Asexual reproduction as prime mechanism in maintaining populations of Clytia gracilis in benthic littoral ecosystems.

JAUBET L.; GENZANO G. N.

MARINE BIOLOGY RESEARCH

TAYLOR & FRANCIS AS

Lugar: London; Año: 2010

1745-1000

Hydropolyps inhabiting temperate ecosystems show a marked seasonality could undergo regression as part of their life cycle. Clytia gracilis represents an example of sharp seasonality that occurs both in hydroids as well as in medusae. Epizoic colonies of Clytia gracilis attached to colonies of Pinauay crocea were monthly collected in the intertidal of Mar del Plata, Argentina (38°08´S-57°37´W) during low tide from February 2000 to January 2001. Abundance, seasonality and reproductive periods were analyzed. The hydroid reached a peak of abundance in the austral summer when scarce reproductive structures were observed in few colonies. A remarkable recession period was evident during the cold season, when the species was represented by few functional polyps but mainly by dormant coenosarcs in hidrocaulus and stolons. Clytia gracilis hydranths regenerated in the follow favorable seasons when a profuse asexual growth by stolonization was evidenced. Asexual propagation is proposed as the prime mechanism to maintain the hydroid populations.