Damped trophic cascades driven by fishing in model marine ecosystems

Ken Haste Andersen, Martin Pedersen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The largest perturbation on upper trophic levels of many marine ecosystems stems from fishing. The reaction of the ecosystem goes beyond the trophic levels directly targeted by the fishery. This reaction has been described either as a change in slope of the overall size spectrum or as a trophic cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to explore how marine ecosystems might react to perturbations from different types of fishing pressure. The model explicitly resolves the whole life history of fish, from larvae to adults. The results show that fishing does not change the overall slope of the size spectrum, but depletes the largest individuals and induces trophic cascades. A trophic cascade can propagate both up and down in trophic levels driven by a combination of changes in predation mortality and food limitation. The cascade is damped as it comes further away from the perturbed trophic level. Fishing on several trophic levels leads to a disappearance of the signature of the trophic cascade. Differences in fishing patterns among ecosystems might influence whether a trophic cascade is observed.
Original languageEnglish
JournalRoyal Society of London. Proceedings. Biological Sciences
Volume277
Issue number1682
Pages (from-to)795-802
ISSN0962-8452
DOIs
Publication statusPublished - 2010

Keywords

  • size spectrum
  • community model
  • ecosystem approach to fisheries management

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