UNITED NATIONS (AP) — Members of the United Nations adopted the first-ever treaty to protect marine life in the high seas on Monday, with the U.N.'s chief hailing the historic agreement as giving the ocean “a fighting chance.”

Delegates from the 193 member nations burst into applause and then stood up in a sustained standing ovation when Singapore’s ambassador on ocean issues, Rena Lee, who presided over the negotiations, banged her gavel after hearing no objections to the treaty’s approval.

The treaty to protect biodiversity in waters outside national boundaries, known as the high seas, covering nearly half of earth’s surface, had been under discussion for more than 20 years as efforts to reach an agreement had repeatedly stalled. But in March delegates to an intergovernmental conference established by the U.N. General Assembly in December 2017 agreed on a treaty.

The new treaty is under the U.N. Convention on the Law of the Sea, which came into force in 1994, before marine biodiversity was a well-established concept. It will be opened for signatures on Sept. 20, during the annual meeting of world leaders at the General Assembly, and it will take effect once it is ratified by 60 countries.

The treaty will create a new body to manage conservation of ocean life and establish marine protected areas in the high seas. It also establishes ground rules for conducting environmental impact assessments for commercial activities in the oceans.

Secretary-General Antonio Guterres told delegates that the adoption of the treaty comes at a critical time, with the oceans under threat on many fronts.

Climate change is disrupting weather patterns and ocean currents, raising sea temperatures, “and altering marine ecosystems and the species living there,” he said, and marine biodiversity “is under attack from overfishing, over-exploitation and ocean acidification.”

“Over one-third of fish stocks are being harvested at unsustainable levels,” the U.N. chief said. “And we are polluting our coastal waters with chemicals, plastics and human waste.”

Guterres said the treaty is vital to address these threats and he urged all countries to spare no efforts to ensure that it is signed and ratified as soon as possible, stressing that “this is critical to addressing the threats facing the ocean.”