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Japanese zoologist’s coral findings inspire Taiwanese films

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Kyodo

It was 1939, and Siro Kawaguti, a Japanese zoology lecturer at Taihoku Imperial University (now National Taiwan University), was curious about the thick, pinkish slicks he saw floating on the surface of the sea off the coast of Taiwan. So he took samples back to his lab for examination.

One year later, and 40 years before similar discoveries would be made in the West, Kawaguti began to publish his findings, which, being in Japanese, were largely ignored until recently, with the effects of climate change leading to new interest in his work.

The thick, pinkish slicks he found that day turned out to be coral larvae, 52 species of which he eventually identified off the northern coast, and 71 more in the south.

Each year after the full moon in May or June, northern coral spawn for about a week. During this time, which corresponds with the lunar birthday of the sea goddess Matsu, massive numbers of tiny cells spew out of living coral. These are the coral eggs and sperm, which mix in the ocean as it becomes warmer and calmer because of the lunar cycle.

In recent months, the Association of Fishing Culture and Conservation in Yilan County, on Taiwan’s northeast coast, has been filming the spectacular mass spawning of corals discovered by Kawaguti.

“We owe him a great deal,” Liao Da-wei, secretary-general of the association, told Kyodo News. “I would have felt ashamed if we didn’t pick up where he had left off.”

After years of seeking sponsorship, the association finally obtained funding to rent gear and equipment. It finished the recording and posted the film on YouTube in June.

Its goal is to broadcast the annual coral spawning on television and the Internet so more people know the beauty and importance of coral reefs, he said.

An avid diver, Liao described the mass coral spawning at night as being like “swimming in a big cup of bubble tea.”

However, Liao’s purpose in filming coral spawning off the Yilan coast is not just to celebrate Kawaguti’s pioneering achievement in coral science.

His association is also interested in conservation. And coral is in trouble.

There are more than 6,500 coral species in the world and 350 have been identified in Taiwan. Most are hard corals found in shallow waters, according to Jeng Ming-shiou, a research fellow at the Biodiversity Research Center of Taiwan’s Academia Sinica.

But while coral reefs comprise only about 0.5 percent of the ocean floor, they are important for social and economic reasons.

The U.S. Department of Commerce (DOC) estimates that over 500 million people around the world depend on coral reefs as a habitat for food source marine life.

They also provide jobs in fishing, tourism and recreation, while protecting coastlines from damage during storms. Coral reefs are estimated to add approximately $30 billion to the world economy annually.

But it is not as though life is easy for coral.

Among Kawaguti’s discoveries was that clionidae sponges have a negative impact on coral colonies as they spread by eroding living corals, and that zooxanthellae, an algae that lives in coral tissues, has a mutualistic relationship with reef-building corals.

When coral is under stress, it expels the algae, which causes it to lose its color, a condition known as coral bleaching. However, as the coral and algae are interdependent and need each other to survive and exist, this can threaten the life of both.

Kawaguti also discovered that coral ecosystems are sensitive to changes in water temperature, such as during the El Nino phenomenon.

The 1997-1998 El Nino caused extensive coral bleaching and a subsequent die-off worldwide, including around Taiwan, with damage estimated at over $200 billion.

Apart from El Nino and global warming generally, coral reefs are threatened by overfishing, coastal development, sedimentation and pollution.

The combination of threats caused by human activity has placed the world’s coral reefs under considerable pressure. The U.S. DOC estimates that about 20 percent of the world’s coral reefs are damaged beyond recovery, and 50 percent of those remaining are at risk of collapse.

In Taiwan, some suggest radiation from three nuclear power plants also threatens the health of the island’s coral reefs, half of which are already damaged beyond recovery.

“Except for some outlying islands, the state of Taiwan’s coral reefs is miserable,” said Dai Chang-fong, professor of marine biology at NTU’s Institute of Oceanography.

In pristine condition only 30 years ago, he said, “people have not taken the matter seriously, thinking the reefs would repair themselves. What they didn’t know is that once they are gone, it is very hard to get them back.”

Kawaguti earned his Ph.D. at Taihoku Imperial University in 1943 and remained involved in coral research after he returned to Japan in 1949.

In all, he published more than 50 scientific papers on coral and coral reefs, helping to form the foundation of modern coral reef biology.

As most were written in Japanese, a working group was established by the Japanese Coral Reef Society (JCRS) to translate Kawaguti’s early work into English.

Kawaguti retired from Okayama University in 1973 and passed away in December 2004 at the age of 96, leaving an endowment to the JCRS and Zoological Society of Japan to support young scientists with outstanding achievements in coral reef research.