The 15th Conference of the parties concerned with the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), or the so-called "Washington Convention", that was established to conserve endangered wild habitats was held in Doha, Qatar from March 13th through to the 25th. A ban being placed on the international commercial trading of the Atlantic blue-fin tuna (described in Appendix I) being put on the agenda is probably still quite fresh in your minds.

About 40 thousand tons of blue-fin tuna is consumed in Japan every year: Half of that being imported Atlantic blue-fin tuna. The mass media such as newspapers played it somewhat up by trumpeting "We can no longer eat any tuna", which many people may have been interested in. The level of the natural resources of Atlantic blue-fin tuna was reported upon by the Fisheries Agency: They have decreased to a low level in the eastern Atlantic Ocean and remained the same at a low level in the western Atlantic Ocean; I must say that the state of them as a resource is really quite severe.

However, Japan's argument that "The recovery of the resource of the Atlantic tuna must be settled by the International Commission for the Conservation of Atlantic Tunas (ICCAT)" was supported by a number of countries and the proposal in Appendix I concerning the Atlantic blue-fin tuna therefore rejected. For your information the fishery management of tuna is performed by five different international committees as well as ICCAT: The Western and Central Pacific Fisheries Commission (WCPFC), the Indian Ocean Tuna Commission (IOTC), the Commission for the Conservation of Southern Bluefin Tuna (CCSBT), and the Inter-American Tropical Tuna Commission (IATTC). The respective committees determine the regulatory actions needed for the year in their region every year in managing them as a natural resource.

There probably still is room for managing them to be used as a measure; however, compliance with what was determined and then monitoring that compliance are both necessary for the recovery and sustainable use of a decreased natural resource.

In terms of the Atlantic blue-fin tuna issue taken up this time not only excessive catches of adult fishes but also the catches of seed fishes for use in aquaculture were pointed out. Japan the aquaculture of blue-fin tuna has been rapidly increasing: 4,500 tons were estimated to have been produced in 2008 but is expected to be over 10,000 tons in 2010. Naturally birthed young fish (Weight of 100 – 500 grams) are used as the seed (eggs, juvenile and young fishes used in aquaculture) for that aquaculture: They are housed in the cultural preserve after being caught and fed before finally being shipped out.

The amount of young fish that are caught this way is difficult to be precise about. The number of them that are eventually shipped as products is exact; however, some individuals when they are caught to be the seed or during the aquaculture process itself. Obviously the same amount of them is not shipped as are caught (number of seeds), and as a matter of course their supply as a natural resources would be affected if the catch of seeds for aquaculture were to become excessive. In fact, depending on natural young fish only as the seed supply for aquaculture would threaten them as a natural resource. This then makes a complete aquaculture system that would lead to the conservation of them as a natural resource even more essential.

A complete aquaculture system involves the following cycle: Artificially-incubated young fish (first generation) are raised to adult and their eggs collected, which are then used as the seed for aquaculture (second generation). This allows for aquaculture to take place without affecting the natural source at all. Kinki University succeeded in the complete aquaculture of the blue-fin tuna in 2002: The mass media claimed that they shipped over 30 thousand aqua-cultured seed fish this year. And while that number is too small for the number of seed fish currently required in the aquaculture of blue-fin tunas in Japan it is expected to increase in the future.

A similar topic involving eels is currently very hot in the field of complete aquaculture. The Fisheries Research Agency that I belong to has succeeded in the complete aquaculture of eels, something we have been addressing for some years now, in a global first. We officially announced the results in April. In addition to the recent decrease in the natural resource of eels the catch of the natural aqua-cultured seed fish (glass eels) this season in Japan has also drastically dropped by several dozen percent when compared to last season. Many people are now worried that they will no longer find eating eels quite as easy as before.

A decrease in the natural resource of eels in Europe is also rather severe: The proposal published in Appendix II was accepted at the CITES member conference in 2007 and eels have not been commercially dealt in without the permission of the exporting countries since 2009. There are several hypotheses on the cause of the decrease in the natural resource eels, but one that is undeniable is that it is a result of the increased catch of glass eels. Hence, in spite of the success of the complete aquaculture of eels the mass production of glass eels will still take some time yet, but mass production will definitely contribute to the conservation of the natural resource of eels if possible.

Several dozen types of fish are aqua-cultured in Japan. With freshwater fish except eels the seed fish for aquaculture can only be produced using artificial seeds through complete aquaculture and with saltwater fish only possible with flounder, Japanese red sea bream, and tiger puffer fish. The complete aquaculture of amberjack (Japanese amberjack and the greater amberjack), of which the amount produced in aquaculture is the largest in Japan, has been achieved; however, the seed fish for that aquaculture depends 100% on natural fish. There are still many issues to be solved with many types of fish before healthy artificial seed fish can be mass-produced to replace those caught naturally. When an abundance of a natural resource exists there is no problem; however, there is always the danger that a resource may end up like the Atlantic blue-fin tuna or eel.

Striking a good balance between the conservation of a natural resource and aquaculture is essential in developing the technology to mass produce artificial seed fish in complete aquaculture in addition to the establishment of the complete aquaculture technology itself.

Chinese / French / Japanese