Reproductive strategy of Beroe ovata (Ctenophora, Atentaculata, Beroida) -A new invader in the Black Sea

Factors affecting the egg production of Beroe ovata were experimentally stu died. Ctenophore clutch size increased with animal size and ranged from 40 eggs for small specimens to 5000-7000 eggs for individuals 80-120 mm long. The beginning of maturation was recorded for the ctenophores bigger than 30 -35 mm. Clutch size was directly influenced by the amount of ingested food. Starving animals produced no eggs. No influence of temperature on the dutc h size was indicated within the range 15-22 degreesC. Possible factors affe cting the eggs viability which varied in the experiments from 20 to 80% are discussed. In the autumn of 1999, the spawning period was observed in Sept ember-October with a maximum at the beginning of October. Concentration of the larvae in the near-shore zone amounted to more than 400 ind. m(-2). Off shore, their amount decreased and in the central part of the sea they were not found.