It would be fair to say that the connotation of successful captive breeding programs for endangered species more readily conjure up images of the California condor, golden lion tamarin and even tigers.

However, research scientists at the Oceanographic Centre of the Spanish Institute of Oceanography (IEO) are attempting to implement this concept for the endangered Atlantic bluefin tuna. Indeed, this highly prized fish, native to both the western and eastern Atlantic Ocean, as well as the Mediterranean Sea, has already suffered extinctions in the Black Sea and Caspian Sea.

In this pioneering programme, a broodstock of around 60 individuals are housed in two floating cages 25m wide x 20m deep in the bay of El Gorguel. Up until recently domestication of this great species has proved difficult due to their great sensitivity and pelagic nature, being accustomed to an expansive and unobstructed open water environment. Initially, successful spawning could only be achieved through hormonally inducing the broodstock with GnRH implants. However, over the last two years spawning has begun spontaneously without the need for hormonal induction, signifying a significant step in the quest for the tuna to reach a degree of domestication.

While the depletion of natural populations from overfishing is being regulated by fishing quotas to limit its capture, it would seem that the potential for Atlantic bluefin tuna production via aquaculture, as is the case with species such as sea bass or salmon, could represent a viable option to reducing pressure on natural populations and contribute to recovery.