Massive proliferations of scyphozoan jellyfish considerably affect human industries and irreversibly change food webs. Efforts to understand the role of jellyfish in marine ecosystems are based on a life cycle model described 200 years ago. According to this paradigm the pelagic medusae is considered seasonal and alternates with the benthic polyp stage from which it derives. However, we provide evidence that a) the occurrence of several species of medusae is not restricted to a season in the year, they overwinter, b) polyp- and medusa generations are neither temporally nor spatially separated, and c) "metagenesis" which is defined as the alternation between sexual and asexual generations does not always occur. Hence we recommend additions to the current model and argue that the scyphozoan life cycle should be considered multi-modal, rather than metagenetic. The implications of these findings for jellyfish proliferations, including possible consequences and associated environmental drivers, are discussed.
Bibliographical noteFunding Information:
We would like to thank Rodrigo Saavedra for providing information on sightings of C. plocamia (field and video) and for help in the field. Other helpers in the field and/or lab are thanked, including Ignacio Caceres, Viviana Villegas, Lissette Paredes and Camila Valdivia. We also thank Mike van Keulen, Martin Thiel and Jean-Baptiste Raina for helpful comments on an early version of the manuscript. This project has been funded by a FONDECYT-Grant (# 1100256) to JMR.