Hatchery International

Features Research
Breeding for resistance to disease


April 29, 2014
By Erich Luening

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The Australian oyster industry continues its efforts to overcome the Pacific Oyster Mortality Syndrome (POMS) that has caused significant problems for the sector in recent years.

POMS is a recently identified disease of Pacific oysters (Crassostrea gigas) that continues to cause sudden and enormous mortalities on Australian oyster farms. The likely causative agent is a variant of oyster herpesvirus, OsHV-1: the same virus that has devastated Pacific oyster production in Europe and New Zealand.

The industry’s strategic plan to address this threat has three components: (1) The maintenance of quarantine barriers and control of stock movement; (2) identification of husbandry aspects that can mitigate the disease’s effects; and (3) genetic selection for disease resistance.

         Matt Cunningham, general manager of Australian Seafood Industries Pty Ltd’s hatchery-side of the program, said in a video a few weeks ago that last year’s trials have provided information justifying a continuation of efforts towards breeding a POMS-resistant oyster. In a brief statement from Tasmania, Cunningham said that his hatchery staff had just completed producing some 80 new oyster families for field trials.

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         “These are from our second-generation of POMS families,” Cunningham said. “The results will be worth watching for.”

         He explained that that breeding for POMS-resistance can be difficult, so a crucial part of the multi-unit program is being conducted through the Elizabeth Macarthur Agricultural Institute (EMAI is the NSW Department of Primary Industries Centre of Excellence for Animal and Plant Health) and will include efforts to develop a laboratory-based trial.

         “Researchers are having some success in this area,” Cunningham said, adding that they have been able to infect oysters with stored virus.

         Cunningham also referred to a 2013 field challenge ASI ran in the Georges River, NSW, using Year Class 2012 spat from pedigreed families from the ASI breeding population. Mortality rates ranged from 20-80%. Genetic differences were measured and these appear sufficient to warrant continuing work in this area.

Observations from this trial are also supported by largely anecdotal information from France and New Zealand. However, there is as yet insufficient knowledge to enable breeding for POMS-resistance to move to a fully operational phase.       

Cunningham also noted that the project hasn’t all been smooth sailing. Recently the virus has been causing serious mortalities in Port Stephens, which is used as a holding area for oysters en route to Georges River, and they are having to consider risk-mitigation measures for the project.


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