April 6, 2006

 

Company hopes to float land-based tuna breeding venture

 

 

The success of the Clean Seas Tuna kingfish breeding experiment has now set the stage for the world's first land-based tuna breeding venture.

 

Clean Seas Tuna Limited began breeding kingfish as a prelude to breeding southern bluefin tuna in tanks on land.

 

The company plans to introduce tuna brood stock into a holding tank this August and could be breeding southern bluefin tuna as early as 2007.

 

A 50-metre by 30-metre tank will house 12 to 15 brood stock in three million litres of water.

 

Clean Seas Hatchery manager Morten Deichmann said breeding tuna was similar to breeding kingfish but on a much larger scale.

 

The kingfish was thought of as a good model for tuna because it lives in the open ocean, Deichmann said.

 

Kingfish are caught from the wild and are raised in brood stock tanks whose temperatures and light conditions are controlled to simulate conditions in the wild.

 

Assistant hatchery manager Adrian McIntyre said light was controlled to make the days longer and temperature changed to make the water warmer to make the fish think it is summer, the spawning season.

 

During the artificial summer period, each fish produces 1.7 million eggs a day for about three months. 15 percent of the eggs survive and they are put into pools with tightly controlled conditions.

 

Last year, 360,000 kingfish were bred and put in cages at sea and McIntyre said the figure may double this year.

 

The company is hoping it can do the same for southern bluefin tuna.

 

However, tuna is a very active fish and has double the growth rate of kingfish, hence the need for huge tanks.

 

The Japanese successfully bred the Pacific Bluefin and there have been other similar projects elsewhere in the world. However, the Clean Seas project is a first because the breeding is taking place on land.