Distribution and abundance of moon jellyfish (Aurelia aurita) and its zooplankton food in the Black Sea

The distribution of moon jellyfish (Aurelia aurita Linnaeus, 1758) in the B lack Sea was determined from plankton samples collected above the anoxic zo ne (maximum depth 200 m) in the summer, winter and spring during 1991-1995. Distribution was patchy. Average biomass ranged from 98 to 380 g m(-2), an d abundance varied from 2 to 14 individuals m(-2). Biomass and abundance pe aked in late spring and summer. The distribution was correlated with hydrog raphic features in the Black Sea, with higher concentrations occurring at t he peripheries of anticyclonic eddies. Centers of the two main cyclonic gyr es generally had a low biomass of A. aurita. From July 1992 to March 1995, the populations were largely concentrated in offshore regions. A. aurita we re confined to the upper part of the mixed layer. Smaller A. aurita (less t han or equal to1 cm) were present in early spring (March), and individuals reached maximum size in the summer. Release of the epyhrae occurred in spri ng on the northwestern shelf of the sea when the seawater temperature was 1 1-12 degreesC. Microscopic analysis of stomach contents showed that copepod s and mollusks form their main diet.