Aquacultuer for Sustainable Tuna and Aquatic Resources

Aquaculture enable to produce fishes with more stably than catching fisheries, which are affected by fluctuations in natural resources. In fact, aquaculture production has increased dramatically since the late 1980s, whether global fisheries production has remained largely unchanged at the same period.
(See natural resource → Fishery procuction)

What's aquaculture

In dictionary terms, aquaculture in a broad sense, is defined as "the artificial breeding of fish, shellfish, seaweed, etc. using fish tanks, baskets, ropes, ponds, etc".

Aquaculture in a broad sense includes

- aquaculture to grow catched fry (juenile fishes) or eggs in nature upto adult fishes (most popular),

- aquaculture to grow catched adult fishes up with more bigger and fattier fishes (termed farm-fatting),

- prepair eggs in arificial condition and culture to grow them upto adoult fishes (and get next eggs) (termed complete aquaculture),

and so on.

Regarding tuna aquaculture, in Japan, tuna is generally raised from fry to adults, with 200 to 800 g natural seedlings being reared to 30 to 80 kg for a long period of 2 to 3 years before shipping. Overseas, on the other hand, adult fish weighing 20 to 100 kg without little fat are kept in fish tanks for a short period of about 2 to 6 months to increase the tuna's fatty parts, thereby increasing its market value, and then shipped.

Complete Aquaculture

The "complete aquaculture” is a type of aquaculture.

The critical difference between complete aquaculture and other aquaculturea is the original fish materials for aquacultutre. In aquacultures otherwise complete aquaculture, the start fish materials are natural fishes or eggs caught from nature. In complete aquaculture, in contrast, the start fish materials is eggs obtained by artificial aquaculture conditions, and it enable to produce fishes which does not rely on natural eggs or frys.

In other words, complete aquaculture creates a sustainable cycle. Because complete aquaculture does not catch natural juveniles or adults, it does not deplete natural stocks and allows for stable fish production.

The complete cultivation of bluefin tuna was first successed by Oshima Station, Aquaculture Research Institute, Kindai University in 2002.

Complete aquaculture of tuna is attracting high expectations as a technology that will enable to supply tunas without affecting natural tuna resources.

We visited Oshima Station, Aquaculture Research Institute, Kindai University as part of the project "Sustainable tuna".
(See For sustainability → Site visit to Kindai Univ.)

Scheme of complete aquaculture

Aquaculture is a method that allows for a stable supply of fish while also protecting natural resources. Espcially, the complete aquaculture allows fish to be produced without affecting natural resources, and aquaculture, in which fish are grown from fry to adults, may also help protect natural resources, given that a higher percentage of fry can be raised to adulthood than in nature. Since the impact of aquaculture on natural resources varies depending on the type of seedlings used in aquaculture, consumers should be interested in the type of aquaculture when purchasing farmed fishes.