Ce. Mills, MEDUSAE, SIPHONOPHORES, AND CTENOPHORES AS PLANKTIVOROUS PREDATORS INCHANGING GLOBAL ECOSYSTEMS, ICES journal of marine science, 52(3-4), 1995, pp. 575-581
Medusae, siphonophores, and ctenophores are planktivorous predators op
erating at higher trophic levels in marine ecosystems of a wide range
of productivity. It has been hypothesized that high-productivity ecosy
stems such as areas of upwelling tend towards food chains dominated by
larger phytoplankton, large copepods, and ultimately many species of
fish rather than gelatinous predators; ecosystems with lower productiv
ity are characterized by small flagellate phytoplankton, small copepod
s, and ultimately numerous medusae and ctenophores. Evidence is provid
ed that medusae, siphonophores, and ctenophores are actually important
predators in both sorts of planktonic ecosystems, although uneven rep
orting in the literature may be cause for underestimates of the import
ance of these carnivores in some systems. As world fisheries begin to
experience serious declines, it is relevant to recognize that the carn
ivorous ''jellyfishes'' are ubiquitous and are thus opportunistically
positioned to utilize secondary production that is ordinarily consumed
by fish. (C) 1995 International Council for the Exploration of the Se
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