Angasi oysters - research information sheet

The Angasi oyster (Ostrea angasi) also commonly known as Flat oysters occur naturally along the entire coast of NSW and extend into southern Queensland as well as into all the southern states and Western Australia.

Trial hatchery production of seed oysters by NSW DPI and pilot farming of this oyster over the past five years is helping the existing Sydney rock oyster industry to develop a new product line suitable for both local consumption and for export especially into Asia and Europe.

For each of the past five years several (3 to 5) million seed Angasi oysters were produced by scientists at the Port Stephens Fisheries Centre. These small 0.5 mm but cheap ex-hatchery spat were supplied to oyster farmers that had each set up field nurseries at sites in Pambula Lake, Merimbula, Bermagui, Narooma, Batemans Bay, Port Stephens and Yamba. Farmers on the NSW south coast have now established small scale hatcheries to meet their own needs.

As part of the NSW Government’s continued commitment to aquaculture development, NSW Fisheries is providing these farmers with advice on design, assembly and operation of field nursery equipment as well as advice on care and handling of stock. In most cases, results achieved by the farmers using pump ashore field nurseries have exceeded expectations. Growth rate and survival of spat on a diet of wild phyto-plankton have been far superior to that achieved in previous years with hatchery spat fed cultured micro-algae.

Experience gained during four years (1997 to 2000) of trial farming of Angasi oysters on the south and central coasts was reviewed in a special workshop hosted by NSW DPI in March 2000. Results showed that market size is achieved in 18 to 24 months when the Angasi oysters are grown on existing intertidal rack and tray leases developed for Sydney rock oysters and even faster if grown in suspended culture on deeper sub-tidal leases.

The trials also showed local and interstate market prices for Angasi oysters are considerably higher ($8 to $10 dozen) than that of both Sydney rock and Pacific oysters. Much of these results and an array of other useful information on farming of Angasi oysters including major potential risks, such as those posed by the disease Bonamia, are summarised in a published proceedings of the 2000 workshop that can be purchased from the Department.

More recent developments in trial farming, processing and marketing of Angasi oysters were reviewed in follow-up industry workshops hosted by NSW DPI in March 2001 and February 2002. These workshops led to the formation of the NSW Angasi oyster farmers group. (Contacts: David Maidment, Tel - 02 4476 7758 and or Ray Tynan, Tel - 02 6495 6398) and have set continuing research and development priorities. Priorities include the development of a new molecular test for diagnosing Bonomia, a disease that has decimated stocks of Angasi oysters throughout the world. Prelimanary surveys of five south coast estuaries have confirmed the presence of Bonamia in NSW. Other high priority research and development topics identified are a genetics survey of wild Angasi oysters, post harvest handling and processing of live and half shell product.