Evolutionary Ecology

, Volume 9, Issue 4, pp 411–420

First access to territorial space and exposure to strong predation pressure: A conflict in early emerging Atlantic salmon (Salmo salar L.) fry

  • Eva Brännäs
Article

Summary

This work aimed to elucidate conflicting factors that may explain the narrow and synchronous emergence in salmonids. Fry are highly vulnerable to predation and stand a better chance of surviving if they emerge synchronously. On the other hand, fry that leave the gravel first should increase their chance of obtaining one of the limited number of feeding territories. The risk involved in early emergence for Atlantic salmon fry was evaluated by exposing them to predatorySalmo trutta. Yolk sac alevins were incubated in an artificial redd in order to catch them by their time of emergence. Early-, peak- and late-emerging fry were then successively marked and transferred to flume tanks in which the predators were either present from the start or not introduced until all fry had been added. When the predators were initially present, the predation pressure differed depending on the time of fry emergence, resulting in survival rates of 11.6, 44.9 and 51% in early-, peak- and late-emerging fry, respectively. By assuming that the predation rate of the three emergence groups was dependent both on time of emergence and fry density the survival rates were calculated to be 7.5, 41.1 and 53.5% in groups I, II and III, respectively. These figures corresponded well to the observed rates. When the predators were added after completed emergence the resulting survival rates were 56.9, 39.7 and 25.2% in early-, peak- and late-emerging fry, respectively. Thus, predation after complete emergence gave a survival probability that varied across the three emergence-date groups, despite being exposed to a predator during the same number of days. The presence of fish predators in combination with a limited territorial space seems to make both early and late emergence hazardous and favours synchronous swimming movements.

Keywords

Atlantic salmon Salmo salar timing of emergence predation fry alevins functional response 

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References

  1. Backiel, T. and LeCren, E.D. (1978) Some density relationships of fish population parameters. InEcology of freshwater fish production, (S.D. Gerking, ed.), pp. 279–302. Oxford University Press, Oxford.Google Scholar
  2. Bams, R.A. (1969) Adaptations of sockeye salmon associated with incubation in stream gravels. InSymposium on salmon and trout in streams (T.G. Northcote, ed.), pp. 71–87. University of British Columbia, Vancouver.Google Scholar
  3. Begon, M. and Mortimer, M. (1986)Population Ecology; A Unified Study of Animals and Plants, 2nd edn, pp. 117–52. Blackwell Scientific Publications, Oxford.Google Scholar
  4. Brännäs, E. (1987) Influence of photoperiod and temperature on hatching and emergence of Baltic salmon (Salmo salar) fry.Can. J. Zool. 65 1503–8.Google Scholar
  5. Chandler, G.L. and Bjornn, T.C. (1988) Abundance, growth, and interactions of juvenile steelhead relative to time of emergence.Trans. Am. Fish. Soc. 117 432–43.Google Scholar
  6. Chapman, D.W. (1962) Aggressive behaviour in juvenile coho salmon as a cause of emigration.J. Fish. Res. Board Can. 11 1047–80.Google Scholar
  7. Chapman, D.W. (1966) Food and space as regulators of salmonid populations in streams.Am. Nat. 100 345–57.Google Scholar
  8. Cole, K.S. and Noakes, D.L.G. (1980) Development of early social behaviour of rainbow trout,Salmo gairdneri.Behav. Process. 5 97–112.Google Scholar
  9. Dill, P.A. (1970) On the development of diel activity rhythms in Atlantic salmon and Rainbow trout.Ph.D. Thesis, University of Western Ontario, London, Ontario.Google Scholar
  10. Dill, P.A. (1977) Development of behaviour in alevins of Atlantic salmon (Salmo salar) and Rainbow trout (S. gairdneri).Anim. Behav. 25 116–21.Google Scholar
  11. Dill, L.M. and Fraser, A.H.G. (1984) Risk of predation and the feeding behaviour of juvenile coho salmon (Onchorhynchus kisutch).Behav. Ecol. Sociobiol. 16 65–71.Google Scholar
  12. Elliott, J.M. (1986) Spatial distribution and behavioural movements of migratory trout (Salmo trutta) in a lake district stream.J. Anim. Ecol. 55 907–22.Google Scholar
  13. Faush, K.D. and White, R.J. (1986) Competition among juveniles of coho salmon, brook trout, and brown trout in a laboratory stream, and implications for Great Lakes tributaries.Trans. Am. Fish. Soc. 115 363–81.Google Scholar
  14. Fresh, K.L. and Schroder, S.L. (1987) Influence of the abundance, size, and yolk reserves of juvenile chum salmon (Onchorhynchus keta) on predation by freshwater fishes in a small coastal stream.Can. J. Fish. Aquat. Sci. 44 236–43.Google Scholar
  15. Godin, J-G.J. (1980) Temporal aspects of juvenile pink salmon (Onchorhynchus gorbusha) emergence from a simulated gravel redd.Can. J. Zool. 58(5 735–44.Google Scholar
  16. Godin, J-G.J. (1982) Migrations of salmonid fishes during early life history phases: daily and annual timing. InSalmon and trout migratory behaviour (E.L. Brannon and E.O. Salo, eds), pp. 22–50. University of Washington Press, Seattle.Google Scholar
  17. Gustavson-Marjanen, K.I. and Dowse, H.B. (1983) Seasonal and diel patterns of emergence from the redd of Atlantic salmon (Salmo salar) fry.Can. J. Fish. Aquat. Sci. 40 813–17.Google Scholar
  18. Holling, C.S. (1959) The components of predation as revealed by a study of small-mammal predation of the European pine sawfly.Can. Entomol. 91 293–320.Google Scholar
  19. Kalleberg, H. (1958) Observations in a stream tank of territoriality and competition in juvenile salmon and trout (Salmo salar L. andS. trutta L.).Rep. Inst. Freshwater Res., Drottningholm 39 55–98.Google Scholar
  20. Mason, J.C. and Chapman, D.W. (1965) Significance of early emergence, environmental rearing capacity, and behavioural ecology of juvenile coho salmon in stream channels.J. Fish. Res. Board Can. 22 173–90.Google Scholar
  21. Metcalfe, N.B. and Thorpe, J.E. (1992) Early predictors of life-history events: the link between first feeding date, dominance and seaward migration in Atlantic salmon,Salmo salar L.J. Fish Biol. 41 93–9.Google Scholar
  22. Metcalfe, N.B., Huntingford, F.A., Graham, W.D. and Thorpe, J.E. (1989) Early social status and the development of life-history strategies in Atlantic salmon.Proc. R. Soc. Lond. B 236 7–19.Google Scholar
  23. Northcote, T.G. (1978) Migratory strategies and production in freshwater fishes. InEcology of Freshwater Fish Production (S.D. Gerking, ed.), pp. 326–59. Blackwell Scientific Publications, Oxford.Google Scholar
  24. Peterman, R.M. and Gatto, M. (1978) Estimation of functional responses of predators on juvenile salmon.J. Fish. Res. Board Can. 35 797–808.Google Scholar
  25. Pulliam, H.R. and Caraco, T. (1984) Living in groups: is there an optimal group size? InBehavioral ecology; an evolutionary approach, 2nd edn (J.R. Krebs and N.B. Davies, eds), pp. 122–48. Blackwell Scientific Publications, Oxford.Google Scholar
  26. Slaney, P.A. and Northcote, T.G. (1974) Effects of prey abundance on density and territorial behaviour of young rainbow troutSalmo gairdneri in laboratory stream channels.J. Fish. Res. Board Can. 31 1201–9.Google Scholar
  27. Solomon, D.J. (1982) Migration and dispersal of juvenile brown and sea trout. InSalmon and trout migratory behaviour (E.L. Brannon and E.O. Salo, eds), pp. 136–45. University of Washington Press, Seattle.Google Scholar
  28. Sweeney, B.W. and Vannote, R.L. (1982) Population synchrony in mayflies: a predator satiation hypothesis.Evolution 36 810–21.Google Scholar
  29. Symons, P.E.K. (1974) Territorial behaviour of juvenile Atlantic salmon reduces predation by brook trout.Can J. Zool. 52 677–9.Google Scholar
  30. Taylor, E.B. and McPhail, J.D. (1985) Burst swimming and size-related predation of newly emerged coho salmon (Onchorhynchus kisutch).Trans. Am. Fish. Soc. 114 546–51.Google Scholar

Copyright information

© Chapman & Hall 1995

Authors and Affiliations

  • Eva Brännäs
    • 1
  1. 1.Department of Animal EcologyUniversity of UmeåUmeåSweden
  2. 2.Department of AquacultureSwedish University of Agricultural SciencesUmeåSweden

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