Reproduction and survival of Phyllorhiza punctata (Cnidaria: Rhizostomeae) in a seasonally fluctuating salinity regime in Western Australia

Abstract

Although medusae of the scyphozoan Phyllorhiza punctata are abundant in the Swan-Canning estuary during summer, they are absent when surface waters are dominated by low-salinity runoff water following winter rains. In the laboratory, scyphistomae of P. punctata are shown to survive in conditions of temperature and salinity that occur in the estuary during winter in waters deeper than 5 m. It is postulated that areas of deep water provide a winter refuge for scyphistomae and that asexual production of both ciliary buds and ephyrae enables rapid growth of the P. punctata population in the spring of each year.