Two leading environmental organizations have issued a grim report Friday on human exploitation of the world's oceans that lie beyond national jurisdictions. From Paris, Lisa Bryant reports the study coincides with a United Nations meeting on ways to protect these waters.

Jointly published by the United Nations Environment Program and the Geneva -based World Conservation Union, the report warns of irreparable consequences to the world's oceans if human exploitation is not curbed.

The study focuses on the high seas - ocean areas that lie beyond national boundaries where huge fleets are trawling bottom beds for fish - and harming scores of other species in the process. Populations of tuna, cod and swordfish have plummeted by up to 90 percent over the last century. Another activity - illegal longline fishing - kills hundreds of thousands of seabirds each year. Pollution and climate change are also harming our marine environment.

The study's author, Kristina Gjerde, says there's still time to save these ocean ecosystems.

"But with increasing fishing going on everywhere, the ability to target remote sea mounts - these things are happening faster than the actual regulatory mechanism that is in place," she said. "So if we don't act now, we will essentially be forced to focus on restoring the ecosystem which is more expensive and less cost effective - and probably not beneficial to the planet.

Just how badly the world's oceans have been exploited is not entirely certain. Oceans are rich with plant and animal life - yet man has explored less than 10 percent of them.

" We know so little still, and the things we do could have irreparable impacts caused by relative ignorance," Gjerde said. "We have no idea about the interaction of these complex ecosystems."

The report comes as ocean experts are meeting at the United Nations in New York to look at ways to implement the law of the sea. Environmentalists like Gjerde want countries to adopt mechanisms for the high seas they already have in place for coastal regions - like establishing marine protected areas, and better understanding the impacts of human activities. But they also say the very fact countries are now talking about these problems is a major step forward.