After all, seafood -- per capita consumption in Japan is some 70 kilogrammes, among the highest in the world -- is a staple in Japanese homes.

Hence the shock when on Jun. 3, the Health, Welfare and Labour Ministry issued a statement advising pregnant women to limit their consumption of certain fish species because of fears of mercury poisoning.

These include the bright-red sea bream called 'kinmedai' (alfonsin) and swordfish, both of which are expensive delicacies. The seven fish species that are the subjects of the warning also include cheaper tuna and shark, and sperm whale.

''The public is very concerned,'' said Kazuhiko Tsurumi, who is coordinating the warning and response effort. He said the ministry has been deluged by phone calls from the public. ''We are trying to tell people that there is no reason to panic. The danger is only for pregnant women and even they do not have to fear if they limit their intake,'' he explained.

Already under pressure on the issue of whaling - this month's annual meeting of the International Whaling Commission blocked a bid by Japan to re-introduce commercial whaling, banned since 1986 - the fishing industry is alarmed too.

At the ministry, frantic enquiries came also from fishing companies worried about their sales. Following the official statement, the prices of the two expensive fish species on the list have plummeted in Tokyo's fish markets.

''Prices are down on average of 40 percent,'' said Norie Hara, who owns a small fish shop in Meguro, a residential area in Tokyo. ''The 'kinmedai' was much sought after, but not any more.'' At an average of U.S. dollar 10 per kg, selling 'kinmedai' meant good business for vendors.

Statistics from the Tokyo Metropolitan Government bear this out - it estimated that 'kinmedai' alone accounted for 3 million U.S. dollars of the total fish sales of 38 million dollars in the capital's metropolitan region for 2000. Not surprisingly, Tokyo is the biggest consumer market for fish and seafood products in the country.

But Japanese families are now worrying more about parts per million (ppm) instead of yen per kg. The ministry warning is that the mercury content in the fish, at 0.44 ppm, can harm foetuses. Mercury poisoning, in the form of methyl mercury, affects the nervous system and the symptoms and condition are similar to those found in Minamata - Japan's worst case of industrial pollution.

In an effort to reassure the public, the ministry has set up a website that contains surveys and charts to explain contamination levels in various fish species, including tuna and whale meat. Pregnant women, the ministry has advised, should not eat the fish more than two or three times a week.

But what worries environmentalists is the fact that the warnings were occasioned by the results of surveys conducted on local catches. Given that species like swordfish and tuna are on the top of the food chain and feed on smaller fish, which are known to have accumulations of poisonous methyl mercury, industrial pollution is once again under scrutiny.

Yukio Murata of the World Wildlife Fund Japan explained: ''Heavy metal, mercury and dioxin has been found in segments of sea beds in the seas surrounding Japan, a result of wanton discarding of chemicals by companies.''

Such industrial run-off is also seen as affecting Japan's most popular shellfish - short-necked clams. The densest populations are found in the Ariake Sea in southern Japan, but their harvests have declined precipitously - from around 160,000 tonnes in the eighties to 60,000 tonnes now.

Worse still, land reclamation in the Ariake Sea is adversely affecting clam habitat. Sand dunes are important sanctuaries for the rearing of short-necked clams, said Hideo Sakaguchi, a marine expert at the Mie University. Sakaguchi is now probing the drop in clam catches to examine the impact of dyke construction in the sea.

The reclamation is considered to have affected the entire Ariake Sea. With the issue becoming environmentally sensitive, the Agriculture, Forestry and Fisheries ministry is now conducting a study to examine the damage that reclamation is causing to the marine ecology there.

The official response cuts no ice with Sakaguchi. ''The government undertakes environmental surveys only after problems are suspected or recorded,'' he said. ''This is almost too late for the protection of marine life.''

What is suspected by environmentalists and researchers may well be confirmed by the fishermen of the Ariake Sea. In July last year, hundreds of fishermen protested against dyke construction following poor seaweed harvests.

Rampant overfishing in the waters off Japan, the danger of remaining fish stocks being contaminated by industrial poisons, and the destruction of coastal marine life are all contributing to the environmentalists' fear that Japan's self-sufficiency in food is declining further.

The country is already the world's biggest importer of marine products. To ensure the supply of the 10 million tonnes of seafood consumed annually, Japan imports around 5.2 million tonnes, a sum that accounts for about a quarter of the global fish trade.

Indeed, as a percentage of total fish production, Japan's share has plunged from 17 percent in 1973 -- the highest for any country -- to around 5 percent and is further expected to drop to 4 percent by 2020, according to a forecast from the International Food Policy Research Institute and the WorldFish Centre.

Rising prices and dwindling fish stocks, said the forecast, will also mean that by that time, Japanese will find themselves eating less fish, up to 10 kg per capita less.

Copyright © 2003. Inter Press Service. All rights reserved.

Mercury warnings panic fish-loving Japanese