Abstract
Large-bodied, migratory life history forms of bull charr, Salvelinus confluentus, were historically abundant in northwestern North America, but many remaining populations of this now-threatened species presently persist as small-bodied residents isolated in headwater streams. We examined whether the migratory form has been lost from headwater populations of bull charr and their potential for re-establishment. Upstream and downstream movement of bull charr and other salmonids from three tributary populations in the Bitterroot River drainage, Montana, was measured with weirs over a 17-month period. The migratory life history was rare or absent in two tributaries but still present at a low level in a third. In contrast, substantial numbers (n = 1745) of juvenile and adults of other salmonids (brown trout, Salmo trutta, cutthroat trout, Oncorhynchus clarki, and mountain whitefish, Prosopium williamsoni) were captured near tributary mouths, indicating a migratory life history was common in other species. Apparent decline of the migratory life history in bull charr was not directly related to damming suggesting other downstream mortality factors (predation, temperature) also are involved. Isolated, nonmigratory forms have increased risk of extinction, and restoration of the population connectivity via the re-establishment of migratory stocks is an important conservation goal for bull charr recovery. However, the factors governing migratory tendency remain unclear.
Similar content being viewed by others
References cited
Dunham, J.B., G.L. Vinyard & B.E. Rieman. 1997. Habitat fragmentation and extinction risk of Lahontan cutthroat trout. N. Amer. J. Fish. Manage. 17: 1126–1133.
Elliott, J.M. 1987. Population regulation in contrasting populations of trout Salmo trutta in two lake district streams. J. Anim. Ecol. 56: 83–98.
Fernet, D.A. & J. O'Neil. 1997. Use of radio telemetry to document seasonal movements and spawning locations for bull trout in relation to a newly created reservoir. pp. 427–434. In: W.C. Mackay, M.K. Brewin & M. Monita (ed.) Friends of the Bull Trout Conference Proceedings, Trout Unlimited Canada, Calgary.
Fitch, L. 1997. Bull trout in southwestern Alberta: notes on historical and current distribution. pp. 147–160. In: W.C. Mackay, M.K. Brewin & M. Monita (ed.) Friends of the Bull Trout Conference Proceedings, Trout Unlimited Canada, Calgary.
Fraley, J.J. & B.B. Shepard. 1989. Life history, ecology, and population status of migratory bull trout (Salvelinus confluentus) in the Flathead Lake and river system, Montana. Northwest Sci. 63: 133–143.
Gross, M.T. 1987. Evolution of diadromy in fishes. Amer. Fish. Soc. Symp. 1: 14–25.
Haas, G.R. & J.D. McPhail. 1991. Systematics and distributions of Dolly Varden (Salvelinus malma) and bull trout (Salvelinus confluentus) in North America. Can. J. Fish. Aquat. Sci. 48: 2191–2211.
Healey, M.C. & A. Prince. 1995. Scales of variation in life history tactics of Pacific salmon and the conservation of phenotype and genotype. Amer. Fish. Soc. Symp. 17: 176–184.
Hindar, K., B. Johnson, N. Ryman & G. Ståhl. 1991. Genetic relationships among landlocked, resident, and anadromous brown trout, Salmo trutta L. Heredity 66: 83–91.
Jakober, M.J., T.E. McMahon, R.F. Thurow & C.G. Clancy. 1998. Role of stream ice on fall and winter movements and habitat use by bull trout and cutthroat trout in Montana headwater streams. Trans. Amer. Fish. Soc. 127: 223–235.
Jonsson, B. & N. Jonsson. 1993. Partial migration: niche shift versus sexual maturation in fishes. Rev. Fish Biol. Fish. 3: 348–365.
Jonsson, B., S. Skúlason, S. Snorrason, O.T. Sandlund, H.J. Malmquist, P.M. Jonasson, R. Gydemo & T. Lindem. 1988. Life history variation of polymorphic Arctic charr (Salvelinus alpinus) in Thingvallavatn, Iceland. Can. J. Fish. Aquat. Sci. 45: 1537–1545.
McCart, P. 1997. Bull trout in Alberta: a review. pp. 191–207. In: W.C. Mackay, M.K. Brewin & M. Monita (ed.) Friends of the Bull Trout Conference Proceedings, Trout Unlimited Canada, Calgary.
Morita, K., S. Yamamoto & N. Hoshino. 2000. Extreme life history change of white-spotted char (Salvelinus leucomaenis) after damming. Can. J. Fish. Aquat. Sci. 57: 1300–1306.
Nelson, M.L. 1999. Evaluation of the potential for 'resident' bull trout to re-establish the migratory life-form. M.S. Thesis, Montana State University, Bozeman. 72 pp.
Nordeng, H. 1983. Solution to the 'char problem' based on Arctic char (Salvelinus alpinus) in Norway. Can. J. Fish. Aquat. Sci. 40: 1372–1387.
Northcote, T.G. 1992. Migration and residency in stream salmonids - some ecological considerations and evolutionary consequences. Nordic J. Freshw. Res. 67: 5–17.
Northcote, T.G. 1997. Potamodromy in Salmonidae - living and moving in the fast lane. N. Amer. J. Fish. Manage. 17: 1029–1045.
Riehle, M., W. Weber, A.M. Stuart, S.L. Thiesfeld & D.E. Ratliff. 1997. Progress report of the multi-agency study of bull trout in the Metolius River system, Oregon. pp. 137–144. In: W.C. Mackay, M.K. Brewin & M. Monita (ed.) Friends of the Bull Trout Conference Proceedings, Trout Unlimited Canada, Calgary.
Rieman, B.E., D.C. Lee & R.F. Thurow. 1997. Distribution, status, and likely trends of bull trout within the Columbia River and Klamath River basins. N. Amer. J. Fish. Manage. 17: 1111–1125.
Saffel, P.D. & D.L. Scarnecchia. 1995. Habitat use by juvenile bull trout in belt-series geology watersheds of northern Idaho. Northwest Sci. 69: 304–317.
Skúlason, S. & T.B. Smith. 1995. Resource polymorphisms in vertebrates. Trends Ecol. Evol. 10: 366–370.
Stelfox, J.D. 1997. Seasonal movements, growth, survival and population status of the adfluvial bull trout population in Lower Kananaskis Lake, Alberta. pp. 309–316. In: W.C. Mackay, M.K. Brewin & M. Monita (ed.) Friends of the Bull Trout Conference Proceedings, Trout Unlimited Canada, Calgary.
Swanberg, T. 1997a. Movements of and habitat use by fluvial bull trout in the Blackfoot River, Montana. Trans. Amer. Fish. Soc. 126: 735–746.
Swanberg, T.R. 1997b. Movements of bull trout (Salvelinus confluentus) in the Clark Fork River system after transport upstream of Milltown Dam. Northwest Sci. 71: 313–317.
Thurow, R.F., D.C. Lee & B.E. Rieman. 1997. Distribution and status of seven native salmonids in the Interior Columbia River Basin and portions of the Klamath River and Great Basins. N. Amer. J. Fish. Manage. 17: 1094–1110.
USFWS (U.S. Fish and Wildlife Service). 1998. Determination of threatened status for the Klamath River and Columbia River distinct population segments of bull trout. Final rule. Federal Reg. 63(111): 31647–31674.
Verspoor, E. & L.J. Cole. 1989. Genetically distinct sympatric populations of resident and anadromous Atlantic salmon, Salmo salar. Can. J. Zool. 67: 1453–1461.
Vuorinen, J. & O.K. Berg. 1989. Genetic divergence of anadromous and nonanadromous Atlantic salmon (Salmo salar) in the River Namsen, Norway. Can. J. Fish. Aquat. Sci. 46: 406–409.
Wood, C.C. & C.J. Foote. 1996. Evidence for sympatric genetic divergence of anadromous and nonanadromous morphs of sockeye salmon (Oncorhynchus nerka). Evolution 50: 1265–1279.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Nelson, M.L., McMahon, T.E. & Thurow, R.F. Decline of the Migratory Form in Bull Charr, Salvelinus Confluentus, and Implications for Conservation. Environmental Biology of Fishes 64, 321–332 (2002). https://doi.org/10.1023/A:1016062708588
Issue Date:
DOI: https://doi.org/10.1023/A:1016062708588