Abstract
Arctic charr, Salvelinus alpinus, tend to form stunted populations presumably due to competition for limited resources. In this context a long-term intensive fishery programme aiming at reducing charr density, and thereby increasing growth and harvestable sizes, was initiated in the early 1980s in a Norwegian alpine lake. Here we present long-term data on catch statistics and changes in mean weights of charr caught with gill nets on spawning grounds, as well as changes in mean weight of juvenile charr caught with funnel traps during the 1990s. Furthermore, we present results from shorter-term studies on growth, size- and age-distribution, and size-related habitat and resource utilisation of Arctic charr and brown trout, Salmo trutta, in this lake. Mean weight (± SD) of charr caught on the spawning grounds increased significantly from 129.8 g (±11.9) in the years 1982–1990 to 213.1 g (±37.8) in the years 1996–1999, whereas catch per unit of effort decreased significantly. Mean weight of juveniles caught in funnel traps increased significantly from 21.2 g (±6.9) in 1993 to 41.9 g (±14.8) in 1999. Apparently the increase in weight of spawning charr coincided with the onset of trap fishing for juvenile charr. Compared to generally shallow dwelling trout, charr grew rapidly and were generally found in deeper areas of the lake. Charr went through a distinct size-related niche shift from mainly consuming small zooplankton in the pelagic to consuming large benthic prey in shallower waters. Resource and habitat utilisation in different size-groups of charr and trout are discussed with respect to possible competitive and predatory intra- and interspecific interactions, and with regard to management of charr populations.
Similar content being viewed by others
References cited
Amundsen, P.-A., A. Klemetsen & P.E. Grotnes. 1993. Rehabilitation of a stunted population of Arctic char by intensive fishing. N. Amer. J. Fish. Manag. 13: 483–491.
Backiel, T. & E.D. Le Cren. 1978. Some density relationships for fish population parameters. pp. 279-302. In: S.D. Gerking (ed.) Ecology of Freshwater Fish Production, Blackwell Scientific Publications, Oxford.
Beverton, R.J. & S.J. Holt. 1957. On the dynamics of exploited fish populations. Fishery Investigations, London. 533 pp.
Ebenman, B. & L. Persson. 1988. Introduction. Dynamics of sizestructured populations: an overview. pp. 3–9. In: B. Ebenman & L. Persson (ed.) Size-Structured Populations: Ecology and Evolution, Springer-Verlag, London.
Filipsson, O. & G. Svärdson. 1976. Principles for the management of charr populations. Information from the Institute of Freshwater Research, Drottningholm (2). 79 pp. (in Swedish).
Forseth, T., O. Ugedal & B. Jonsson. 1994. The energy budget, niche shift, reproduction and growth in a population of Arctic char, Salvelinus alpinus. J. Anim. Ecol. 63: 116–126.
Haugen, T.D. & T.A. Rygg. 1996. Food-and habitat-segregation in sympatric grayling and brown trout. J. Fish Biol. 49: 301–308.
Hindar, K. & B. Jonsson. 1982. Habitat and food segregation of dwarf and normal Arctic char (Salvelinus alpinus) from Vangsvatnet Lake, western Norway. Can. J. Fish. Aquat. Sci. 39: 1030–1045.
Jensen, K.W. 1977. On the dynamics and exploitation of the population of brown trout, Salmo trutta L., in Lake Øvre Heimdalsvatn, Southern Norway. Rep. Inst. Freshwat. Res. Drottningholm 56: 18–69.
Jonsson, B. 1989. Life history and habitat use of Norwegian brown trout (Salmo trutta L.). Freshwat. Biol. 21: 71–86.
Klemetsen, A., P.-A. Amundsen, H. Muladal, S. Rubach & J.I. Solbakken. 1989. Habitat shifts in a dense, resident Arctic charr, Salvelinus alpinus, population. Physiol. Ecol. Japan Spec. 1: 187–200.
L'Abée-Lund, J. H., A. Langeland & H. Sæ grov. 1992. Piscivory by brown trout Salmo trutta L. and Arctic charr Salvelinus alpinus (L.) in Norwegian lakes. J. Fish Biol. 41: 91–101.
L'Abée-Lund, J. H., A. Langeland, B. Jonsson & O. Ugedal. 1993. Spatial segregation by age and size in Arctic charr: a tradeoff between feeding possibility and risk of predation. J. Anim. Ecol. 62: 160–168.
Langeland, A. 1986. Heavy exploitation of a dence resident population of Arctic char in a mountain lake in Central Norway. N. Amer. J. Fish. Manag. 6: 519–525.
Langeland, A. 1995. Management of charr lakes. Nordic J. Freshwat. Res. 71: 68–80.
Langeland, A. & B. Jonsson. 1990. Management of stunted populations of Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta). pp. 396-405. In: W.L.T van Densen, B. Steinmetz & R.H. Hughes (ed.) Management of Freshwater Fisheries, Pudoc, Wageningen.
Langeland, A. & J.H. L'Abée-Lund. 1996. Habitat use, size and age structure in sympatric brown trout (Salmo trutta) and Arctic charr (Salvelinus alpinus) stocks: resistance of populations to change following harvest. Ecol. Freshwat. Fish. 5: 49–58.
Langeland, A. & T. Pedersen. 2000. A 27-year study of brown trout population dynamics and exploitation in Lake Songsjøen, central Norway. J. Fish Biol. 57: 1227–1244.
Nilsson, N.-A. 1960. Seasonal fluctuations in food segregation of trout, char and whitefish in 14 north-Swedish lakes. Rep. Inst. Freshwat. Res. Drottningholm 41: 185–205.
Nilsson, N.-A. 1963. Interaction between trout and char in Scandinavia. Trans. Amer. Fish. Soc. 92: 276–285.
Nilsson, N.-A. 1965. Food segregation between salmonid species in north Sweden. Rep. Inst. Freshwat. Res. Drottningholm 46: 58–78.
Nordeng, H. 1961. On the biology of char (Salmo alpinus L.) in Salangen, north Norway. Age and spawning frequency determined from scales and otoliths. Nytt Mag. Zool. 10: 67–123.
Svärdson, G. 1976. Inter-specific population dominance in fish communities of Scandinavian lakes. Rep. Inst. Freshwat. Res. Drottningholm 55: 144–171.
Werner, E. E. & J.F. Gilliam. 1984. The ontogenetic niche and species interactions in size-structured populations. Annual Rev. Ecol. Syst. 15: 393–425.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Jansen, P.A., Finstad, A.G. & Langeland, A. The Relevance of Individual Size to Management of Arctic Charr, Salvelinus Alpinus, Populations. Environmental Biology of Fishes 64, 313–320 (2002). https://doi.org/10.1023/A:1016009625754
Issue Date:
DOI: https://doi.org/10.1023/A:1016009625754