A vital step towards closed life cycle farming of the commercially valuable Atlantic Blue Fin Tuna (NBT) was achieved in the Adriatic farming sites of Kali Tuna, a Croatian tuna farming company and the laboratories of Aquaculture at Institute of Oceanography and Fisheries (IOF) in Split. Marine scientists at IOF have confirmed that gametogenesis was completed and a number of tuna eggs were spawned in cages off the coast of Croatia.
In the experiment over 800 pieces of brood stock were kept in a special cage since the spring of 2006. The fish spawned successfully in the cage during the early summer of 2009. Most of the eggs were released naturally into the water, whilst a number of eggs were collected and later successfully hatched in a Split-based laboratory.
During the past few years the future of the NBT has become bleak, with excessive catch of the coveted fish which claims up to $25(US) a pound on the Tsukiji fish market in Tokyo.
The key to sustainability in the farming of tuna is to domesticate the NBT by creating a ‘closed life cycle’ farming process, as previously has been done with salmon and other species. This process involves breeding the fish in captivity and growing it on underutilized, small pelagic fish. Scientists and tuna farmers in Europe, Japan and Australia have for years tried to achieve hatching in captivity, a task made especially difficult by the lack of knowledge of the mating habits of the tuna. Some success has been recorded to date, by Kinki University in Japan and Clean Seas Tuna in Australia, in each case in artificial, controlled environments.
“The fact that the captive tuna has spawned without hormones or human assistance makes this a unique event.” says Dr. Ivan Katavic, former assistant minister of fisheries in Croatia, currently the Head of Laboratory at the Institute of Oceanography and Fisheries. “Our project was designed to break the code of the NBT’s reproduction habits. We aimed to create a closed life cycle for the farming of the species and relieve the pressure on the existing fish in the world’s oceans. This result is a significant step in that direction. The combination of the farming techniques of Kali Tuna and the location of their cages are the key to our NBT breeds in captivity achievement. Kali Tuna grows its fish for a longer period than most other farms. The combination of good husbandry and unique site conditions allows Kali Tuna to meet physiological requirements of brood stock to complete reproductive cycle in captivity.”
Oli Valur Steindorsson, is the Executive Chairman of Kali Tuna. Born in the fishing village of Akranes in Iceland, Steindorsson spent a year in Tokyo as an exchange student, studying the Japanese language and culture. He entered the Japanese seafood business as an intern at the age of 17 and established his own seafood trading company a decade later. Steindorsson stated, “We maintain a clear focus on creating a sustainable, closed lifecycle farming process, producing top of the line, healthy seafood with the least environmental impact possible. The natural circumstance of the event furthermore creates a hope of an extremely cost effective way to farm the fish.”
Further reading, including pictures and biographies of Dr. Katavic and Mr. Steindorsson: www.kali-tuna.com.