Parasites of Jellyfish in Eastern Australia

Abstract

Parasites are a major component of the Earth’s biota, yet are often overlooked and their importance underestimated. They affect nearly all organisms and can potentially regulate the populations of their hosts. Jellyfish are abundant members of the zooplankton community and are renowned for their ability to form large blooms. Jellyfish host a large diversity of parasites. Some of these parasites (e.g. hyperiid amphipods and parasitic anemones) use jellyfish as the sole host in their life cycle, whilst others (e.g. digenean trematodes and cestodes) use jellyfish as an intermediate host between other host organisms. There have been few ecological studies of jellyfish parasites (for example of spatial and temporal variation in parasite-host relationships) relative to other aspects of jellyfish biology. This may be partly attributable to the very small size of some parasites (e.g. digenean trematodes) and also to difficulties such as identifying larval parasite forms. However, with the advent of new technologies, such as molecular identification, and with diligent examination, these difficulties are able to be overcome. This thesis aims to identify jellyfish parasites using molecular and morphological techniques and elucidate their life cycles, examine spatial and temporal variation in jellyfish parasites and investigate the diversity and host specificity of the parasites of jellyfish in eastern Australia.