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Can commercial harvest of the long-spined sea urchin, Centrostephanus rodgersii, reduce the impact of destructive urchin grazing on macroalgae communities and associated fisheries?
conference contribution
posted on 2023-05-24, 17:42 authored by John KeaneJohn Keane, Craig MundyCraig Mundy, Olivia JohnsonOlivia Johnson, Scott LingScott LingRange extension of the long-spined sea urchin, Centrostephanus rodgersii, to south-eastern Tasmania has resulted in overgrazing of macroalgae habitats as far south as the Tasman Peninsula. The increasing loss of macroalgae and the formation of extensive barrens is threatening reef biodiversity as well as lucrative reef dependent fisheries such as abalone and rock lobster. A commercial fishery for long-spined urchin in Tasmania was established in 2008 and to date over 400 tonnes has been harvested. Dive surveys show that with increased fishing pressure there is a significant decline in the in size and age structure in urchin populations, as well as decreases in total biomass. Macroalgae recovery is occurring in some heavily fished areas, while barrens continue to expand in unfished areas. Analysis of boat-based GPS data logger and depth logger technologies used by commercial urchin and abalone divers indicates that >50% of urchin fishing activity overlaps spatially with abalone fishing activity. The extent of direct spatial overlap between these fisheries suggests there is good reason to expect that urchin fishing as currently observed could have direct benefits for the abalone fishery in terms of reducing abundance of urchins within or adjacent to key abalone fishing grounds.
Funding
Fisheries Research & Development Corporation
History
Publication title
Australian Society of FIsheries Biology ProgramPagination
60Department/School
Institute for Marine and Antarctic StudiesEvent title
Australian Society of FIsheries BiologyEvent Venue
Albany, WADate of Event (Start Date)
2017-07-22Date of Event (End Date)
2017-07-24Repository Status
- Restricted