Photograph: courtesy Dr Ian Whittington

Research team:

Dr Ian Whittington (School of Molecular & Microbial Sciences), Dr Ingo Ernst (School of Molecular & Microbial Sciences), Peter Cook (School of Molecular & Microbial Sciences), Dr Clive Talbot (Nutreco Aquaculture Research Centre, Stavanger, Norway), Dr Serge Corneillie (Nutreco Aquaculture Japan, Fukuoka, Japan)

Funding:

2000?2001 Industry funds from Nutreco Aquaculture Japan (~$175,000)

Email/Web link:

i.whittington@mailbox.uq.edu.au www.nutreco.com

Faculty of Biological & Chemical Sciences

Two University of Queensland researchers in collaboration with overseas industry partners are helping Japanese aquaculture farmers improve management and husbandry of a popular Japanese eating fish.

Drs Ian Whittington and Ingo Ernst of UQ's School of Molecular and Microbial Sciences are studying the basic biology of a common parasite of farmed Japanese table-fish to reduce fish mortality.

Dr Whittington said the project was important financially and culturally, because seafood formed such a large part of the Japanese diet.

"An average Japanese person consumes 80kg of fish a year, with the largest aquaculture species being the Japanese yellowtail, a fish with good eating qualities popular for sushi and sashimi," he said.

"However, this fish has about a 20 percent mortality rate from various diseases such as parasites, which do not affect humans but can prove fatal to the fish.

"As about 140,000 tonnes of yellowtail a year find their way on to the Japanese market at a wholesale value of AUS$2.4 billion, any techniques to improve management could be very important financially to the Japanese fin-fish aquaculture industry."

Dr Whittington is an expert on monogeneans, tiny parasitic flatworms which live on the gills, fins and skin of fish. His research interests include the basic biology of monogeneans, and also developing powerful marine glues from the parasites.

Commercial partner Nutreco Aquaculture Japan conducted a literature search to identify the foremost international expert on monogeneans, and came up with Dr Whittington. Dr Ernst last year completed a PhD on parasites co-supervised by Dr Whittington.

The firm is sponsoring a two-year, $150,000 project by Dr Whittington and Dr Ernst in the southern Japanese islands of Shikoku and Kyushu, where a large aquaculture industry for yellowtail flourishes.

"It's a happy coincidence of interests. The company lacked the knowledge of the biology of the parasite while this project gives us an application for our expertise," Dr Whittington said.

Dr Ernst said the parasites could spread rapidly in farmed populations where large numbers of fish were captive inside floating sea-cages in small areas. The current methodology used by farmers to overcome the problem was to treat the fish in freshwater baths. Although the treatment is effective, it is labour-intensive, expensive and stresses the fish.

Dr Ernst made three trips to Japan last year to meet with farmers and accumulate information on the culture conditions for the fish, algal growth on cages, water temperatures, parasite/host interactions and other factors. He is developing a computer model to more accurately predict the growth of parasite populations under different scenarios.

In 2001, Dr Ernst spent two periods of approximately three months each gathering extensive data about the parasite and its relationship with the fish-host. An honours student, Peter Cook, will also be studying in detail the fate of the parasites' eggs and whether there are methods to reduce re-infection rates by improving husbandry techniques used by farmers. A critical aspect of the study is close liaison with farmers.

Nutreco Aquaculture Japan Representative Managing Director Joep Kleine Staarman said the company was impressed with the practical approach Drs Whittington and Ernst were taking to the parasite problems of Japanese fish.

"The way they interact with the Japanese farmers while collecting information and samples suggests there are no cultural differences between Australia and Japan especially when they present their findings to the farmers and give advice on how to manage the farms," Mr Staarman said.

"So far, information has been collected mainly on the parasites' biology but with this better understanding, we are confident of solutions. However, this may take time. We look forward to a continued research collaboration with UQ over coming years and eventually to solve or diminish the parasite problems in warm-water fish."

Events that occurred in South Australia at the end of 2000 and early in 2001 means that this research program now has a strong Australian focus, according to Dr Whittington.

"The culture of kingfish, closely related to yellowtail (they are all Seriola species, related to trevally), in floating sea-cages off the coast of rural and regional South Australia is an emergent industry," he said.

"However, monogenean parasites like the species that infect Japanese yellowtail also threaten the future viability of the fledgling kingfish industry down south."

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