Science Network
May 21, 2012

Western Australia is now a part of the effort to reverse diminishing global tuna stocks.

Tuna poses many aquaculture challenges with a low survival rate in the larval rearing stage and slow maturation.

Dr Gavin Partridge, a Senior Research Scientist at Challenger Institute of Technology’s Australian Centre for Applied Aquaculture Research (ACAAR), has been working with institutes in the United States, Panama and Indonesia in order to find more sustainable tuna farming practices.

“We’ve collaborated with the University of Miami and the Inter-American Tropical Tuna Commission in Panama,” Dr Partridge says.

“We have been looking at ways to reduce the long life cycle of tuna and improve the survival of larval tuna for aquaculture purposes.

“Our main collaboration is with the Gondol Research Institute for Mariculture.  We’re helping them rebuild their brood stock population and get their fish spawning again.”

ACAAR’s work aims to take the global dependence away from wild tuna stocks by addressing farming and reproduction challenges, making them more viable for aquaculture.

“The aquaculture around tuna is based around catching tuna from the wild, fattening them up and selling them. This is not a sustainable practice given that global tuna stocks are in decline,” Dr Partridge says.

“Compared to other aquaculture species they’re very difficult, most farms will get less than one per cent survival through the larval rearing stage. Other aqua culture species reach 10 to 50 per cent survival.

“It’s because they’re an open ocean polyergic species, they’re biologically sophisticated—very different to other species that we’ve farmed.”

Tuna are also slow to mature, many tuna species are only able to breed when they are 8–10 years old.

“The breeding age is quite old for some species, bluefin tuna (Thunnus orientalis) don’t spawn until they’re 10 years old and at that stage they weigh 150kg and require expensive, specially built facilities,” says Dr Partridge.

He says his collaborative work is creating more efficient tuna aquaculture techniques.

“Everything we do is geared towards closing the life cycle and increasing survival rates of tuna larvae to a level where commercial hatchery production can be achieved,” he says.

Much of Dr Partridges work involves yellowfin tuna (Thunnus albacares).

He says it is a more versatile species and the research can be translated for use on other tuna species.

“One of the benefits of working with yellowfin tuna is they spawn at a much younger age and they spawn all year round, so we have constant access to eggs to study and practice our techniques.”

“The idea is the work we do with the yellowfin tuna will eventually benefit all tuna species,” says Dr Partridge.

Original source