Environmental forcing in early life stages of the scyphozoan jellyfish Rhizostoma luteum

Abstract

It is important to understand the role of early life stages in the formation of jellyfish outbreaks, whether they are cyclic or in response to climate change, and it has been neglected until recently. The aim of this study was to determine the response to environmental forcing in the early life stages of the scyphozoan jellyfish Rhizostoma luteum. Laboratory experiments were carried out to examine the effects of different temperature and salinity conditions on planula settlement, scyphistoma development, podocyst production, ephyra liberation and development until the metaephyra stage. The results show that the planuae were highly resilient to a wide thermal and salinity window and they settled faster in warmer conditions. However, the scyphistomae showed physiological stress in the warmest (28 °C) and saltiest (38) treatments. Asexual propagation and ephyra growth were greater at mid temperature (23 °C) and in hyposaline (24) conditions. Their ability to grow in hyposaline conditions raises the possibility that some or all reproductive stages may occur in estuaries or other brackish environments. The ongoing ocean warming and the decrease in rainfall are discussed to explore the implications in this jellyfish population dynamics.