The Clean Seas Tuna Limited kingfish breeding experiment has been a success, paving the way for the world's first land-based tuna breeding venture.
Clean Seas Tuna Limited owned by tuna baron Hagen Stehr began breeding kingfish on land as a trial in its aim to breed 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. Each day the project is one step closer with the construction of a 50-meter by 30-metre shed, which will house the second-largest fish water tank in the world. Twelve to 15 brood stock will live in the tank in three million liters of water.
Clean Seas Hatchery manager Morten Deichmann said breeding tuna was basically the same as kingfish but on a much larger scale.
â€The kingfish was thought of as a good model for the tuna because it is a pelagic fish,†Mr. Deichmann said.
Kingfish are caught from the wild, put into a quarantine tank, checked whether male or female and then four males and three females are transferred to one of the brood stock tanks.
The tanks are in separate rooms and are temperature and light controlled to simulate a natural environment.
Assistant hatchery manager Adrian McIntyre said light was controlled to make the days longer and temperature changed to make the water warmer to “trick the fish into thinking it is summerâ€. With the right environment the fish will spawn.
During the artificial summer period Mr. McIntyre said the fish produced 350,000 fertilized eggs per liter, with five liters produced a day for about three months.
The egg survival rate is about 15 per cent and those that survive are then put into very controlled conditions.
Everything has to be perfect, from the right amount of algae to specialized feed. When they are three kilograms the kingfish are transferred to the ocean.
Last year 360,000 kingfish were bred and put in cages at sea and Mr. McIntyre said this year they hoped to double that amount.
The next step is breeding southern bluefin tuna. â€We are very confident we can do the same for tuna,†Mr. Deichmann said.
The challenge with tuna is that it is a very fast swimming fish, grows at double the speed of kingfish and is less flexible, hence the huge tanks the 12 to 15 brood stock will live in.
Control of the light and temperature to create a comfortable environment for the fish is considered vital.
But Mr. Deichmann said the company was confident because they had done their research, the workers had a wealth of knowledge and there had been successful sea-based tuna breeding programs in other countries.
The Japanese successfully bred the Pacific Bluefin and there have been other projects elsewhere in the world - however the
â€Our first goal is just to produce it,†he said.
Mr. Deichmann said it was taking the industry to the next level to “complete the life cycle and be able to produce them to supply and demandâ€.