Focal region: Victoria, Australia
Focal ecosystem: Rocky reefs/kelp forests and seagrass meadows

Overabundant local and range-expanding native sea urchins present an ever-increasing threat to marine  biodiversity in Victoria. Overgrazing by purple sea urchins is a significant threat to reef and seagrass biodiversity in Port Phillip Bay and Nooramunga. Range expansion of the black-spined sea urchin invading from NSW into eastern Victoria is resulting in extensive kelp bed loss with growing concerns of further spread into central and western Victoria. Currently there is little understanding of the scale of the problem, what management actions are most appropriate and where they should be targeted. This project will collate information on urchin biomass hotspots and the scale of barrens state-wide, use this information to inform population dynamics models of both species to identify sources and dispersal/invasion pathways, develop standard methods for culling and monitoring and implement a state-wide culling program.

Marine Protected Areas (MPAs) (Point Cooke, Jawbone, Ricketts Point, Nooramunga, Beware Reef and Cape Howe) have been prioritised over other locations for the culling program as these areas have already been identified as having significant natural value and have minimal disturbances from other sources. In addition, in many of these MPAs the barrens are only discrete patches, therefore natural recovery can be expected to be greater than in areas of extensive barrens. Moreover, immediate action is needed to prevent expansion or new barren formation. The data from this project will be used to develop a decision-support framework, including scenario testing and estimating the cost benefits of different urchin management approaches and their site-specific suitability for each location, to help inform an urchin management plan for the state of Victoria.