A report released this week on the status of coral reefs around the world warned that Taiwan's coral reefs, especially those in its south and southeast waters, were under severe stress or had been heavily damaged, and that a trend of declining coral cover deserves attention.
The report, Status of Coral Reefs of the World: 2008, found that coral cover at 24 of the 49 sites surveyed in the country was lower than 30 percent.
The lowest coral cover sites were even less than 10 percent, the report said.
“Overall, monitoring is showing a general trend of declining coral cover on Taiwanese coral reefs,” said the report, released by the Global Coral Reef Monitoring Network on Wednesday.
While damage to coral reefs elsewhere in the world was caused largely in 1998 by bleaching related to the strong El Nino effect that caused a rise in sea temperatures, the main culprits behind coral reef deterioration in Taiwan were inappropriate fishing methods and excessive development, experts said.
“For coral reefs in Taiwan, the most serious impact would be excessive fishing and silt sediment,” said Dai Chang-feng (戴昌鳳), a professor at the Institute of Oceanography at National Taiwan University.
He said that some fishing methods, such as using explosives, cause considerable damage to coral reefs.
The report said that the nation's coastal areas had also been under extensive infrastructure development, including aquaculture, agriculture and resort building, along with the growth in population. As a result, serious soil erosion has led to frequent landslides in rainy and typhoon seasons and massive sediment flows into reef areas.
Rising sea surface temperatures represent only part of the problem for coral reefs in Taiwan, Dai said.
The report also said that macro-algal cover has increased in about half of the surveyed sites in the country, accompanied by higher sedimentation loads and increased water turbidity, suggesting continuous reef degradation and a possible phase shift from coral-dominated to algal-dominated reef communities.
Dai said that the increase of macro-algal cover is a consequence of sewage from coastal towns and villages discharged over reefs without proper treatment, resulting in algal proliferation and coral loss.
The macro-algal cover problem is more serious in the north than in the south, Dai said.
To improve the coral reefs' situation, the report suggested increased socioeconomic and ecological monitoring to provide reliable data and information for better coastal management.