She said destructive fishing practices -- namely explosives and the use of cyanide over the past 10 years -- were as much to blame for the decline as overfishing because they destroy crucial reef habitats, affecting reproduction.
"There are no predators to check the fish that eat the plants and the shellfish," Cabanban said.
"There is a cascading effect on the reef. With so many herbivores, the plant population declines and fish run out of food and they die," she said.
Scales, the study's co-author, said it was impossible to quantify how many fish were taken by explosives or cyanide because fishermen refuse to discuss it.
Conservationists fear that the growing demand for live fish -- an industry worth more than US$1 billion a year -- is adding pressure to coral reefs already threatened by warming oceans, development and pollution.
Some 88 percent of Southeast Asia's coral reefs face destruction from overfishing and pollution, the US-based World Resources Institute estimates. Most under threat were the Philippines and Indonesia, home to 77 percent of the region's nearly 100,000km2 of reefs.
Fishermen in Kudat -- a sleepy South China Sea port in Malaysia that depends almost entirely on fishing -- acknowledged that catches have declined. Their boats now travel to the neighboring Philippines to find prized reef fish.
The fishermen argue that there are plenty of fish and that they have few options.
"This is our livelihood," said Ismail Noor, 45, adding that he sometimes spends three days at sea in search of the fish.
"If we stop, we would have no income," he said.
Noor and his fellow fishermen insist they use only hooks and lines or nets. But the local fisheries department said the use of explosives remains widespread, despite campaigns that warn of the dangers of losing arms, legs and hands.
"Most villagers are stubborn and have always done bombing since they were children," said fisheries official A. Hamid Maulana.
"It is difficult to change attitudes," he said.
Conservationists say the answer is to establish international standards for managing the import and export of reef fish, and consumers must be educated about the need to avoid certain endangered fish.
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