|Aquaculture health training trip to Western Australia|
|Tuesday, 09 August 2011 10:47|
by Rarahu David
In 2008, following a series of exchanges with Western Australia’s Department of Fisheries Animal Health Laboratory (FHL), the Biotechnical and Pearl Quality Laboratory (LBQP) of the French Research Institute for Exploration of the Sea (IFREMER), and the Pearl Oyster Department (PRL), Dr Brian Jones and his colleague, Dr Fran Stephens, visited the PRL-IFREMER-SPE (French Polynesia’s Fisheries Department) research station in Vairao, Tahiti. This visit allowed useful exchanges about diseases at pearl oyster farms but also about shrimp and fish diseases. FHL is, in fact, in charge of diagnosing aquatic animal diseases (except for mammals) in the state of Western Australia, and Dr Jones, the lab’s head pathologist, is an internationally known aquatic disease researcher.
In order to further their training in specific diagnostic techniques for the marine setting, particularly in microbiology and histology, FHL and SPE jointly arranged to have FHL host an SPE agent (Rarahu David, head of the Health Programme for Non-Pearl-Oyster Aquaculture Facilities) and an IFREMER agent (Pevatunoa Levy, head of histology at LBQP) for two weeks in September 2010.
The trip provided an opportunity to review the information gathered for an histopathological atlas dedicated to the species Platax orbicularis, currently in draft. This project, initiated in Tahiti, will benefit from the guidance of Dr Jones.
Pevatunoa Levy received training in the histological techniques used at FHL, particularly the use of decalcification solutions (to soften bones and scales before samples are processed).
At the same time, Rarahu David was hosted by the microbiology laboratory of Dr Nicky B. Buller (author of Bacteria from fish and other aquatic animals: A practical identification manual, 2004). Dr Buller was trained in the various diagnostic techniques routinely used in that lab to identify bacteria that infect marine organisms. The lab carries out about 15 biochemical and enzyme assays similar to those used in Tahiti. Dr Buller trained Rarahu David in how to conduct various microbiological diagnostic tests (methodology, growth on specific culture mediums) and introduced her to a wide range of pathogenic bacteria that could pose a threat to the Paraha peue aquaculture facilities in Tahiti. A photo database was created to facilitate implementation of diagnostics in French Polynesia.
A trip was organised to visit the Cone Bay fish farm (http://www.marineproduce.com/barramundi.html). This farm, located in northwestern Australia, raises barramundi or Some of the eggs produced in Darwin are sent to a hatchery in Fremantle (near Perth), while the rest are raised in Darwin. Once the eggs have reached the juvenile stage, the fish produced in Darwin and Fremantle are transported by truck and then shipped to the Cone Bay site. An acclimation phase takes places in a land-based pond at the Cone Bay farm on Turtle Island. Once fish fry can eat 2 mm-sized pellets, they are transferred to nursery cages at sea using fish pumps. They are fed twice a day by hand or with a pellet gun. Each cage is cleaned systematically every month. Metal mesh keeps out marine predators (e.g. crocodiles and sharks) and nets above the cages keep out flying predators (birds).
Currently, samples are taken every month in all of the cages. In order to limit the handling of animals, video systems are being tested to replace sampling (by estimating the weight of filmed specimens). Aqui-S is used to anaesthetise the fish during sampling. During our visit, we were able to watch and take part in routine sampling by FHL in Perth. For each fish sampled, fresh gill and skin conditions are checked, and blood samples are taken while the fish is still alive. Once they are dead, fish are dissected to check the various organs in the internal cavity and to take histological samples (preserved in 10% formalin). Bacteriological samples are also taken from external wounds and internal organs (digestive tube) by using a system that allows the samples (live microorganisms) to be kept alive until they are cultured in the lab several days later.
On the way back, in the outskirts of Broome, we visited a Pinctada maxima hatchery (Paspaley Pearl Hatcheries Pty Ltd). Bryan Webster, the hatchery director, took us around the entire facility, which produces 40 million spat per cycle and has very strict hygiene measures and uses no antibiotics.
A third visit was arranged to the Australian Centre for Applied Aquaculture Research (ACAAR), a research centre for aquaculture based in Fremantle, Australia. ACAAR has a hatchery that supplies barramundi fry to the Cone Bay farm. It works with several other species, including Seriola lalandi, Argyrosomus japonicus, Pagrus auratus and Acanthopagrus butcheri. The facility offers various degreess in the area of aquaculture but also acts as consultant for aquaculture companies.
All of these instructive visits and meetings have allowed us to continue to improve the diagnostic and preventative techniques used in French Polynesian aquaculture facilities and to pursue exchanges on the topic with FHL and collaboration on the Paraha peue (Platax orbicularis) histopathological atlas.
This trip was made possible, in part, by financial support from SPC and the Australian government.
We would like acknowledge everyone who has contributed to the success of this trip, particularly those in Australia: Dr Brian Jones, Dr Fran Stephens, Dr Nicky B. Buller, and Daryn Payne for the welcome to the Cone Bay farm on Turtle Island.
 See http://www.challenger.wa.edu.au/Workingwithindustry/wamaritimetrainingcentrefremantle/Pages/AquacultureTraining.aspx
 See http://www.challenger.wa.edu.au/Workingwithindustry/acaar/Pages/ConsultingTrainingServices.aspx