MEPS 320:153-159(2006)  -  doi: 10.3354/meps320153

ABSTRACT: Changes in the prey composition of the stomachs of opportunistic-feeding fishes can provide information on various ocean-ecosystem dynamics. From 1981 to 2000, stomach samples of the spiny dogfish Squalus acanthias showed a major increase in the overall occurrence (and hence implied abundance) of Ctenophora, gelatinous zooplankton that range throughout the ecosystem. There have been a few such major increases in ctenophores in enclosed (e.g. Caspian Sea) and semi-enclosed (e.g. Mediterranean Sea) ecosystems, with concomitant significant effects on those ecosystems and the productivity of their fishery resources. We show the first such increases in ctenophores in an open ecosystem, persistent over 2 decades, with implications for the productivity of the fishery resources in any large marine ecosystem.

KEY WORDS: Gelatinous zooplankton · Large marine ecosystem · Global-scale perturbation · Ctenophore abundance · Spiny dogfish · Regime shift