The Freshwater JellyfishCraspedacusta sowerbyi:a Summary of Its Life History, Ecology, and Distribution

Because most work with the freshwater jellyfish Craspedacusta sowerbyi has consisted of isolated collection records, published in a diverse array of journals, it is difficult to draw conclusions and generate testable hypotheses for future work. Here I compile and summarize the available information on the life history, ecology, and distribution of this unique freshwater invertebrate within the United States. The life cycle of C. sowerbyi contains both medusa and polyp stages, and although it has been collected primarily from artificial habitats (e.g., reservoirs), it has been found in both natural lentic and lotic habitats. Both polyps and medusae feed on a variety of prey types; however, because medusae are typically found at low densities, they probably do not influence zooplankton density. The distribution of C. sowerbyi appears to be concentrated in the Eastern United States, with collection records in the west limited to six states (California, Colorado, Nevada, Oklahoma, Oregon, and Texas). Overall, its presence has been documented in 31 states. Though the life cycle and distribution of C. sowerbyi have been relatively well described, substantial gaps still remain in our knowledge of the role of this jellyfish in freshwater communities.