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Coast Professor Gets Tuna “In The Mood” For Reproduction

Some like the lights on, others prefer them dimmed. Some like it hot, some not.

When it comes to procreation, southern bluefin tuna are like the rest of us – they like the moment to be “just right”.

What constitutes “just right” always eluded those who have attempted to breed bluefin tuna in captivity – until now.

At Arno Bay, near Port Lincoln in South Australia, a team of researchers has successfully mimicked the natural conditions in the seas off Indonesia to produce what is believed to be the first spawning of captive southern bluefin tuna in the world.

Professor Abigail Elizur, one of a team of nine from the University of the Sunshine Coast involved in the project, said the researchers had to determine the specific ocean conditions then replicate them in a pool to encourage the tuna to spawn.

“It’s a whole range of conditions – light, temperature, density, how many other fish you have around, how many fish you have in a large group, different sized schools,” she said.

“We have to get the light and temperature right and mimic the environment conditions so the fish feel that it’s the right environment to spawn.

“It’s a very different environment in the sea to what we can create on land, and the tuna are already sensitive to handling.”

Prof Elizur paid tribute to Clean Seas Tuna chairman Hagen Stehr, who had brought together a collaborative team and invested heavily in the project for years, even airlifting tuna into tanks, in the dogged belief that the fish could spawn in captivity.

She said the spawning began in March and had so far produced 50 million fertilized eggs, compared to a smaller previous captive spawning where the spawn had died.

She could not elaborate on the exact conditions created to produce the successful captive spawning because of the potential commercial ramifications.

The captive spawning could revolutionize the tuna industry through commercial farming of the fish, she said.

“If you can grow them yourself, you obviously have a lot of control,” she said.

“You can control the numbers, when you have them, so it’s very significant.”

The project, supported by the Australian Seafood Research Cooperative Centre, has run over several years and involved about 100 researchers.

Prof Elizur’s work on the project helped earn her the USC Vice Chancellor’s Medal for Outstanding University Researcher for 2009, presented at the recent graduation ceremony.