More than 20 new marine protected areas in coastal waters were announced at the third U.N. ocean conference this week. Experts say thousands more are needed.

Remote coral atolls in the Caribbean. Habitat for threatened sharks and rays around a Tanzanian island in the Indian Ocean. And 900,000 square kilometers of the Pacific Ocean around French Polynesia.

These are some of the millions of acres of water now set aside as part of an international goal to protect 30 percent of the ocean by 2030. More than 20 new marine protected areas were announced at the third United Nations Ocean Conference, which ended on Friday in France.

Countries and territories pledging new areas included Chile; Colombia; French Polynesia; Portugal; Samoa; Sao Tome and Principe; the Solomon Islands; Tanzania; and Vanuatu.

“Protecting the ocean is beginning to become fashionable,” said Sylvia Earle, a marine biologist and oceanographer who served as chief scientist of the National