The Comb Jelly Mnemiopsis Leidyi in the Black Sea

Abstract

Following its transportation in ballast waters, the western Atlantic ctenophore Mnemiopsis leidyi caused a striking damage to the ecosystem of the Black Sea in the early 1990s. The concentration of food Zooplankton and simultaneously catches of anchovy and other pelagic fishes sharply decreased during the peak levels of the ctenophore. There have been many studies on the distribution and physiology of this ctenophore in its new environment due to its substantial impact on the marine ecosystem. Later in mid 1990s its biomass was at moderate levels till the appearance of its predator, another ctenophore Beroe sp. in 1997. The predator decreased Mnemiopsis biomass to very low levels which was confirmed by both laboratory and field observations. Now Mnemiopsis is causing very similar problems in the Caspian Sea following its transport from the Black Sea.