Arctic Grayling

grayling2Emily Rens & Patrick Byorth
Montana Fish, Wildlife, & Parks
Dillon, MT 59725

January 2010

[headings title="Outline" size="50" level="3"]

Legal Status

Arctic grayling Thymallus arcticus are native to northern North America. Among the contiguous 48 states, native populations of grayling were once found in both Montana and Michigan. In 1936, the Michigan population went extinct due to habitat degradation and over fishing. In Montana, both life forms of Arctic grayling exist, lake dwelling (lacustrine or adfluvial) and river dwelling (fluvial). Currently, adfluvial Arctic grayling are common in lakes across the western half of Montana. Historically, fluvial Arctic graying were widespread throughout the Missouri River drainage upstream of Great Falls. They now are reduced to a single, native population in the Big Hole River, in southwest Montana (Figure 1.)

Population Status

In the mid-1980s, the fluvial Arctic grayling population in the Big Hole River declined. In response, Montana Fish, Wildlife and Parks (FWP) and partners initiated the Arctic Grayling Recovery Program (AGRP). The program’s goals are to address factors limiting the Big Hole River population, monitor and enhance essential habitats, monitor abundance and population demographics, restore additional Arctic grayling populations within their native range, develop relationships that promote conservation actions, and inform the public of the status and conservation efforts for Arctic grayling. Monitoring and research results have been reported annually since 1991 (Byorth 1991; 1993; 1994; 1995a; 1997; Magee and Byorth 1995; Byorth and Magee 1996; Magee and Byorth 1998; Magee 1999; Magee and Opitz 2000; Magee 2002; Magee and Lamothe 2003; Magee et al. 2005; Magee et al. 2006; Rens and Magee 2007).

Presently, fluvial Arctic grayling distribution is greatly reduced from historical distribution. Research has identified limiting factors, and management strategies have been developed to protect and enhance fluvial Arctic grayling and their habitat. Kaya (1991) and Kaya and Jeanes (1995) studied rheotactic behavior in fluvial and adfluvial stocks of Arctic grayling and concluded that the fluvial life history form of Arctic grayling appears to be uniquely distinguished from the adfluvial life history form. Therefore, for conservation purposes all life history forms need to be conserved, because attempting to re-found one life history form from another may not be possible.
graylingdistribution
Figure 1. Historic distribution (gold line) and current distribution (blue line) of fluvial Arctic grayling in Montana.

Legal Status

At the end of the 19th century, fluvial Arctic grayling were distributed throughout the upper Missouri drainage above Great Falls (Vincent 1962). During the 20th century, the range of fluvial Arctic grayling was reduced and the only remaining population exists in the Big Hole River of southwest Montana; the fish now occurs in less than 5% of its native range (Figure 1; Kaya 1992a). Vincent (1962) attributed the decline of fluvial Arctic grayling to four factors: habitat degradation, introduction of non-native salmonids, climatic change, and exploitation by anglers.

Fluvial Arctic grayling in Montana are designated as a “Species of Concern” by FWP and the Montana Natural Heritage Program, a “Species of Special Concern” by the Montana Chapter of the American Fisheries Society, and a fish of “Special Concern” by the Endangered Species Committee of the American Fisheries Society (Holton 1980; Clark 1989; Williams et al. 1989). The United States Forest Service (USFS) and the Bureau of Land Management (BLM) classify fluvial Arctic grayling as a sensitive species. Montana Arctic grayling were designated as a category 2 species by the USFWS in 1982 (USFWS 1982, 47 FR 58454). In October 1991, the United States Fish and Wildlife Service (USFWS) received a petition to list fluvial Arctic grayling in Montana throughout its historic range under the Endangered Species Act (ESA, USFWS 1991). The USFWS 1994 finding classified fluvial grayling in Montana as a Category 1 species, which indicates that there was enough information on file to support a proposal to list the Arctic grayling as threatened or endangered. In March 2004, the USFWS elevated Arctic grayling in listing priority for a Distinct Population Segment (DPS) from a level 9 to a level 3 (USFWS 1994, 69 FR24881). This is the highest priority level given to a DPS. The priority level was elevated in 2004 because: 1) the distribution of fluvial Arctic grayling was less than 5% of its historic range; and, 2) recent population surveys suggested a decline in the Big Hole River population. In May 2003, a complaint was filed in U.S. District court challenging the “warranted but precluded” determination. In July 2004 the complaint was amended and challenged the failure to emergency list fluvial Arctic grayling (USFWS 1994). The litigation was settled in August 2005. In the settlement, the USFWS agreed to make a final determination of whether fluvial Arctic grayling population warranted listing as threatened or endangered by April 16, 2007. On April 24, 2007 the USFWS announced their revised 12-month finding stating that fluvial Arctic grayling of the upper Missouri River did not constitute a species, subspecies, or DPS under the ESA (USFWS 2007, 72 FR 20305) The petition to list fluvial Arctic grayling was therefore not warranted, and fluvial Arctic grayling have subsequently been withdrawn from the candidate list. In November 2007, a complaint was filed that challenged the revised finding. The USFWS settled with the plaintiffs and agreed to initiate a new status review for Arctic grayling of the upper Missouri River system. The review will consider various DPS designations that include different life histories in the upper Missouri River system (USFWS 74 FR 55525).

Abundance, Life History and Ecology

The fluvial Arctic grayling population of the upper Big Hole River is monitored annually by FWP to document population abundance, recruitment, age-class strength, and distribution. Fall population surveys in the upper Big Hole River and tributaries provide an index of fluvial Arctic grayling abundance and recruitment.

The upper Big Hole River grayling are found from Melrose, MT, upstream to Jackson, MT. Highest densities occur just upstream from the town of Wisdom, MT, downstream to Dickie Bridge (Figure 2). Spawning occurs upstream from the Mudd Creek Bridge in the main stem and several tributaries from Deep Creek upstream to Big Lake Creek (Magee and Lamothe 2003). Fluvial Arctic grayling rear in the vicinity of where they hatch; thus, mainstem and tributary reaches in this area provide the majority of rearing habitat.

Fluvial Arctic grayling grow quickly in the Big Hole River, reaching maturity by age 3. Fluvial Arctic grayling rarely live beyond 5 years in the Big Hole River. In contrast, fluvial Arctic grayling in Alaska mature from age 4 to 8 and commonly live to 12 years (Armstrong 1986). Fast growth rates and a short life span result in domination of spawning by age 3 and 4 fish. Thus, poor spawning success in a given year may substantially affect recruitment to the population for years.

bigholemap
Figure 2. Map of the Upper Big Hole River.

Threats

Factors potentially threatening persistence of fluvial Arctic grayling in the Big Hole River include water quality and quantity, competition with introduced species, predation, habitat degradation, and negative effects of angling. Water quantity issues include drought, irrigation withdrawals, and recruitment limitation due to sudden runoff events.

Sudden increases in stream flows during hatching and emergence of larval Arctic grayling may decrease survival and limit recruitment in the Big Hole River (Shepard and Oswald 1989). Similar detrimental effects of high flows during swim-up on Arctic grayling recruitment have been observed in the Chena River, Alaska (Clark 1992). It has been hypothesized that extreme flood flows negatively affected Arctic grayling recruitment in the Big Hole River during 1984 and 1985 (R. A. Oswald, FWP, personal communication). Conversely, extreme low flows during severe drought decrease survival of older Arctic grayling due to high water temperatures, increased susceptibility to predation, and diminished habitat volume. Diversion of water for agriculture in the Big Hole Valley has exacerbated persistent drought. All salmonids in the upper Big Hole River declined in abundance during the 1988 drought (Byorth 1993). During drought years, water temperatures have frequently surpassed the lethal limits for Arctic grayling reported by Lohr et al. (1996).

Several introduced salmonids such as brook trout Salvelinus fontinalis, rainbow trout Oncorhynchus mykiss, and brown trout Salmo trutta, also occur in the Big Hole River. Brook trout are found throughout the upper Big Hole River in both the main stem and tributaries. Historically, rainbow trout and brown trout abundances were higher downstream from Dickie Bridge, where fluvial Arctic grayling are at lower densities. However, the abundance of brown trout in upstream sections of the Big Hole River (upstream from Mudd Creek Bridge) is increasing, potentially due to increased temperatures from drought conditions, habitat alteration, and climatic change.

The distribution of fluvial Arctic grayling in the Big Hole River basin suggests they are displaced by non-native brown and rainbow trout; however, the mechanisms are unknown. Hypothetically, rainbow trout and brown trout may compete directly for food or habitat or prey on Arctic grayling (Kaya 1992a), or habitat and climatic changes may be benefiting non-native fishes while negatively affecting grayling. Studies indicate overlap in microhabitat preferences between Arctic grayling and rainbow trout (Magee and Byorth 1995). Brook trout and Arctic grayling are sympatric in the upper Big Hole basin, but appear to segregate according to microhabitat preferences (Skaar 1989; Magee and Byorth 1994; Magee and Byorth 1995).

Historically, angling may have negatively affected fluvial Arctic grayling populations in Michigan and Montana (Vincent 1962). Arctic grayling are easily caught by anglers and are susceptible to over-harvest. Recent research suggests that catch-and-release-only regulations enacted in 1988 in the Big Hole River adequately protect the Arctic grayling population from over-exploitation (Byorth 1993, FWP unpublished data).

Another factor potentially limiting grayling in the Big Hole River is habitat degradation. Degradation of riparian vegetation and stream banks through livestock use, mass willow removal, and dewatering the river for agricultural uses have negatively influenced fish habitat. Elevated levels of fine sediments, increased mid-summer water temperatures, and loss of suitable habitat volume have degraded Arctic grayling habitat in the Big Hole River. A study conducted by OEA Research, Inc (1995) indicated that fluvial Arctic grayling abundance was associated with high quality pools, which in turn were positively correlated (R2=0.88 P=0.05) to over-hanging vegetation (Lamothe and Magee 2004).

Management

In 1995, the Fluvial Arctic Grayling Workgroup (FGW) developed a restoration plan to conserve fluvial Arctic grayling in Montana (FGW 1995). A primary objective was to develop a brood stock from wild Big Hole River Arctic grayling to preserve their genetic identity. Gametes were collected from spawning Arctic grayling in the Big Hole River between 1988 and 1992, until a sufficient founding population was represented (Leary 1991). Progeny of the brood stock with genetic diversity representative to the Big Hole River wild stock have been available since 1995. Brood populations are located at two Montana lakes and the Yellowstone River Trout Hatchery, in Big Timber, Montana.

Another objective is to expand the range of fluvial Arctic grayling beyond the Big Hole River basin. Kaya (1992b) identified streams suitable for reintroductions of fluvial grayling. Gametes are collected annually from brood stocks to produce Arctic grayling fry using Remote Site Incubators (RSIs), or are raised to yearlings in a hatchery and planted at reintroduction sites. Experimental reintroductions have occurred in Cougar Creek and in the Firehole and Gibbons rivers in Yellowstone National Park, and the West and East Gallatin rivers. Intensive stocking efforts have taken place in the Ruby River (1997–2005), the Missouri River headwaters (2000–2006), lower Beaverhead River (1999-2001), and the North Fork of the Sun River (1999-2001). Stocked fluvial Arctic grayling have had high mortality rates but have reproduced in both the Ruby and the Sun River systems. Starting in 2003, RSIs have been used as an alternative, or in addition to stocking, in attempt to create self-sustaining populations in the Ruby River and the Sun River. Remote site incubators are an effective way to hatch fluvial Arctic grayling fry because the fry are subject to the unique selective mechanisms of each stream. In addition, they may imprint Arctic grayling to suitable spawning and rearing habitat. Survival of fluvial Arctic grayling produced from RSIs has improved compared to stocked fish, with numerous Arctic grayling surviving to age-1 and older. The ultimate goal of these efforts is for Arctic grayling to return to natal tributaries to successfully spawn.

Candidate Conservation Agreements with Assurances

The remaining fluvial Arctic grayling in Montana inhabit the Big Hole River Basin, which is primarily private land. In an effort to secure and enhance this population, FWP and its partners are developing conservation plans for private landowners through the Candidate Conservation Agreements with Assurances (CCAA) program. The goal of the CCAA program is to enhance the population of Arctic grayling in the upper Big Hole River by improving streamflow, protecting and enhancing stream habitat and riparian areas, increasing fish passage, and eliminating entrainment of fish in irrigation ditches. In 2004, FWP assessed funding and staffing needs to implement a CCAA in the upper Big Hole Valley. A USFWS Landowner Incentive Program grant funds a habitat biologist to work with landowners, agency personnel and interest groups to improve habitat to benefit Arctic grayling as well as other sympatric aquatic species. The biologist works with landowners, USFWS, Natural Resources and Conservation Service (NRCS), Department of Natural Resources and Conservation (DNRC), Big Hole Watershed Committee, Trout Unlimited, and Big Hole River Foundation, to develop interest, enhance relationships and establish partners for the CCAA Program.

The CCAA aids landowners that agree to modify land management activities and conduct restoration projects that substantively and beneficially affect grayling. In exchange, the enrolled landowners are provided assurances, throughout the duration of the CCAA, that no further government regulations will be required if grayling are listed under the ESA. This process is authorized by the USFWS through an Enhancement of Survival Permit, which FWP received on August 1, 2006. Under the CCAA, FWP holds an ESA Section 10(a)(1)(A) Enhancement of Survival Permit issued by the USFWS. FWP issues Certificates of Inclusion to non-federal property owners within the project area who have enrolled, agree to comply with all stipulations of the CCAA and develop an approved site-specific plan. Site-specific plans are being developed with each landowner by an interdisciplinary technical team made up of individuals representing FWP, USFWS, NRCS, and DNRC. As of 1 January 2010, 30 landowners had signed up 152,109 of private and 6,030 acres of State lease land for this program.

Adfluvial Grayling Population

Adfluvial Arctic grayling spend the majority of their lives inhabiting lakes and use inlet or outlet streams for spawning. These grayling have been introduced into many locations and are distributed throughout Montana in mountain lakes (Figure 3). Native adfluvial populations in Montana were limited to the Red Rock Lakes, and a few lakes in the Big Hole Drainage. Historically, the Red Rock population spawned in numerous tributaries to Upper and Lower Red Rock lakes. Currently, only Red Rock and Odell Creeks appear to support spawning by endemic adfluvial Arctic grayling (Boltz 2006). Declines in this population are attributed to habitat alteration, drought conditions, reduced stream flows, siltation, and predation or competition from non-native fish species (Unthank 1989). Native populations in the Big Hole include Mussigbrod, Pintler and Miner Lakes. These populations have been supplemented with stocked grayling but are currently stable.

lakegraylingdistribution
Figure 3. Distribution of adfluvial grayling populations in Montana (red) and Red Rock Lakes population (green).

An adfluvial grayling population derived from Red Rock Lakes exists at Rogers Lake in northwest Montana. Locations for additional brood stocks are being explored. Other adfluvial populations in Montana are derived from mixed genetic stocks, which may include Red Rocks, Madison, Big Hole, Rogers Lake, or Red Meadow grayling strains. These introduced mountain lake populations are maintaining self-sustaining viable populations with little to no human intervention.

References

  • Armstrong, R. H. 1986. A review of Arctic grayling studies in Alaska, 1952-1982. Biological Papers of the University of Alaska, 23:3-17.
  • Boltz, G. D. and L.R. Kaeding. 2006. Seasonal Migrations of Lacustrine Arctic Grayling in waters of Red Rock Lakes National Wildlife Refuge, Montana - a progress report. U.S. Fish and Wildlife Service, Bozeman.
  • Byorth, P.A. 1991. Population surveys and analysis of fall and winter movements of Arctic grayling in the Big Hole River. 1991 Annual Report. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Byorth, P. A. 1993. Big Hole River Arctic grayling recovery project: Annual monitoring report 1992.��Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife, and Parks, Bozeman.
  • _____. 1994. Big Hole River Arctic grayling recovery project: Annual monitoring report 1993. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife, and Parks, Bozeman.
  • _____. 1995. Big Hole River Arctic grayling recovery project: Annual monitoring report 1994. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Fish, Wildlife, and Parks, Bozeman.
  • _____. 1996. Big Hole River Arctic grayling recovery project: Annual monitoring report 1996. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Fish, Wildlife, and Parks, Bozeman.
  • _____. 1997. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 1996. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Byorth, P. A. and J. P. Magee. 1996. Big Hole River Arctic grayling recovery project: Annual monitoring�report 1995. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Fish, Wildlife, and Parks, Bozeman.
  • Clark, R. A. 1992. Influence of stream flows and stock size on recruitment of Arctic grayling (Thymallus arcticus) in the Chena River, Alaska. Canadian Journal of Fisheries and Aquatic Sciences 49(5):1027-1034.
  • Fluvial Arctic Grayling Workgroup. 1995. Restoration plan for Montana fluvial Arctic grayling. Montana Department of Fish, Wildlife, and Parks, Helena.
  • Holton, G. D. 1980. The riddle of existence: fishes of special concern. Montana Outdoors 11(1):2-6.
  • Kaya, C. M. 1991. Rheotactic differentiation between fluvial and lacustrine populations of Arctic grayling (Thymallus arcticus), and implications for the only remaining indigenous population of fluvial �Montana grayling�. Canadian Journal of Fisheries and Aquatic Sciences 48:53-59.
  • _____. 1992a. Review of the decline and status of fluvial Arctic grayling (Thymallus arcticus), in Montana. Proceedings of Montana Academy of Sciences 52:43-70.
  • _____. 1992b. Restoration of fluvial Arctic grayling to Montana streams: assessment of reintroduction potential of streams in the native range, the upper Missouri River drainage above Great Falls. Prepared for: Montana Chapter of the American Fisheries Society and Montana Department of Fish, Wildlife, and Parks, Bozeman.
  • Kaya, C. M. and E. D. Jeanes. 1995. Retention of adaptive rheotactic behavior by F1 fluvial Arctic grayling. Transactions of the American Fisheries Society 124:453-457.
  • Lamothe, P., and J. Magee. 2004. Linking Arctic grayling abundance to physical habitat parameters in the upper Big Hole River, Montana. Montana Fish, Wildlife, and Parks, Dillon. 29 pp.
  • Lamothe, P.J. and J.P. Magee. 2004. Reintroducing fluvial Arctic grayling (Thymallus arcticus) to the Upper Ruby River, MT � a progress report. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Leary, R. F. 1991. Establishment, maintenance, and use of a genetic reserve of Big Hole River Arctic grayling. Wild Trout and Salmon Genetics Laboratory Report 91/5. University of Montana, Missoula.
  • Liknes, G. A., and W. R. Gould. 1987. The distribution, habitat, and population characteristics of fluvial Arctic grayling (Thymallus arcticus) in Montana. Northwest Science 61(2):122-129.
  • Lohr, S. C., P. A. Byorth, C. M. Kaya, and W. P. Dwyer. 1996. High temperature tolerances of fluvial Arctic grayling and comparisons with summer water temperatures of the Big Hole River, Montana. Transactions of the American Fisheries Society 125:933-939.
  • Magee, J.P. 1999. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 1998. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Magee, J.P. 2002. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 2000-2001. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Magee, J. P. and P. A. Byorth. 1994. Competitive interactions of fluvial Arctic grayling (Thymallus arcticus) and brook trout (Salvelinus fontinalis) in the upper Big Hole River, Montana. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department, of Fish, Wildlife, and Parks, Bozeman.
  • _____. 1995. Competitive interactions of fluvial Arctic grayling and sympatric species in the Big Hole River drainage, Montana. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Fish, Wildlife, and Parks, Bozeman.
  • _____. 1998. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 1997. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Magee, J.P. and P.J. Lamothe. 2003. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 2002. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Magee, J.P. and S.T. Opitz. 2000. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 1998. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Magee, J.P., and E.N. Rens, and P.J. Lamothe. 2005. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 2004. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • _____. 2006. Big Hole River Arctic Grayling Recovery Project: Annual monitoring report 2005. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife and Parks, Bozeman.
  • Oswald, R. A. 1990. Big Hole grayling work report: Fall field season 1990. Report to Fluvial Arctic Grayling Workgroup. Montana Department of Fish, Wildlife, and Parks, Dillon.
  • Rens, E.N., and J.P. Magee. 2007. Montana Arctic Grayling Annual Monitoring Report, 2006. Submitted to: Fluvial Arctic Grayling Workgroup. Montana Fish, Wildlife & Parks, Bozeman.
  • Shepard, B. B., and R. A. Oswald. 1989. Timing, location, and population characteristics of spawning Montana Arctic grayling (Thymallus arcticus montanus [Milner]) in the Big Hole River drainage, 1988. Montana Department of Fish, Wildlife, and Parks, Bozeman.
  • Skaar, D. 1989. Distribution, relative abundance, and habitat utilization of Arctic grayling (Thymallus arcticus) in the upper Big Hole River drainage, Montana, July 5 to September 8, 1988. Report to: Montana Natural Heritage Program, Beaverhead National Forest, and Montana Department. of Fish, Wildlife, and Parks, Bozeman.
  • U. S. Fish and Wildlife Service. 1991. Endangered and threatened wildlife and plants; animal candidate review for listing as endangered or threatened species, notice of review. Federal Register 56(225):58804-58836.
  • _____. 1994. Endangered and threatened wildlife and plants; finding on a petition to list the fluvial population of the Arctic grayling as endangered. Federal Register 59(141):37738.
  • Unthank, A. 1989. Historical overview of the Red Rock Lakes National Wilderness, an aquatic history 1899 � 1977. Unpublished report. U.S. Fish and Wildlife Service, Kalispell Field Station, Creston, Montana. 244 pp.
  • Vincent, R. E. 1962. Biogeographical and biologic factors contributing to the decline of Arctic grayling (Thymallus arcticus [Pallus]) in Michigan and Montana. Ph.D. Dissertation, University of Michigan, Ann Arbor.
  • Williams, J. E., J.E. Johnson, D. A. Hendrickson, S. Contreras-Balderas, J. D. Williams, M. Navarro-Mendoza, D. E. McAllister, and J. E. Deacon. 1989. Fishes of North America endangered, threatened, or of special concern: 1989. Fisheries 14(6):2-20.
s2Member®