Lofty ambitions, though, are likely to collide with hard-knuckled diplomatic bargaining. Some countries resist the creation of a new governing body to regulate the high seas, arguing that existing regional organizations and rules are sufficient. The commercial interests are powerful. Russian and Norwegian vessels go to the high seas for krill fishing; Japanese and Chinese vessels go there for tuna. India and China are exploring the seabed in international waters for valuable minerals. Many countries are loath to adopt new rules that would constrain them.

And so, the negotiations need to answer critical questions. How will marine protected areas be chosen? How much of the ocean will be set aside as sanctuaries? Will extraction of all marine resources be prohibited from those reserves — as so-called no-take areas — or will some human activity be allowed? Not least, how will the new reserve protections be enforced?

Russia, for instance, objected to using the phrase “long term” conservation efforts in the document that came out of the latest negotiations in July, instead preferring time-bound measures. The Maldives, speaking for island nations, argued that new treaty negotiations were urgent to protect biodiversity.

Several countries, especially those that have made deals with their marine neighbors about what is allowed in their shared international waters, want regional fishing management bodies to take the lead in determining marine protected areas on the high seas. Others say a patchwork of regional bodies, usually dominated by powerful countries, is insufficient, because they tend to agree only on the least restrictive standards. (The United States Mission to the United Nations declined to comment.)