Migrations in the Marine Environment

Abstract

The oceans cover 71% of the Earth’s surface and contain a tremendous volume of approximately 1.3 × 10⁹ km³. Although biodiversity of the littoral communities may be as high as in terrestrial ecosystems, the pelagic communities are relatively poor. The origin and problems of biodiversity of the pelagial were discussed by Angel (1993). Nevertheless, compared to lakes, diversity is rich with species varying tremendously in morphology and behaviour. This results in variable niches and complex food webs . Also the adaptive significance of DVM is likely to be more diverse. In lakes, predator evasion is considered the principal if not the only reason for the occurrence of DVM and this might be an important ultimate aspect in the marine biotope as well, although other adaptive reasons cannot be excluded a priori. In a very extensive, and one is inclined to think an exhaustive review, Pearre (2003) stressed the role of food as an ultimate as well as proximate factor. Food of course is important and food niche separation might be an adaptive reason of vertical migration too. DVM is not an isolated phenomenon, but represents a part of the composite strategies required for co-existence in the pelagic community .

ArticleNote

To study the literature on DVM in the marine environment is like a “mer à boire”.