Sushi from Sri Lanka

Many tourists arrive in Japan, anxious to enjoy the traditional cuisine of sushi in the country of its origin. Decent sushi is never available abroad. Red maguro (tuna), succulent sea urchin, delicate squid slices and plump shrimp sit elegantly on vinegar rice. This is the taste of real Japan, you may think. But more often than not, chances are the seafood came from distant seas, particularly if you are eating sushi at the popular kaiten (rotating) sushi bars.

Tuna often hails from New Zealand or Sri Lanka, while sea urchin is sourced from Canada or Chile. Shrimp is from Vietnam, salmon from Norway and sea bream from Panama. After all, 50 per cent of marine products consumed in Japan is imported.

Japan is the top marine food importer in the world, purchasing 3.3 million tonnes last year. The imports are cheaper and more accessible to informal, casual kaiten boasting lower prices than classy sushi bars. (Local fastidious epicures would choose 'near-sea' fish in season, although the bill can be double or triple.) It is yet only a small slice of a significant issue for Japan, where the 'food self-sufficiency ratio' continues to drop - a measure showing how much of the food eaten in the country is domestically produced. The ratio was 79 per cent in 1960 when the government began taking such statistics.

But it is now 40 per cent, unchanged for the sixth straight year. As affluency grew, the diet moved from the traditional to a wider menu, of grains, meat and fish from abroad as well as oil, ingredients and other processed food. As a result, Japan is at the bottom in independence in food supply, among industrialised nations - 29th among 30 Organisation for Economic Co-operation and Development member nations in 2001. Except for rice, Japan relies on imports for 72 per cent of grain consumption, including feed. Particularly worrying is that Japan produces only 14 per cent of wheat consumed, 6 per cent of beans eaten on its own - the two other main diet staples. If the food inflow is disrupted, many are concerned Japan will be short of beans to make tofu and miso or wheat for bread or noodles.

Alarmed by the falling ratios, the government in 2000 set a target to raise the supply to 45 per cent by 2010. But there are few signs of success. Rising imports are driving local farmers into tougher competition and the government to more protective policies, the reverse trend to free trade initiatives. Agriculture ministry officials are quickly reviewing the target rate for drawing up a new plan before March. But how can you control the appetite of consumers in the age of gluttony? There seems to be no way of stopping a trend that is already visible also in China.