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Breeding Bluefin Tuna In Captivity

Breeding & genetics Technology & equipment Politics +2 more

SPAIN - A team of EU-funded researchers from Spain have, for the second year running, successfully harnessed bluefin tuna (BFT) spawn without using hormonal induction. This means the team will be able to closely study the reproductive habits of this endangered species in captivity.

The work was carried out as part of the SELFDOTT project ('From capture based to SELF-sustained aquaculture and Domestication Of bluefin tuna, Thunnus tynnus'), which received a boost of 2.98 million euros under the 'Food, agriculture and fisheries, and biotechnology' Theme of the EU's Seventh Framework Programme (FP7).

The team, from the Murcian Oceanographic Centre, part of the Spanish Institute of Oceanography (IEO), is hoping that this year's eggs will prove luckier than their previous yields, which had low success rates as the BFT only survived on average for between 73 and 110 days.

This is the third year of the project and the second in which the team has obtained the eggs by natural means. In 2009 the first spawnings were obtained after hormonally inducing the broodstock with GnRH implants and in 2010 the spawning were obtained spontaneously without the need for hormonal induction.

The fact that the spawning has now been obtained naturally two years in a row indicates that the 60-strong broodstock has reached a very important degree of domestication as a result of their four year stay in two floating cages 25 m wide by 20 m deep in the bay of El Gorguel (Cartagena). These massive spawnings can even be as large as over 10 million eggs in a single day.

BFT has been a crucial part of the Mediterranean diet for thousands of years but the effects of overfishing has led to the setting up of quotas to preserve the species.

But by using artificial aquaculture techniques, a process of farming fish and other natural, water-related produce in controlled environments rather than harnessing them from the ocean and sea, the quantities of BFT required by consumers can be achieved, relieving some of the pressure on endangered natural populations and contributing to the eventual recuperation of the species in the wild.

Species such as sea bream, sea bass, turbot and salmon are currently widely produced using aquaculture techniques.

Now the team plans to develop new techniques that can help its members study embryonic and larval development and the BFT biological cycle, which would hopefully lead to the production of fry (tuna offspring) through aquaculture techniques independent from natural populations.

At the same time, suitable and environmentally performing feeds for the grow out of BFT will be developed, thus reducing or eliminating the practice of raw fish importation and feeding by the fattening industry.

These new stages of the research will be carried out with the 13 other SELFDOTT partners, made up of government bodies, research institutes and industry organisations from France, Germany, Greece, Israel, Italy, Malta, Norway and Spain.

Further Reading

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