Putting things the right way round: identification of upside-down jellyfish Cassiopea (Cnidaria: Scyphozoa) in Lake Macquarie

Presented by Claire Rowe
PhD Candidate, School of Life and Environmental Sciences, University of Sydney; and 2020/21 AMF/AMRI Postgraduate Award recipient, Marine Invertebrates, Australian Museum.

Cassiopea are unusual jellyfish, notable for their habit of lying “upside-down” – this means they lie ventral-side up on the benthos with their oral (feeding) arms facing upwards. Cassiopea are model examples of invasive species that have been historically confused because of taxonomic ambiguity. They can have significant economic and environmental consequences as jellyfish blooms are known to impact fisheries, tourism and trophic structures.

Historically, these jellyfish have had a northern tropical distribution, but in 2017 they were recorded in Lake Macquarie, New South Wales. Claire’s PhD focuses on the population dynamics of these jellyfish within temperate Lake Macquarie, including identifying which species is occurring through morphological and genetic comparisons to other populations.

This presentation outlines fieldwork in southern Queensland to collect Cassiopea from the type locality of one of the possible matching species. It will also explore the taxonomic ambiguity of Cassiopea, and results to date regarding the identification of Cassiopea within Lake Macquarie and possible vectors for its translocation there.