(CBS NEWSPATH) – Conservationists are calling it a victory for the high seas and marine life. United Nations diplomats from nearly 200 nations have agreed on a high seas treaty that protects large parts of the Earth’s oceans.

“I mean, this is huge. This is really, I think, a keystone agreement if we’re going to try and protect thirty percent of the ocean,” says Nichola Clark, Officer for Protecting Ocean life on the High Seas at The Pew Charitable Trusts.

More than a decade of debate over funding and fishing rights had stalled the landmark treaty at the UN – as the high seas remained vulnerable to chemical and plastic pollution, overfishing and other threats. “There is a lot of destruction going on in the world’s oceans. 90 percent of the big fish are gone. We know what’s happened to the whales. This is why we need to start urgently putting something back in the way of areas that humans cannot exploit,” says Charles Clover, Executive Director of Blue Marine Foundation.”

The high seas are areas beyond any country’s control, making up almost half of the Earth’s surface. Marine biologist Olive Heffernan says, “Right now only one percent of the high seas is protected within a marine reserve, and we need to get to 30 percent by 2030.”

Once countries formally adopt the agreement, work can begin to protect the deep blue sea.

The treaty is seen as a crucial part of a global effort to bring 30 percent of the world’s land and sea under protection by 2030.