Closing the tuna life cycle and creating more sustainable feeds are both needed to ensure the future of tuna production and conservation, according to Daniel Benetti, University of Miami, during a presentation at Aquaculture 2016 in Las Vegas, USA.

Ranching of Pacific bluefin, Atlantic bluefin, Southern bluefin and yellowfin tuna has increased in the past few years, particularly in the Mediterranean, west coast of the US, Australia, Mexico and Japan. These are first caught at sea as juveniles then transferred to a towing cage and on to a fattening farm. The fish are fed on wild caught sardines, mackerel or pilchards.

Progress in fattening operations has been limited, with only small improvements in management and the reduction of mortalities. As ranching still relies on wild catch for both production and feed, the line between aquaculture and fishing remains blurred.

However, in Japan, the farming of Bluefin tuna is progressing and the life cycle has been closed. Dr Benetti explained that it was hoped the same could be achieved in the near future for other tuna species such as bigeye and blackfin.

Blackfin tuna, as a smaller species, might be suitable for land-based facilities and has potential as a sashimi-grade fish.

Much more research is needed to improve larval survival rates, which are still below one per cent and the development of sustainable feeds remains an area of particular concern.

Source: Lucy Towers, TheFishSite. Read the full article here.