UN member states embraced "positive energy" as they began two weeks of talks aimed at finally negotiating a pact to protect and preserve vast portions of the world's seas.

Following more than 15 years of formal and informal talks, negotiators have gathered in New York for the third time in less than a year in what is expected to be a final and decisive session.

Yet, as the discussions, which are scheduled to last until March 3, began on Monday, cautious optimism appeared to be taking hold.

"I hope we've come together here with a will to get us to the finish line," conference chair Rena Lee said, as quoted by AFP, as the talks began, adding that "an agreement that is universal, that is effective, that is implementable and that is future-proof is within our reach."

At the conclusion of the opening day, she stressed, "There is a lot of positive energy in this room. So it behooves us to enhance this positive energy, keep our focus, keep our eyes on the prize, and really work to make this (conference) final."

Lee also welcomed actor and activist Jane Fonda, who handed her a petition on behalf of ocean defenders worldwide, with 5.5 million signatures calling for a "strong" treaty.

A historic agreement signed in Montreal in December at the United Nations COP15 biodiversity summit is adding to the air of optimism.

Countries then committed themselves to safeguarding 30% of the world's lands and seas by 2030 -- a nearly impossible challenge if it fails to include the high seas, of which only about one percent is now preserved.

The high seas begin at the edge of a country's Exclusive Economic Zone, which can extend up to 200 nautical miles (370 kilometers) from its shore. As a result, they are subject to the jurisdiction of no country.

Despite accounting for more than 60% of the world's oceans and over half of the planet's surface, the high seas have historically received significantly less attention than coastal waters and a few iconic species.

But with no borders at sea, there is "just one ocean, and a healthy ocean means a healthy planet," Nathalie Rey of the High Seas Alliance, which includes some 40 NGOs, said as quoted by AFP.

'Failure is still possible'

Ocean ecosystems, which are under threat from climate change, pollution, and overfishing, produce half of the oxygen we breathe and help to minimize global warming by absorbing a large portion of the carbon dioxide released by human activities.

Notwithstanding some observers' hope and the informal conversations since the last session in August, ocean defenders warn that failure remains a possibility.

"If they do fail again, I think it really calls into question the process itself," Liz Karan of Pew Charitable Trusts said, as quoted by AFP.

Laura Meller of Greenpeace Nordic warned that "we're already in extra time."

"These talks are one final chance to deliver. Governments must not fail."

The draft treaty, which is riddled with parenthetic sections and many choices, illustrates the extensive list of difficult subjects that remain on the table.

While the creation of maritime protected areas is a major component of the mandate, delegations are divided on how these sanctuary zones will be constituted.

There is also no agreement on how to analyze the environmental impact of activities such as high-seas mining.

Furthermore,  debate persists over how to split up eventual profits from the collection -- by pharmaceutical, chemical, or cosmetic manufacturers, for example -- of newly discovered marine substances. 

Developing countries, unable to fund costly research, express concern about being left behind while others profit.

Observers accused affluent countries, particularly European Union members, of making only a last-minute move in this direction during the August session.

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