'Open the dikes!' they cry as crisis hits Seaweed Day

Not many countries celebrate National Seaweed Day, but then, there aren't many that honour and esteem the marine vegetable in so heartfelt a way as Japan.

Not many countries celebrate National Seaweed Day, but then, there aren't many that honour and esteem the marine vegetable in so heartfelt a way as Japan.

Seaweed Day was on Tuesday, marking the date, in the year 710, that edible seaweed first appeared on a list of treasured produce offered in tribute to the Emperor. Thirteen centuries later, few Japanese go a day without eating it in some form - floating in miso soup at breakfast, chopped into strands as a garnish for lunchtime noodles, and, above all, as the dried and crinkly wrapping for sushi rolls.

On Seaweed Day, retailers give away free samples and the papers print photographs of grinning children chomping sheets of nori, as the dried and edible product is called in Japanese. But this year, angry demonstrations have taken place, questions are to be asked in parliament and government officials are reacting with defiance and confusion. For the nori industry is in crisis, and never has Seaweed Day been marked in such an atmosphere of trepidation and crisis.

The problem is in the Ariake Sea, a shallow bay created by the elaborate, convoluted coastline of Kyushu, where two-fifths of all Japanese nori is produced. Ariake nori is the best in the world, with the finest taste and the richest colour, a deep matt black-green. But this winter, the seaweed harvesters of Ariake Bay made an alarming find.

The nori they raised from the bottom was beige, instead of green, virtually tasteless and extremely sparse. Nationally, this year's seaweed harvest has dropped by 25 per cent or 1.2 billion sheets (it is bought and sold in paper-thin dried rectangles of 21cm by 19cm).

The crisis in the Ariake Sea accounts for 90 per cent of the shortfall. And there isn't much mystery about the cause of the seaweed failure - something like this has been predicted by environmentalists for years.

In the west of the Ariake Sea is Isahaya Bay, the site of one of the most controversial of Japan's many public works projects. Four years ago, 300 steel gates were lowered across the mouth of the bay as part of a project to reclaim it for farmland. The seaweed cultivators are sure responsibility for their own ruin lies with the reclamation and the bureaucrats from the Ministry of Agriculture.

A flotilla of 6,000 seaweed farmers in 1,000 boats rallied in protest last month. "Open the dikes!" they shouted and, less catchily, "Conduct an environment assessment survey!" Nobody knows exactly what is ravaging the nori, but theories include malnutrition due to a sudden and stifling excess of plankton, a phenomenon known as "red tide".

The ministry insists there is no scientific evidence of a link between the nori devastation and its land reclamation project. This is true - they have not allowed any scientific research.

The prices in the seaweed auctions, meanwhile, are creeping up, from 6 yen (3.6p) to nearly 10 yen a sheet in parts of Japan. It won't be long until they are passed on to the consumers. As for the long term, nobody knows, but the time may yet come when National Seaweed Day is marked by sad and distant memories.