rieman 1995). Hydroelectric development, riparian vegetation is sometimes developments have also created barriers that in some removed or degraded. Loss of riparian vegetation can cases alter historic movement patterns (Ford et al. have adverse impacts on fish habitat because it can be 1995). At smaller scales forestry and urban develop- critical in the maintenance of many important ment can also impede fish movement if proper road habitat features required by Westslope Cutthroat building practices are not followed (DFO and MOE Trout. Riparian vegetation is important as it: 1992). Perched culverts, debris, channelization, and 1. provides short- and long-term recruitment of increased water velocities are a common source of LOD for the creation of optimal salmonid habitat such as pools and cover (DFO and MOE 1992); barriers to adfluvial, fluvial, and resident populations preventing populations from accessing key 2. provides shade which cools streams significantly more than streams without riparian vegetation habitats (Rieman and Apperson 1989; DFO and (Scruton et al. 1998; Maloney et al. 1999); MOE 1992; McIntyre and Rieman 1995). The 3. increases bank stability and maintains channel isolation and restriction of populations can com- morphology (Robison and Beschta 1990; DFO promise the gene flow within and between popula- and MOE 1992; Bragg et al. 1998, 2000); tions and negatively affect the long-term persistence 4. acts as a substrate for many terrestrial insects, of the species (Allendorf and Leary 1988; McIntyre which in turn are an important food source, and and Rieman 1995). Some streams in Alberta are provides organic matter (in the form of leaf estimated to have fewer than 30 adults in the litter) that supports the aquatic food chain population which may not be a sufficient minimum (Minshall 1967; DFO and MOE 1992; Wipfil viable population size (D. Mayhood, pers. comm.) 1997); and 5. intercepts runoff and acts as a filter for sediment Sedimentation and erosion and pollutants (DFO and MOE 1992). Forest harvesting, grazing, mining, and urban Global warming is also predicted to further reduce development can all contribute to increased Westslope Cutthroat Trout habitat by changing water sedimentation and nutrient loading through the temperatures thereby reducing the amount of low increased runoff, debris torrents, and slides elevation habitat suitable for adults (Kelehar and (Rieman and Apperson 1989; Dunnigan et al. 1998; Rahel 1992; Mullan et al. 1992; McIntyre and Huntington 1998; Oman 1998; Spencer and Schelske Rieman 1995). Increased water temperatures will 1998). Increased sedimentation and erosion (above also reduce the amount of cool water habitat for natural background levels) are undesirable as they rearing in the upper reaches of the watershed.

8 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Legal Protection and Habitat portions of the Kootenay River watershed within Conservation Kootenay National Park; tributaries to the upper and lower Kootenay River within Height of the Rockies, Westslope Cutthroat Trout in British Columbia are Elk Lakes, St Mary’s Alpine, West Arm, Valhalla, and protected under the provincial Wildlife Act, the Kokanee provincial parks; and tributaries to the provincial Fish Protection Act, and the federal upper Columbia River within the Purcell Wilderness Fisheries Act. The Wildlife Act enables provincial Area. However, many of these areas either have authorities to license anglers and angling guides, and limited amounts of quality habitat and/or have been to supply scientific fish collection permits, and the subjected to many years of fish stocking with other Fish Protection Act provides the legislative authority stocks of Westslope Cutthroat Trout, Rainbow Trout, for water managers to consider impacts on fish and and/or Brook Trout (Salvelinus fontinalis), which fish habitats before approving new water licences or may have compromised the genetics of the native amendments to existing licences, or issuing approv- Westslope Cutthroat Trout populations, and/or acted als for works in and about streams. However, the as direct competitors of the native populations. Fish Protection Act cannot be used to supercede activities authorized under the provincial Forest Act, Provisions enabled under the Forest Practices Code or where the Forest Practices Code or its successor, (FPC) or its successor, the Forest and Range Practices the Forest and Range Practices Act, applies (see Act (FRPA), that may help maintain habitat for this Section 7(7), Fish Protection Act). species include: ungulate winter range areas; old growth management areas; riparian management The federal Fisheries Act delegates authority to the areas; community watersheds; coarse woody debris Province to establish and enforce fishing regulations retention, visual quality objectives; and the wildlife under the British Columbia Sport Fishing Regula- habitat feature designation. All of these, except tions. These Regulations incorporate a variety of community watersheds, have the ability to protect measures to protect fish stocks, including stream and relatively small portions of streamside vegetation lake closures, catch and release fisheries, size and (i.e., a few hundred hectares) along a stream; catch limits, and gear restrictions (e.g., large portions community watersheds have the potential to protect of the Elk and St Mary rivers are designated “catch an entire population of a stream resident form. and release” zones for most of the fishing season). However, one potential problem with these provi- In addition, Section 35(1) of the federal Fisheries Act sions is that the current Riparian Management Area prohibits activities that may result “in the harmful (RMA) guidelines do not require retention of a alteration, disruption, or destruction of fish habitat.” reserve zone on S4 streams (small, fish-bearing; Similarly, Section 36(3) of the Act prohibits the <1.5 m wide), only a 30 m management zone (MOF deposition of a “deleterious substance of any type” and MOELP 1995). This could put many of the into waters frequented by fish. remaining pure populations of Westslope Cutthroat Also of note is the fish habitat policy of the federal Trout at risk because most pure populations are now Department of Fisheries and Oceans, which includes found in smaller headwater tributary streams above a goal of “… no net loss of the productive capacity natural or man-made barriers (McIntyre and of fish habitat”, which is designed to maintain the Rieman 1995; Mayhood 1999; P. Corbett, pers. maximum natural fisheries capacity of streams comm.). It has not been fully determined how (Chilibeck et al. 1992). important S4 streams are to resident Westslope Cutthroat Trout populations but they likely provide The provincial system of parks and protected areas, valuable rearing habitat for fry and possibly 1+ and and the federal system of parks, provide some level 2+ age classes, and potentially provide valuable of protection for certain populations, or portions of spawning habitat. Under the proper conditions populations, of Westslope Cutthroat Trout. Streams (i.e., groundwater springs or upwelling areas), S4 within these protected areas include: the upper

9 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 9 streams may even provide some overwintering the extensive existing access. Consider the habitat. following access management recommendations: • When planning new road development keep Identified Wildlife Provisions roads ≥1 km from mainstem streams (order 4 and greater). Sustainable resource management and • In previously developed drainages, assess the planning recommendations percentage of the streamside paralleled by To date there are few medium to large streams (order roads and the number of access points 4 or higher) with confirmed pure populations of provided by crossings, spur roads, etc. Westslope Cutthroat Trout in the Kootenay River • If <25% of the mainstem stream is >1 km watershed (P. Corbett, pers. comm.). These streams beyond a known access point, consider are important and can act as a source of native, non- removing some access points. hybridized Westslope Cutthroat Trout that could be Maximize connectivity of native, non-hybridized used to re-establish populations where they have populations. Movement of individuals (gene flow) between subpopulations in the same been extirpated. To protect native populations of watershed may be an important way for popula- Westslope Cutthroat Trout consider the following tions to rebound after natural catastrophic events recommendations: and limiting this movement could decrease the Because larger streams with intact populations of likelihood of local populations persisting over Westslope Cutthroat Trout are rare throughout time (Hilderbrand and Kershner 2000; their range and are extremely valuable, these Schmetterling 2001). Therefore, obstructions streams (order 4 or greater) should be recognized should not be created by in-stream structures as sensitive streams and designated as “regionally such as culverts and bridges, and construction of significant.” dams and weirs should be strongly discouraged Because the most serious threat to the native, in Westslope Cutthroat Trout habitat. non-hybridized populations is the introduction Limit competition from non-native species that of non-native species to the watershed (i.e., other can often displace Westslope Cutthroat Trout strains of Westslope Cutthroat Trout or other from preferred habitat. species especially Rainbow Trout), current In sub-basins where Westslope Cutthroat Trout natural and/or human-made barriers should be spawning or rearing are known to occur or where maintained in the short-term until the threats they likely occur and forest activities are planned from non-native invasions are further assessed. in the next 5 years, any of the following criteria Local managers should determine the appro- are recommended as supplementary triggers for priate size of the riparian zone on all order 3 and the watershed assessment procedure (WAP): smaller streams with pure Westslope Cutthroat • more than 10% of the watershed has been Trout populations based on the potential for logged in the 20 years prior to the start of the impacts on the stream due to development. Low proposed development plan, or will be logged elevation streams susceptible to warming in the in the 25 years prior to the end of the summer and any stream with naturally unstable proposed development plan. banks or temperature sensitive streams should • sub-basins where a significant number of have minimum riparian management reserve mass wasting events have occurred (i.e., more zone of 20 m. than one landslide/km2 and more than two Limit access to undisturbed Westslope Cutthroat events reaching the mainstem); Trout populations. Westslope Cutthroat Trout are • sub-basins where there is either high road susceptible to overfishing; therefore, future road density (i.e., >150 m of road/km2) or high building in sub-basins with Westslope Cutthroat stream density (i.e., >1 km of channel/km2) Trout populations should be located in upslope or a significant number of stream crossings positions to avoid providing easy access for (i.e., >0.6/km2); and fishing. Maintenance of restrictive fishing regulations will help to limit some impacts from • evidence of significant stream channel stability problems.

10 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 If the WAP determines that the watershed is feature to be protected, or inclusion of upstream sensitive to disturbance (i.e., a rating of medium reaches (S5, S6) necessary to achieve goals. Spawning or high in the hazard category), Westslope and rearing areas could be larger if adult fish spawn Cutthroat Trout populations are at risk, in which or rear over several kilometres (1–5 km) of stream case, the temporal and spatial layout of cutblocks, hydrologic green-up, and recovery reach (i.e., Elk River, St Mary River). standards, and road layout and design must be Design considered. Recent genetic studies have shown that there is a The WHA should include the entire feature of large degree of genetic divergence between interest (e.g., spawning area) plus a 20 m core area populations throughout their range (Taylor et al. and 20–30 m management zone determined from 2003). In particular, populations above and stream size. streams in close proximity can have genetically unique populations. These studies suggest that Overwintering and staging pools have been iden- multiple populations within a region need to be tified in the Elk and St. Mary rivers (Westslope conserved to maintain the full spectrum of Fisheries 2003). Spawning habitat is typically found cutthroat genetic resources. in smaller, low-gradient stream reaches that have abundant gravel substrate, shallow riffles, and good Wildlife habitat area cover. Rearing habitat typically is found in very small Goal tributaries and fisheries sensitive zones such as Maintain overwintering, staging, spawning, and beaver ponds and back channels. rearing habitat of native, non-hybridized popu- General wildlife measures lations not addressed through strategic or landscape level planning. WHAs should be established across Goals the landscape to best protect a variety of subpopu- 1. Prevent disturbance of Westslope Cutthroat lations and life stages with particular emphasis on Trout particularly during spawning and overwintering periods when adults tend to be those populations with the least risk of genetic congregated. introgression. 2. Maintain sufficient riparian vegetation to Feature maintain stream temperatures within the natural range of variability and provide nutrient input, The priority for WHA establishment is known cover, stream bank stability, and shade. spawning, rearing, overwintering, and staging pools 3. Limit access to populations that may be sensitive for populations of native, non-hybridized Westslope to overharvest. Cutthroat Trout that occur in small streams (S4). 4. Maintain critical instream habitats including Priority for WHAs should be for populations that spawning and rearing habitat. are naturally isolated above barriers that have 5. Maintain water quality sufficient to sustain fish, evolved unique morphological and presumably fish habitats, and aquatic ecosystems. genetic characteristics (e.g., Akolkolex River, Bull 6. Maintain sufficient water to sustain fish, fish River, Kirkup Creek, Fording River). Select areas habitat and aquatic ecosystems through all life where there appear to be higher than average stages. concentrations of fish (>20% of the adult popu- 7. Maintain natural stream morphology and lation of a run) and/or where the habitat appears to complexity. be susceptible to impacts from human activities. 8. Maintain structural integrity of riparian plant community, stream banks, and channel. Size 9. Maintain processes that lead to the creation of a Generally between 5 and 20 ha; however, the size of wide variety of aquatic habitats similar to the the WHA will vary depending on the stream system, local reference conditions.

11 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 11 Measures Information Needs Access 1. Determine status of population, specifically how • Limit access through road closures, deactivation, many pure populations exist. or seasonal closures during critical times 2. Determine the risk of extinction of non-pure (e.g., overwintering and staging – 30 September populations and rank them based on potential to to 15 April; spawning – 15 April to 15 July; rehabilitate. rearing – 15 July to 31 March). Consult MWLAP 3. Investigate life history of adfluvial, fluvial, and for site-specific times. lake resident Westslope Cutthroat Trout • Do not place roads or crossing structures within populations. WHA. Cross References Harvesting and silviculture • Do not harvest or salvage in the core area. Bull Trout, Rocky Mountain Tailed Frog • When conducting silvicultural practices, mini- mize access developments as per above access References Cited measure and ensure natural processes for stream Alger, D. and D. Donald. 1984. Limnological studies in maintenance are not adversely affected. Consult Kootenay National Park. Part two: the streams. Can. MWLAP for site-specific recommendations. Wildl. Serv., Edmonton, Alta. Pesticides Allendorf, F.W. and R.F. Leary. 1988. Conservation and distribution of genetic variation in a polytypic • Do not use pesticides. species, the cutthroat trout. Conserv. Biol. 2:170–184. Range Anderson, P. 1998. Sediment generation from forestry • Control livestock use of riparian areas. Where operations and associated effects on aquatic assessments have determined that range practices ecosystems. In Proc. Forest-Fish Conf.: land have degraded or altered riparian and aquatic management practices affecting aquatic ecosystems, habitat, change management practices, and/or May 1–4, 1996. M. Brewin and D. Monita (editors). remediate to achieve properly functioning Can. For. Serv., Edmonton, Alta., NOR-X-356, condition. Ensure livestock use does not impede pp. 491–508. natural recovery or other remediation efforts. Baxter, J. and J. Hagen. 2003. Population size, • Fencing could be recommended by the statutory reproductive biology, and habitat use of westslope decision maker. cutthroat (Onchorhynchus clarki lewisi) in the • Plan livestock grazing to maintain desired plant Wigwam River watershed. Rep. prepared for B.C. community, stubble height, and browse Min. Water, Land and Air Protection, Nelson, B.C. utilization. Behnke, R.J. 1992. Native trout of western North America. Am. Fish. Soc. Monogr. 6. Recreation Bilby, R. and G. Likens. 1980. Importance of organic • Do not develop recreational sites or trails. debris dams in the structure and function of stream ecosystems. Ecology 61:1107–1113. Additional Management Bjornn, T. and J. Mallet. 1964. Movements of planted Considerations and wild trout in an Idaho river system. Trans. Am. Fish. Soc. 93:70–76. Maintain riparian reserves on all S4 streams with or Bragg, D., J. Kershner, and D. Roberts. 1998. Application suspected to have pure Westslope Cutthroat Trout of a coarse woody debris recruitment model to populations or S5 and S6 streams that are tributary investigate the impacts of riparian forest harvest and to streams with Westslope Cutthroat Trout, where stream clearing. In Proc. Forest-Fish Conf.: land management practices affecting aquatic ecosystems, local managers deem it necessary to protect natural May 1–4, 1996. M. Brewin and D. Monita (editors). stream processes and limit erosion and sedimen- Can. For. Serv., Edmonton, Alta., NOR-X-356, pp. tation caused by forestry practices. 509–514.

12 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 ______. 2000. Modeling large woody debris Griffith, J. 1972. Comparative behaviour and habitat recruitment for small streams of Central Rocky utilization of brook trout (Salvelinus fontinalis) and Mountains. U.S. Dep. Agric. For. Serv., Rocky Mtn. cutthroat trout (Salmo clarki) in small streams in Res. Stn. Gen. Tech. Rep. RM-55. northern Idaho. J. Fish Res. Board Can. 29:265–273. Brown, C. 1971. Fishes of Montana. Big Sky Books, Haas, G. 1998. Indigenous fish species potentially at risk Bozeman, Mont. in BC, with recommendations and prioritizations Brown, R. 1999. Fall and early winter movements of for conservation, forestry/resource use, inventory cutthroat trout (Oncorhynchus clarki) in relation to and research. B.C. Min. Fish., Res. and Dev. Section, water temperature and ice conditions in Dutch Univ. B.C., Vancouver, B.C. Fish. Manage. Rep. No. Creek, Alberta. Environ. Biol. Fishes 55(4):359–368. 105. Brown, R.S. and W.C. Mackay. 1995. Fall and winter Henderson, R., J. Kershner, and C. Toline. 2000. Timing movements of and habitat use by cutthroat trout in and location of spawning by nonnative wild the Ram River, Alberta. Trans. Am. Fish. Soc. rainbow trout and native cutthroat trout in the 124:873–885. South Fork of the Snake River, Idaho, with implications for hybridization. N. Am. J. Fish. Chilibeck, B., G. Chislett, and G. Norris. 1992. Land Manage. 20:584–596. development guidelines for the protection of aquatic habitat. Dep. Fish. Oceans, Pacific Reg., and Hilderbrand, R. and J. Kershner. 2000. Movement B.C. Min. Environ., Integrated Habitat Div., patterns of stream resident cutthroat trout in Beaver Victoria, B.C. Creek, Idaho-Utah. Trans. Am. Fish. Soc. 129:1160– 1170. Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 2002. Canadian Species at Huntington, C. 1998. Streams and salmonid Risk. www.speciesatrisk.gc.ca assemblages within roaded and unroaded landscapes in Clearwater River sub-basin, Idaho. In Corbett, P. 2001. Perry Creek spawning enumeration: Proc. Forest-Fish Conf.: land management practices 2001. Draft report prepared for Global Forest, affecting aquatic ecosystems, May 1–4, 1996. M. Vancouver, B.C. Brewin and D. Monita (editors). Can. For. Serv., Corbett, P., E. Taylor, and E. Rubidge. 2001. Genetic Edmonton, Alta., NOR-X-356, pp. 413–428. assessment of Westslope Cutthroat Trout Kelehar, C. and F. Rahel. 1992. Potential effect of (Oncorhynchus clarki lewisi) in the St Mary River of climatic warming on salmonid distributions in SE British Columbia: 2000. Prepared for Columbia- Wyoming. West. Div. Am. Fish. Soc. Ann. Meet., July Kootenay Fisheries Renewal Partnership, 13–16, 1992, Fort Collins, Colo. Cranbrook, B.C. Leary, R., F. Allendorf, and K. Knudsen. 1987. Genetic Downs, C., R. White, and B. Shepard. 1997. Age at divergence among populations of westslope sexual maturity, sex ratio, fecundity, and longevity cutthroat trout in the upper Kootenay River of isolated headwater populations of Westslope drainage, British Columbia. Population Genetic Lab Cutthroat Trout. N. Am. J. Fish. Manage. 17:85–92. Rep. 87/1. Univ. Mont., Dep. Zool., Missoula, Mont. Dunnigan, J.L., D.H.Bennett, B.E. Rieman. 1998. Effects Liknes, G. and P. Graham. 1988. Westslope cutthroat of forest management on westslope cutthroat trout trout in Montana: life history, status, and distribution and abundance in the Coeur d’Alene management. Am. Fish. Soc. Symp. 4:53–60. River system, Idaho, USA. In Proc. Forest-Fish Conf.: land management practices affecting aquatic Lukens, J. 1978. Abundance movements and age ecosystems, May 1–4, 1996. M. Brewin and D. structure of adfluvial Westslope Cutthroat Trout in Monita (editors). Can. For. Serv., Edmonton, Alta., Wolf Creek drainage, Idaho. M.Sc. thesis. Univ. NOR-X 356. pp. 471–476. Idaho, Moscow, Idaho. Ford, B., P. Higgins, A. Lewis, K. Cooper, T. Watson, C. McIntyre, J.D. and B.E. Rieman. 1995. Westslope Gee, G. Ennis, and R. Sweeting. 1995. Westslope cutthroat trout. In Conservation assessment for cutthroat trout. In Literature reviews of the life inland cutthroat trout. M. Young (editor). Rocky history, habitat requirements and mitigation/ Mt. For. and Range Exp. Stn., Gen. Tech. Rep. RM- compensation strategies for selected fish species in GTR-256, pp. 1–15. the Peace, Liard and Columbia River Drainages of British Columbia. Dep. Fish. Oceans, pp. 1–22.

13 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 13 McIntyre, J.D. and B.E. Rieman. 1995. Westslope Oman, D. 1998. The recovery of degraded riparian cutthroat trout. In Conservation assessment for systems with improved livestock management. In inland cutthroat trout. M. Young (editor). Rocky Proc. Forest-Fish Conf.: land management practices Mt. For. and Range Exp. Stn., Gen. Tech. Rep. RM- affecting aquatic ecosystems, May 1–4, 1996. M. GTR-256, pp. 1–15. Brewin and D. Monita (editors). Can. For. Serv., McPhail, D. and R. Carveth. 1992. A foundation for Edmonton, Alta., NOR-X-356, pp. 139–148. conservation: the nature and origin of the Rieman, B. and K. Apperson. 1989. Status and analysis freshwater fish fauna of British Columbia. Univ. of salmonid fisheries: westslope cutthroat trout B.C., Dep. Zool., Fish Mus., Vancouver, B.C. synopsis and analysis of fishery information. Idaho _____. 1993. Field key to the freshwater fishes of British Dep. Fish and Game, Boise, Idaho. Project F-73-R- Columbia. Univ. B.C., Vancouver, B.C. 11. Maloney, S., A. Tiedmann, D. Higgins, T. Quigley, and Robison, E. and R. Beschta. 1990. Characteristics of D. Marx. 1999. Influence of stream characteristics coarse woody debris for several coastal streams of and grazing intensity on stream temperatures in southeast Alaska, USA. Can. J. Fish. Aquat. Sci. Eastern Oregon. U.S. Dep. Agric. For. Serv., PNW- 47:1684–1693. GTR-459. Roscoe, J.W. 1974. Systematics of the westslope Mayhood, D. 1999. Provisional evaluation of the status cutthroat trout. M.Sc. thesis. Colo. State Univ., Fort of westslope cutthroat trout in Canada. In Proc. Collins, Colo. Conf. on the Biology and Management of Species Rubidge, R., P. Corbett, and E. Taylor. [2002]. A and Habitat at Risk, Kamloops, B.C., Feb. 15–19, molecular analysis of hybridization between native 1999. L.M. Darling (editor). B.C. Environ., Lands westslope cutthroat trout (Oncorhynchus clarki and Parks, Victoria, B.C. and Univ. Coll. Cariboo, lewisi) and introduced rainbow trout (O. mykiss) in Kamloops, B.C., pp. 579–586. southeastern British Columbia, Canada. Can. J. Fish. Minshall, G. 1967. Role of allochthonous detritus in the Aquat. Sci. 59. In press. trophic structure of a woodland springbrook Schmetterling, D. 2001. Seasonal movements of fluvial community. Ecology 48:139–149. westslope cutthroat trout in the Blackfoot drainage, Moore, K. and S. Gregory. 1988a. Response of young- Montana. N. Am. J. Fish. Manage. 21:507–520. of-year cutthroat trout to manipulation of habitat Scruton, D., K. Clarke, and L. Cole. 1998. Water structure in a small stream. Trans. Am. Fish. Soc. temperature dynamics in small forested headwater 117:162–170. streams of Newfoundland, Canada: Quantification ______. 1988b. Summer habitat utilization and ecology of thermal brook trout habitat to address initial of cutthroat trout fry (Salmo clarki) in Cascade effects of forest harvesting. In Proc. Forest-Fish Mountain streams. Can. J. Fish. Aquat. Sci. 45:1921– Conf.: land management practices affecting aquatic 1930. ecosystems, May 1–4, 1996. M. Brewin and D. Monita (editors). Can. For. Serv., Edmonton, Alta., Mullan, J., K. Williams, G. Rhodus, T. Hilliman, and J. NOR-X-356, pp. 325–336. McIntyre. 1992. Production and habitat of salmonids in mid-Columbia River tributary Shepard, B., K. Pratt, and P. Graham. 1984. Life histories streams. U.S. Dept. Interior U.S. Fish Wildl. Serv., of westslope cutthroat and bull trout in the Upper Monogr. 1. 60 p. Flathead River basin, Montana. Environ. Prot. Agency, Reg. VIII, Water Div., Denver, Colo. 85 p. NatureServe Explorer. 2002. An online encyclopedia of life [Web application]. Version 1.6. Arlington, Va. Shepard, B., B. Sanborn, L. Ulmer, and D. Lee. 1997. Available from: http://www.natureserve.org/ Status and risk of extinction for westslope cutthroat explorer trout in the upper Missouri River basin, Montana. N. Am. J. Fish. Manage. 17:1158–1172. Northcote, T. and G. Hartman. 1988. The biology and significance of stream trout populations (Salmo Spencer, C. and C.L. Schelske. 1998. Impacts of timber spp.) living above and below waterfalls. Pol. Arch. harvest on sediment deposition in surface waters in Hydrobiol. 35:409–442. northwest Montana over the last 150 years: a paleolimnological study. In Proc. Forest-Fish Conf.: land management practices affecting aquatic ecosystems, May 1–4, 1996. M. Brewin and D. Monita (editors). Can. For. Serv., Edmonton, Alta., NOR-X-356, pp. 187–202.

14 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Taylor, E.B., M.D. Stamford, and J.S. Baxter. 2003. Personal Communications Population subdivision in westslope cutthroat trout (Oncorynchus clarki lewisi) at the northern Baxter, J. 2002. Baxter Environmental Services, Nelson, periphery of its range: evolutionary inferences and B.C. conservation implications. Molecular Ecol. Corbett, P. 2002. Mirkwood Ecological Consultants Ltd, 12:2609–2622. Winlaw, B.C. Taylor, R. and M.D. Stamford. 2000. A preliminary Davidson, P. 2002. Min. Water, Land, and Air assessment of hybridization between native Protection, Cranbrook, B.C. westslope cutthroat trout (Oncorhynchus clarki Mayhood, D. 2002. Freshwater Research Limited, lewisi) and introduced rainbow trout (O. mykiss) in Calgary, Alta. selected East Kootenay watersheds. Prepared for Norris, J.G. 2003. Min. Water, Land and Air Protection, Mirkwood Ecological Consultants Ltd., Winlaw, Victoria, B.C. B.C. 17 p. Prince, A. 2002. Westslope Fisheries, Cranbrook, B.C. Trotter, P.C. 1987. Cutthroat, native trout of the west. Colo. Assoc. Univ. Press. Boulder, Colo. 219 p. Stelfox, J. 2002. Sustainable Resource Development, Fish and Wildl. Br., Calgary, Alta. U.S. Fish and Wildlife Service (USFSW). 1999. Status review for westslope cutthroat trout in the United Westover, B. 2002. Min. Water, Land, and Air States. U.S. Dep. Inter. Reg. 1 and 6, Portland, Oreg. Protection, Cranbrook, B.C. and Denver, Colo. Weaver, T. and J. Fraley. 1991.Fisheries habitat and fish populations. Final report for the Flathead Basin forest practices water quality and fisheries cooperative program. Flathead Basin Commission, Kalispell, Mont. Westslope Fisheries. 2003. Elk River westslope cutthroat trout radio-telemetry study: 2000–2002. Report prepared for Columbia-Kootenay Fisheries Renewal Partnership, Cranbrook, B.C. Wipfli, M. 1997. Terrestrial invertebrates as salmonid prey and nitrogen sources: contrasting old-growth and young-growth riparian forests in southeastern Alaska, USA. Can. J. Fish. Aquat. Sci. 54:1259–1269.

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