Building bivalve hatchery production capacity in Vietnam and Australia

Scientific and commercial interest in the expansion of bivalve culture in Vietnam has led to rapid initial progress in developing hatchery skills and capacity. The hatchery at the National Marine Broodstock Centre (NMBC), Cat Ba has been built and is being equipped, while the first commercial batch of Pacific oysters was bred in August 2007 and distributed to grow-out facilities. This rapid development, in conjunction with delays in project commencement because of time taken for signature of the present MOU, has prevented Staff from NSW DPI providing advice on initial hatchery design (Objective 1.1). However, the design of the hatchery is such that it does not preclude the later installation and operation of advanced culture systems and to promote the optimal use of the new facilities, we have accelerated the training and demonstration program (Objective 1.2) and advanced the travel schedule for Australian staff to visit Cat Ba to provide culture advice.

To establish the knowledge base required for the selection of suitable species and their successful production, we have worked with Staff from RIA No1 to develop a list of potential molluscs of commercial interest and then refined that list to those of greatest interest; namely the oysters Crassostrea gigas & C. ariakensis, the clam, Luthlaria phillipinarum, and the pearl oyster, Pteria penguin. Vietnamese staff have started to gather information pertinent to the culture of these species, which will be compiled into a database (Objective 2.1). We have started compilation of a mollusc hatchery manual based on similar manuals for the culture of Sydney rock oysters and are incorporating experience already gathered in operating the hatchery at Cat Ba. To improve overall production performance we have identified a number of algal species likely to be of greatest nutritional value to the target species and have provided isolates of those species for culture at Cat Ba (Objective 1.3). Staff from NSW DPI is scheduled to visit Cat Ba in August to check algal production progress and assist in increasing algal culture reliability and output.
To aid the development of hatchery programs through an understanding of the reproductive behaviour of the species of interest, NSW DPI staff have visited Vietnam and demonstrated techniques (macroscopic, morphological and histological) for reproductive monitoring, provided data collection sheets and helped design experiments to monitor Pacific oyster reproductive condition across three sites and using two culture methods. This monitoring will commence when the current batch of Pacific oysters reach maturity. In the interim, NSW DPI staff have established protocols for routine oyster health monitoring and collecting oyster performance data that will provide useful information on growing Pacific oysters in Northern Vietnam (Objective 2.4).
The Australian based component of this program has begun and we have commenced assessments of non-chemical means for the production of triploid oysters (Objective 4.1). The impact of temperature shocks on the early developmental stages of oysters has been completed. In a series of trails, the effects of the timing, magnitude and duration of elevated temperatures on newly fertilised oyster eggs has been assessed in terms of percentage development and percentage triploidy. To complement this research, a pressure vessel has been purchased and is being shipped from the US to allow the impacts of pressure to be assessed and potentially used in conjunction with temperature for triploid induction.