The report noted overfishing and climate change as two of the most serious threats to the world’s oceans. It said higher acidity levels caused by carbon dioxide emissions are also a problem. Other threats include the use of explosives for fishing, as well as the run-off of toxic materials and other pollution.

LAURETTA BURKE: "Overfishing is the most widespread threat affecting about 55 percent of the world’s reefs. The threat is particularly high in Southeast Asia. Watershed based pollution and coastal development affect roughly a quarter of the world’s reefs."

Burke says while the reefs around Australia are the best preserved, those in Southeast Asia are the most threatened. Ninety percent of them are at risk, largely because of overfishing.

The report says coral reefs are critically important. It says better management practices and policies must be established to reduce the threats to these valuable ecosystems. I’m Christopher Cruise.

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MARIO RITTER: Next, we turn to environmental activist Marcus Eriksen. He goes sailing in search of objects floating near the ocean’s surface. But, as Shirley Griffith explains, he is not hoping to catch fish.

SHIRLEY GRIFFITH: Marcus Eriksen is not really fishing. He is catching plastic in the Atlantic Ocean. Eriksen wants to publicize the growing buildup of plastic waste in our oceans and to study its effects.