Tuna consumption in Japan appears to have reached its upper limit. With high domestic production, increasing imports were still needed to fulfil demand. However in recent years a declining trend is noted in production, import and consumption.

Tuna generally includes skipjack in international trade, but is deemed to be different for the Japanese. So, in this article, sometimes skipjack will be treated separately from other tunas.

Domestic production of tuna remained at a high level of more than 300 000 mt/year for over 20 years. In 1996, total tuna catch dropped to 280 000 tonnes, the lowest level during this period. The decline is due to a number of reasons such as a decrease in abundance of some tuna stocks, a reduction in the number of longline fishing vessels and a drop in the catch of yellowfin tuna by purse seiners. According to many scientists, the decline in catch by purse seiners is not attributed to reduced stock size but to a change in water condition.

Skipjack catch on the other hand has fluctuated between 300 000 and 400 000 mt while in some years it exceeded 400 000 mt. In 1996, the catch dropped to 273 000 mt, the lowest in more than 20 years, probably due to the current sea conditions.

Japanese purse seiners operate mainly in the western Pacific, while a couple of vessels operate in the Indian Ocean. Catch by purse seiners in the Indian Ocean decreased sharply in recent years, from 42 000 mt in 1993 to 11 000 mt in 1996. All tunas caught by Japanese purse seiners in the Indian Ocean are landed at a Thai port and exported.

Between 1985 and 1993, total tuna imports into Japan increased yearly as the yen strengthened, to reach a plateau at 320 000—330 000 mt. Of the tuna imports fresh tuna continued to expand until 1995 but decreased slightly in 1996. Tuna imports expanded to the 330 000 mt level in 1993 due to a sharp increase in yellowfin imports caught in large volumes in the western Indian Ocean by Taiwanese longliners. However the big catch level did not continue and yellowfin imports have declined since then. On the other hand, bigeye imports have increased to offset the decline. While skipjack imports were stable until 1989 at a level of 2 000 to 4 000 mt, they increased to 26 000 mt in 1990 and 54 000 mt in 1993. Since then, the imports have stabilised at a current level of 50 000 mt. As skipjack caught with pole and line began to be used for sashimi instead of raw material for katsuobushi (dried and cured fish product) or canned product, imports for the production of katsuobushi increased.

The biggest supplier of tuna to the Japanese market continues to be Taiwan. Imports from Taiwan in 1996 were 95 640 mt, which accounted for 30% of total tuna imports. Indonesia is ranked second, with 47 876 mt, just half the volume from Taiwan. Indonesia is followed by Korea, the Solomon Islands, Singapore and Honduras. About half of the total tuna imports from Indonesia consist of skipjack. Until 1994, tuna imports from the Solomon Islands were 4 000 mt or less and never reached the top-ten-suppliers rank, but since then, Solomon Islands’ exports to Japan have sharply increased.

Japanese tuna exports are much lower than the imports. The exports of skipjack have shown a downward trend (from 57 000 mt in 1993 to 19 000 mt in 1996). Major countries of destination are Thailand, Singapore and Indonesia. In 1996, the Thai market was by far the biggest importer with 17 000 mt. Skipjack exported to Thailand is used for canning. The second main species exported is yellowfin tuna. As in the case of skipjack, yellowfin also showed a downward trend declining steadily from 47 000 mt in 1992 to 32 000 mt in 1996. The main markets was Thailand, followed by Guam and Puerto Rico. Japan exported 13 000 mt of yellowfin tuna in 1996 to Thailand for its canning industry. The principal reason attributed for declining exports of tuna is the appreciation of the value of the yen.

Table 3: Imports of fresh and frozen tunas - Japan

Tuna products

In Japan, tuna is used for sashimi (raw fish), canned tuna and katsuobushi. Katsuobushi is made from fillets of skipjack which is boiled, dried, smoked and moulded. Limited quantities of tuna are also processed into other products, but they are much less important.

Bluefin, southern bluefin, bigeye and yellowfin tuna, caught using longlines, are used for sashimi. Of these, bluefin and southern bluefin are the most valuable fish, followed by bigeye tuna. The belly flesh, which contains a lot of fat, is highly appreciated. Marlin caught with longlines are also used for sashimi. Skipjack harvested with pole and line were used for a long time as raw material for katsuobushi and canned tuna as well as for sashimi, but recently skipjack are used mainly for sashimi. Albacore, which were used only as raw material for canned tuna, are increasingly used for sashimi today. Yellowfin caught by purse seines are mainly used for canned products both in domestic and foreign canneries. The majority of skipjack caught by purse seines are used for processing katsuobushi. A small portion is used as raw material for canned tuna both in domestic and foreign canneries. Limited quantities of yellowfin and skipjack are eaten raw.

With the appreciation of the yen in 1995, imports of tuna increased and the total supply of tuna in the Japanese market expanded. As a result, the price of tuna declined and consumption grew. However consumption almost levelled off after 1990, and decreased in 1996. This was partly due to reduced supply and partly due to a disease breakout caused by pathogenic E. coli. In addition, the tuna market had trouble with carbon monoxide. If tuna is packed in an air-tight container filled with carbon monoxide, its bright red colour does not fade even after a long time and it looks fresh. In fact the flesh deteriorates and occasionally this may cause food poisoning. To prevent this, the Ministry of Health and Welfare strengthened its inspection system. As a result of these developments, an unfavourable image of sashimi tuna was created among consumers and this also led to a decline in consumption.

Sashimi consumption has two main components: consumption in the food service industry, and consumption at home. According to statistics compiled by the Prime Minister’s Office, the annual per capita household consumption of sashimi tuna increased until 1995 and decreased subsequently, for reasons mentioned earlier. Total household consumption increased annually, from 118 000 mt in 1992 to 133 000 mt in 1995 and declined to 123 000 mt in 1996. The estimated consumption in the food service industry was 373 000 mt in 1992 and 409 000 mt in 1993, but later dropped to 346 000 mt in 1996.

Data on skipjack, based on a Statistical Year Book compiled by the Ministry of Agriculture, Forestry and Fisheries, and estimates by the Japan katsuobushi Association show that the demand for skipjack sashimi increased until 1991 but since then has fluctuated widely. The 1991 level could be considered as the upper limit of consumption. Skipjack caught with pole and line is most often used for sashimi and fetches the highest price. Limited quantities of skipjack caught by purse seines are also used for sashimi.

Katsuobushi is sliced and packed in small plastic bags to be sold in retail stores or used as raw material for broth or seasoning. The rate of consumption is level or increasing only slightly. While the consumption of sliced and packed product is stable, the raw material use is slightly increasing. Skipjack caught with pole and line is sometimes used as raw material for katsuobushi but is almost exclusively consumed raw today. Accordingly, imports of skipjack have increased. In recent years, around 50 000 mt of skipjack have been imported and almost entirely used for the production of katsuobushi. Skipjack used for katsuobushi should be of low fat content. It is said that skipjack imported from Indonesia is of the highest quality for katsuobushi. Recently, however, users have had problems with the quality of fish which varied widely.

Table 5: Supply and consumption of skipjack (in 1000 t)

Conclusion

The Domestic production of tuna, excluding skipjack, has been stable for a long period of time. On the other hand, imports of tuna have increased since 1985 due to the appreciation of the yen. Accordingly, the demand for sashimi tuna has expanded. However, in the past few years, imports have fluctuated and subsequently levelled off with demand. Considering this trend together with the stock condition of each tuna species, it is expected that the current balance between supply and demand will be maintained. Initially the demand for skipjack sashimi increased, but later began to fluctuate. As the skipjack use shifted from katsuobushi and canned tuna to sashimi, raw material for katsuobushi was in short supply and consequently skipjack imports expanded sharply. However, today, the demand for katsuobushi is approaching its upper limit and it is said that products of inferior quality are detected in imports from time to time. Therefore, further expansion of imports is not envisaged.

(Source: INFOFISH International, 1/98, 19—23)