Sea urchin, salmon die en masse off Hokkaido, hurting Japan's fishing industry

The mass devastation of marine life began in mid-September and has already caused 7.6 billion yen (S$90 million) in damages. As at last week, about 2,300 tonnes of sea urchin has died.
The mass devastation of marine life began in mid-September and has already caused 7.6 billion yen (S$90 million) in damages. As at last week, about 2,300 tonnes of sea urchin has died.PHOTO: UNSPLASH

TOKYO - Sea urchin and salmon are dying en masse off the Pacific coast of Hokkaido because of the "red tide", driving up retail prices nationwide and jeopardising the peak autumn fishing season.

The red tide, a proliferation of toxic algae blooms or phytoplankton, is a seasonal phenomenon in western Japan but this is the first year it has afflicted Hokkaido.

The mass devastation of marine life began in mid-September and has already caused 7.6 billion yen (S$90 million) in damages, an estimate by the Hokkaido prefecture government showed last Thursday (Oct 21).

This figure was a marked 65 per cent jump from the 4.6 billion yen in the previous update on Oct 8 - and the number is set to rise even further.

As at last week, about 2,300 tonnes of sea urchin has died, a loss of 6.84 billion yen. Another 21,300 salmon perished, amounting to a loss of about 55 million yen. The remaining 700 million yen in damages is due to deaths of other fish species and marine life, including yellowtail, rockfish and octopus.

This has grave implications for the fishing industry in Japan, while wholesalers, retailers and restaurants both in Japan and across the region will have to bear the brunt of rising prices amid the shortage of Hokkaido uni (sea urchin) and ikura (salmon roe).

Retail prices for Hokkaido produce have doubled - and even tripled at some retailers - in Japan amid a supply crunch that has caused several sushi restaurants, including conveyor belt sushi restaurant chain Sushiro, to raise prices.

Hokkaido Governor Naomichi Suzuki, noting that the crisis was of an "unprecedented scale", warned that the fallout of the red tide may last for at least four to five years as he appealed to Agriculture, Forestry and Fisheries Minister Genjiro Kaneko this month for urgent aid to protect fishermen's livelihoods.

No similar red tide has ever formed off the coast of Hokkaido. Its impact will last well beyond this autumn, as juvenile sea urchins are raised in a facility by artificial insemination before being released into the seas to mature over four to five years. Many of these would have died in the red tide.

Adding to the woes of Japan's fishing industry is the ongoing accumulation of pumice stones off the shores of Okinawa that began last week.

The stones, which are believed to have flowed west from an underwater volcano eruption in August off the Ogasawara Islands in the Pacific Ocean some 1,400km away, have turned Okinawa's pristine blue oceans and sandy white beaches into dull fields of cement grey.

Municipalities have tried to clear up the debris, only for the pumice to accumulate again overnight. This has grounded fishing boats as the stones are small enough to clog up boat engines. Fishermen also fear that fish in farming cages may mistake the stones for food and swallow them.


Wholesalers, retailers and restaurants both in Japan and across the region will have to bear the brunt of rising prices amid the shortage of Hokkaido uni (sea urchin) and ikura (salmon roe, above). PHOTO: UNSPLASH

Okinawa is now at the peak of the fishing season for diamondfish, also known as mahi mahi, while the peak season for diamondback squid is due to begin in weeks.

Fisherman Shinki Taira, 28, told the Okinawa Times newspaper in frustration: "There is nothing that can be done about this. It's terrible. How can pumice stones that have spread so far and wide be removed?"

Over in Hokkaido, where the fishing industry has also been stalled by the red tide, fishermen are up in arms.

Mr Hidetoshi Yokota, 61, a veteran fisherman of 40 years who captains a sea urchin boat, told Hokkaido broadcaster UHB in a report last Friday: "Only six tonnes of sea urchins has been collected so far. This is an amount that can be reached in two days in an average year."

Fishermen in his town of Akkeshi have decided to call it quits for this fishing season, given bleak prospects that the situation will improve while they grapple with rising fuel costs amid the global energy crisis.

Yet the provenance of the red tide - the phenomenon gets its name from how it turns seawater reddish brown - has puzzled researchers.


The fishing industry in Hokkaido has been stalled by the red tide. PHOTO: PIXABAY

Red tides are relatively common in western Japan off the main island of Honshu in spring and summer, but are said to have never occurred around Hokkaido.

One early reported theory had to do with potentially warmer water temperatures off Hokkaido due to climate change, with an intense heat wave this summer causing mercury levels to rise. This would make conditions conducive for the growth of certain types of phytoplankton that cause the red tide.

But Hokkaido University researchers have found that the current red tide was caused by a breed of plankton that thrives instead in cold waters, forming off the coast of Russia and flowing south via the Kuril Current.

"We hope to discover the mechanism of the red tide that formed in cold waters so we can predict when the next red tide will occur," Dr Takahiro Iida of Hokkaido University said.