The Galápagos, Charles Darwin once said, are “a little world within itself.” Many of the finches, tortoises and other animals that he saw there in 1835 — and that inspired his ideas on evolution — know no other home on Earth.

But the sharks, whales, sea turtles and manta rays that teem in the waters around the wildlife-rich islands are on the move. Like Darwin, who spent only five weeks in the Galápagos, many sea species there are transient, regularly migrating outside that little world and to neighboring island chains.

On Friday, the government of Ecuador announced it will curb fishing in more than 20,000 square miles of ocean to the northeast of the archipelago, in essence erecting guardrails around an underwater animal freeway between the Ecuador’s Galápagos Islands and Costa Rica’s Cocos Island.

“It’s like creating a new highway for them to travel,” said Gustavo Manrique, Ecuador’s minister of environment, water and ecological transition.

No fishing will be allowed in half of the newly protected area, while longline fishing will be banned in the other half.

Since 1998, more than 50,000 square miles surrounding the Galápagos has been set aside as a marine reserve, protected from industrial fishing. But schools of bulbous whale sharks and trim scalloped hammerheads zip between archipelagoes in search of food or mates, putting themselves at risk of being hauled up by fishers eager to sell their fins in Asia, where many regard shark fin soup as a delicacy.

“The boundaries are created by humans,” Manrique said in an interview Friday. “But the species, they don’t know about boundaries.”

The decree Friday from Ecuadoran President Guillermo Lasso comes as calls to safeguard more of the world’s oceans grow louder. The burdens on ocean life — from littered plastic, increased temperatures and more-acidic waters in addition to overfishing — are conspiring to make the oceans inhospitable for many forms of marine life upon which millions of people depend.

Ocean conservation advocates hope the announcement from Ecuador is a harbinger of more protections to come.

“Why is this one important? I guess, reflecting on it a little bit, it’s because it’s the Galápagos,” said Matt Rand, who leads large-scale marine habitat conservation at the Pew Charitable Trusts. “The fact that they’re expanding the protections for Galápagos, this global icon for conservation, is a symbol globally.”

Ecuador is cooperating with Colombia, Costa Rica and Panama to link their marine reserves and protect a span of the Pacific coast. In recent years, Chile, New Zealand, the United States and other nations have expanded their own protections for marine life.

Those efforts are underway as the world’s nations set out to conserve a tenth of the world’s coastal and marine areas as part of a global agreement called the Convention on Biological Diversity. Many scientists and politicians are urging nations to up that percentage.

Among wildlife havens, the Galápagos, as always, stand apart. The fertile waters around the islands some 600 miles off the South American coast teem with more sharks than anywhere else in the world and make Ecuador one of the world’s top tuna producers.

Yet legal protections there alone only go so far.

By one estimate, about a half-million sharks were killed annually in the waters off Ecuador between 1979 to 2004, their bodies often dumped overboard after the fins were harvested. The taking of sharks around the once unspoiled island chain threatens not only the apex predator but each fish down the food chain.

Enric Sala, a National Geographic explorer-in-residence who studies the sharks, said it is all too common to still see fishing vessels trolling ostensibly protected waters and casting illegal longlines, with hundreds of baited hooks that can ensnare sea turtles, sea lions and even diving sea birds. As recently as last year, satellites spotted a large Chinese fishing fleet near the archipelago.

Manrique, the government’s environmental minister, conceded there is illegal fishing in existing protected areas.

“Today, the government of Ecuador is creating a new protected area outside of the marine reserve, right?” Sala said. “But my question to them would be: Are you going to do something to increase the protection of the core of the marine reserve?”

In the coming days, Manrique said, the government will announce steps to better fund conservation efforts — a tall order for a developing country facing an outsize impact from climate change.

It’s ironic, he said: Less than 1 percent of the world’s carbon dioxide emissions come from Ecuador. “It’s really interesting, that contrast.”