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The natural climatic variation had an impact in the past on the geographical distribution, migration and abundance of North Atlantic fish. The intense cold period that has marked Atlantic waters in the 1990s was undoubtedly a significant factor in the stock collapse: the poor condition of fish and poor survival rate of eggs and larva have very likely worsened the situation of populations subjected to intense exploitation. Logic sets similar responses in the future. It is possible to specify the reactions of some species to particular environmental dynamics despite the fact that North Atlantic dynamics are still unknown. Any consideration of marine ecosystem recovery in the Gulf of St. Lawrence must take into account the effects of the natural climatic variation and possible recent anthropogenic climatic change because they can influence the structure, operation and taxonomic composition of ecosystems, which are at the root of recovery. Despite the fact that it is possible to specify the reactions of certain species (such as capelin) to environmental changes, it is impossible to do so for most species and their interactions, and it is difficult to specify the climatic scenario on which to rely. Generally, recovery plans will not depend much on predictions of the influence of the climatic changes on the ecosystem, but these plans could have to be modified according to the inherent uncertainties of the climate, which is particularly true in this fast-changing era.
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