Survival and growth rate of ranched greenlip abalone off South Australia
SARDI Food Safety and Innovation
OGA are seeking to establish the viability of commercial greenlip abalone ranching operations near Port Lincoln in South Australia. A critical component of this process is site suitability evaluation and developing stakeholder support through R&D to demonstrate the effectiveness of greenlip abalone ranching in this untested location. Comparisons of potential ranching sites by an independent scientific institute (South Australian Research and Development Institute; SARDI) will provide reputable and objective information that can be used during an application for a commercial aquaculture lease. The project will also address a number of unresolved questions relating to the environmental conditions that influence greenlip abalone ranching and greenlip abalone biology across temperate Australia. As the selected abalone ranching locations are near commercially-fished wild populations, monitoring and controlling risks to these adjacent wild stocks is also required. Two key risks have been identified. The first risk is the potential for the ranched abalone to interact genetically with the wild stocks through either spawning or escapees. Thus, maturity status and escapement will be monitored. The second risk is for the elevated total greenlip biomass to result in a change in Perkinsus prevalence and expression of both the ranched and wild stocks. Thorny Passage is an area where abalone, particularly blacklip, have a high prevalence and intensity of Perkinsus olseni infection (O’Donoghue et al. 1991; Lester and Hayward 2005). An outbreak of P. olseni at Thorny Passage in 1996 necessitated a temporary 12% reduction in blacklip abalone quota for the Western Zone Abalone fishery (Nobes et al. 2004). Ranched abalone in the Thorny passage area would be constantly exposed to P. olseni infection with subsequent risks of stock mortality, morbidity and rejection at the processor or in markets, and these risks are likely to be exacerbated because hatchery reared stock may be naïve to P. olseni infection. Thus, perkinus will be monitored in both ranched and wild abalone (prior to – ranched; during – ranched and wild) during the project.
1. Quantify rates of survival and growth of greenlip abalone at sea ranches in South Australia;
2. Quantify the influence of abiotic (i.e. tide, swell, temperature) and biotic (i.e. feed availability, predator activity) conditions on survival and growth of greenlip abalone at sea ranches in South Australia;
3. Monitor the prevalence of the Perkinsus infection in greenlip abalone at sea ranches and in nearby wild populations
4. Determine the reproductive state of greenlip abalone from sea ranches;
5. Compare and contrast the survival and growth of greenlip abalone from sea ranches in South Australia with those from replicated studies in Western Australia.