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Friday, May 30, 2008
Japan finding itself in hot water
Impact of rising temperatures being felt in fisheries, agriculture and other industries
SADO, Niigata Pref. — Kyuichi Sakano, head of Niigata's fixed shore net fishing association, sighed in dismay one day last December as his fishing boats came back yet again without any yellowtail.
"The business is very severe," said Sakano, who owns two stationary fishing nets off Sado Island.
In addition to the salaries of about 80 employees who work for him, Sakano needs to satisfy some 800 local investors. But because of poor catches, his association was unable to pay dividends in the business year that ended last July.
Sado, which lies off northern Niigata Prefecture in the Sea of Japan, is popular for "kanburi" yellowtail, a tasty variety caught in November and December, when the fish swim south to avoid colder currents.
But in the past two years, Sado has been suffering from low catches of yellowtail partly due to rising water temperatures in the area.
In the 2006 business year, Sado's fishermen brought in 95 tons of yellowtail between November and February and 107 tons during the same period in business 2007 — way below the 467 tons caught in business 2003.
Despite growing awareness of global warming — which figures to be the main topic at the Group of Eight summit this July at Toyako, Hokkaido — its impact on daily life may still be elusive for many people.
But climate change appears to have begun affecting some sectors, especially in agriculture and fishing, and has been keenly felt by the people engaged in those industries.
According to the Meteorological Agency, the annual average water temperature in the Sea of Japan has risen 1.6 degrees over the past 100 years — three times the global average increase of 0.5 degree.
Researchers agree it is almost impossible to prove climate change is the sole cause of the sudden decline in the yellowtail catch off Sado. They say a number of factors can change migratory patterns, including lack of food and temporary changes in sea currents.
But most agree that the higher seawater temperature has altered which species of fish are caught in the area.
In the past decade or so, increasing numbers of Spanish mackerel, which usually wander in the warmer East China Sea or the Seto Inland Sea, have been caught off Sado Island and other parts of the Sea of Japan.
"Seawater temperature changes in a cycle of 10 to 50 years in the Sea of Japan, which is a natural phenomenon," said Hideaki Kidokoro, a researcher at the Japan Sea National Fisheries Research Institute in Niigata. "Catches of sardine increase during a low-temperature cycle, while yellowtail increase in a high-temperature cycle."
But it is a worrisome possibility this cycle is being disrupted by global warming, which is largely deemed a man-made phenomenon, he said.
"We don't know whether this change of cycle will continue if the seawater temperature rises because of global warming," Kidokoro said. "The ecological system responds to surrounding conditions and we're not sure what will happen."
In warmer parts of Japan, higher seawater temperatures have damaged one of the nation's most popular diving spots.
Last summer, about 80 percent of the coral reefs in 30 monitored locations in Sekisei Lagoon off Okinawa's Ishigaki Island suffered from bleaching because of higher water temperatures.
"It was as if snow fell in the sea," said Hajime Hirosawa, an official at the Environment Ministry's International Coral Reef Research and Monitoring Center on Ishigaki.
In recent years, coral reefs around the world have been threatened by bleaching believed to have been caused by rising sea temperatures due to global warming and by a sharp increase in crown-of-thorns starfish, which eat coral.
The ideal sea temperature for a coral reef is 18 to 30 degrees, but the average temperature around Ishigaki rose to 32 last July and August.
One of the reasons, Hirosawa said, was that no typhoons hit the region until late summer.
Normally, the area is lashed by typhoons almost throughout the summer, reducing the sea's temperature by constantly causing surface and deeper waters, and ocean waters and shoreline waters, to mix.
"Global warming is not the only reason" causing coral bleaching, Hirosawa said. "But a higher seawater temperature adds stress to coral reefs."
Higher temperatures affect much more than marine life. In Kyushu, climate change could be causing the quality of rice to deteriorate.
Between 2003 and 2007, an average of 20.9 percent of the rice harvested in 200 select locations in Fukuoka Prefecture was classified as "first class," down sharply from an average of 64 percent between 1996 and 2002, according to data compiled by the agriculture ministry.
Typhoon damage was the primary cause, acknowledged Satoshi Morita, a senior researcher at the Chikugo branch of the National Agricultural Research Center for Kyushu Okinawa Region, but he argued that global warming has contributed to the decline in rice quality.
"What drew my attention is that the temperature was high even though there were more cloudy days than usual," Morita said. "This may be because of global warming."
According to data from the Meteorological Agency, Fukuoka's average temperature in August and September, when the rice ears up (when the grains start to appear) was 26.9 degrees between 2003 and 2007. That's 0.5 degree higher than what the average was for the same months between 1996 and 2002.
If the temperature is above 26.5 degrees when the rice plants ear up at the end of August through mid-September, the grains turn milky white, or less translucent than normal.
"Such rice, when cooked, will be mushy," which consumers do not like, Morita said. "Because these rice grains are softer, they easily crack during transport."
To fight this trend, rice farmers are instructed to delay planting by a week or two in June so that the rice will ear up after the weather cools in the fall.
The research center has also developed a new strain called Nikomaru, which is more resistant to high temperature. The Nagasaki and Oita prefectural governments are encouraging their farmers to plant Nikomaru.