Marine Biology

, Volume 63, Issue 1, pp 39–49 | Cite as

The role of behavioral responses to predators in modifying urchins' (Strongylocentrotus droebachiensis) destructive grazing and seasonal foraging patterns

  • B. B. Bernstein
  • B. E. Williams
  • K. H. Mann


We documented spatial and temporal patterns of urchins (Strongylocentrotus droebachiensis) and periwinkles (Littorina littorea) in three habitats: a persistent Laminaria longicruris and L. digitata bed; an urchin dominated barrens, and the edge of the kelp bed that formed a boundary between the two. Urchins were rare in the kelp and, when present, always large and well hidden, a pattern we interpret as a response to crab and lobster predation. Urchins were abundant in the barrens, and, in the summer when predaceous fish were active during the day, foraged only at nigh. We observed the formation of a dense urchin feeding front along the kelp bed edge, and these urchins remained exposed and feeding even during the summer. Laboratory experiments demonstrated that aggregations are an effective defense against some predators, and that the presence of crabs increases the tendency of large urchins to aggregate. We hypothesize that healthy Laminaria spp. beds persist because kelp bed associated predators keep urchins at low densities and in hiding. A reduction in predation pressure permits urchin densities to increase to the point where they form aggregations, which provide better defense than hiding. These aggregations then graze destructively on Laminaria spp., forming barrens. These barrens seem to be a new, stable configuration of the system.


Laboratory Experiment Behavioral Response Temporal Pattern Predation Pressure Good Defense 
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Literature Cited

  1. Breen, P. A. and K. H. Mann: Destructive grazing of kelp by sea urchins in Eastern Canada. J. Fish. Res. Bd Can. 33, 1278–1283 (1976a)Google Scholar
  2. Breen, P. A. and K. H. Mann: Changing lobster abundance and the destruction of kelp beds by sea urchins. Mar. Biol. 34, 137–142 (1976b)Google Scholar
  3. Chapman, A.R.O.: Stability of sea urchin dominated barren grounds following destructive grazing of kelp in St. Margaret's Bay, Eastern Canada. Mar. Biol. (In press)Google Scholar
  4. Dayton, P. K.: Competition, disturbance, and community organization: The provision and subsequent utilization of space in a rocky intertidal community. Ecol. Monogr. 41, 351–389 (1971)Google Scholar
  5. Drummond-Davis, N.: Population estimates of the rock crab, Cancer irroratus, in a kelp bed and some aspects of its feeding. 50 pp. M.S. Thesis, Dalhousie University (1978)Google Scholar
  6. Evans, P. D. and K. H. Mann: Selection of prey by American lobster (Homarus americanus) when offered a choice between sea urchins and crabs. J. Fish. Res. Bd Can. 34, 2203–2207 (1977)Google Scholar
  7. Garnick, E.: Behavioural ecology of Strongylocentrotus droebachiensis (Muller) (Echinodermata: Echinoidea). Oecologia (Berl.) 37, 77–84 (1978)Google Scholar
  8. Hirtle, R. W. M. and K. H. Mann: Distance chemoreception and vision in the selection of prey by American lobster (Homarus americanus). J. Fish. Res. Bd Can. 35, 1006–1008 (1978)Google Scholar
  9. Holling, C. S.: Resilience and stability of ecological systems. Ann. Rev. Ecol. Syst. 4, 1–23 (1973)Google Scholar
  10. Johanssen, F.: Natural history of the cunner (Tauroglabrus adspersus Walbaum). Contrib. Can. Biol. N. S. 2, 423–468 (1925)Google Scholar
  11. Jones, D. D.: The application of catastrophe theory to ecological systems. International Institute for Applied Systems Analysis (IIASA) Research Report. Schloss Laxenburg 2361 Laxenburg, Austria (1975)Google Scholar
  12. Lang, C. and K. H. Mann: Changes in sea urchin populations after the destruction of kelp beds. Mar. Biol. 36, 321–326 (1976)Google Scholar
  13. Levin, S. A. and R. T. Paine: Disturbance, patch formation, and community structure. Proc. Nat. Acad. Sci. USA 71, 2744–2747 (1974)Google Scholar
  14. Loucks, O. L.: Evolution of diversity, efficiency, and community stability. Am. Zool. 10, 17–25 (1970)Google Scholar
  15. Mann, K. H.: Ecological energetics of the seaweed zone in a marine bay on the Atlantic Coast of Canada. I. Zonation and biomass of seaweeds. Mar. Biol. 12, 1–10 (1972)Google Scholar
  16. Mann, K. H.: Destruction of kelp-beds by sea urchins: A cyclical phenomenon or irreversible degradation? Helgoländer wiss. Meeresunters. 30, 455–467 (1977)Google Scholar
  17. Mann, K. H. and P. A. Breen: The relation between lobster abundance, sea urchins and kelp beds. J. Fish. Res. Bd Can. 29, 603–609 (1972)Google Scholar
  18. Mattison, J. E., J. D. Trent, A. L. Shanks, T. B. Akin and J. S. Pearse: Movement and feeding activity of red sea urchins (Strongylocentrotus franciscanus) adjacent to a kelp forest. Mar. Biol. 39, 25–30 (1977)Google Scholar
  19. Miller, R. J. and K. H. Mann: Ecological energetics of the seaweed zone in a marine bay on the Atlantic Coast of Canada. III. Energy transformations by sea urchins. Mar. Biol. 18, 99–114 (1973)Google Scholar
  20. Russo, A. R.: Dispersion and food differences between two populations of the sea urchin Strongylocentrotus franciscanus. J. Biogeogr. 6, 407–414 (1979)Google Scholar
  21. Sokal, R. R. and F. J. Rohlf: Biometry. 776 pp. San Francisco: W. H. Freeman 1969Google Scholar
  22. Vadas, R. L.: The ecology of Agarum and the kelp bed community. 282 pp. Ph. D. Thesis, University of Washington (1968)Google Scholar
  23. Wharton, W. G.: The distribution of sea urchin dominated barren grounds along the south shore of Nova Scotia. In: Proceedings of the workshop on the effects of commercial algal/animal harvesting on sea urchin grazing dynamics. Ed. by J. Pringle, G. Sharp and J. Caddy. Canadian Technical Report of Fisheries and Aquatic Sciences 954 (1980)Google Scholar
  24. Zeeman, E. C.: Catastrophe theory. Scientific American, April 1976, 65–83 (1976)Google Scholar

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • B. B. Bernstein
    • 1
  • B. E. Williams
    • 1
  • K. H. Mann
    • 1
  1. 1.Department of BiologyDalhousie UniversityHalifaxCanada

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