Open Access

Underwater observations on the life cycle ofCorymorpha nutans (Hydrozoa)

  • A. Svoboda1
Helgoländer wissenschaftliche Meeresuntersuchungen24:BF01609506


1. Only one specimen ofCorymorpha nutans SARS has been found in the Mediterranean Sea near Naples until now.

2. A greater number of individuals of this species has been recorded from Rovinj, Northern Adriatic, since 1969 but only between January and May.

3. The individuals found measured between 2.5 and 20 cm in height. The hydranth's diameter reached a maximum of 20 cm.

4. The occurrence of big regenerating specimen led to the conclusion that the polyps live for several years and grow up annually from a summer resting stage.

5. Experiments with marked polyps conducted in the field and in the laboratory proved that no storage body is formed at the end of the season and that the polyps, therefore, live for one season only.

6. Regeneration of polyps which disintegrate because of senescence takes place in the same way as inCorymorpha palma or decapitated polyps.

7. The reasons for the different stages of regeneration found in the field are discussed, and the life cycle ofCorymorpha nutans in Northern seas considered.