Workshop to facilitate epidemiological analysis of unexplained mortality of South Australian Pacific Oyster

Funded Activity Summary

For at least the last 12 years SA growers have noticed unexplained mortality of Pacific Oysters. Tests for Pacific Oyster Mortality Syndrome (OHSV-1uvar) have come up negative each time.

The mortality was first documented in Smokey Bay and is now documented in all the major producing Bays in South Australia, including Coffins Bay, Smoky Bay, Cowell and Ceduna (Denial Bay). Mortality rates have been increasing over time. Losses of between 5-20% each year which equates to between $1.8-$7 million per annum.

Mortalities are generally associated with seasonal temperature related stress in the animals. The timing of the mortalities varies from year to year within specific bays. Mortlaities do not follow a geographical distribution with some sites more affected than others. Anacodatal advice from growers indicates that sites with slower growth rates don’t suffer as badly has highly productivity bays.

In recent years, mortalities have been experienced in the major producing bays. Anacdotal adivce from growers indicates that mortality is particularly in smaller to medium size oysters, but mortality is also occuring in mature stock.

There does seem to be a genetic link to the mortality with anacdotal reports of 100 % mortality of certain “batches”. Given this link the breeding program is breeding for resistance to these unexplained mortality events. Susceptibility varies depending on the family line.

In response some growers are lifting the height of the oysters which reduces the mortlaity rate but slows the growth rate and increases the growout time. There is concerm within the industry that this is not an economically viable solution in the long term.

Research has been proposed to investigate unexpained mortality however industry are supportive of an epidemiological analysis of exisiting data and knowledge to narrow the likely causes so that any future research is focused on likely causes.


Objectives:
1. Bring together growers and epidemiologists to define, describe and quantify the scope of unexplained mortality of Pacific Oysters in South Australia
2. Develop and test range of hypothetical causes of the mortalities based on best available information and expertise
3. Identify any gaps in the knowledge or expertise required to test the hypothetical causes
4. Refine and seek agreement on a future Research and Development plan that addresses unexplained Pacific Oyster mortality in South Australia

Funded Activity Details

Start Date: 17-09-2012

End Date: 01-04-2013

Funding Scheme: Funding Scheme not available

Funding Amount: $36,000.00

Funder: Fisheries Research and Development Corporation

Research Topics

ANZSRC Field of Research (FoR)

There are no FoR codes available for this funding activity

ANZSRC Socio-Economic Objective (SEO)

There are no SEO codes available for this funding activity

Other Keywords

Disease | Mortality | Workshop

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