Risk factors and management strategies associated with summer mortality in Australian abalone

Greenlip abalone and hybrid abalone are grown in southern Australia. During grow-out, abalone are exposed to water temperatures that range from 10˚C during winter in Tasmania to 25˚C during summer in South Australia. When water temperatures exceed 22˚C, mortalities up to 50% have been reported for cultured greenlip abalone as well as wild abalone. High mortality during warm summer water temperatures has been termed ‘summer mortality’ but is not a well-defined condition. To date notifiable and infectious disease agents have been ruled out, although this information has not been summarised and documented. Given that good evidence of the diseases status of Australian farms is crucial in negotiating with countries to which abalone are exported this investment will develop a definition of summer mortality, investigate current and retrospective mortality events and comprehensively rule out the influence of primary pathogens and infectious agents in both control and impacted populations.