Interior Secretary Ryan Zinke thinks that some of the places designated as national monuments in the past two decades are overprotected. Banning economic activity within these monuments, he says in a memo obtained by The Washington Post and Wall Street Journal, isn’t necessary to “protect specific objects.”

He’s wrong — especially when it comes to the ocean monuments currently in the secretary’s sights.

In 2009, President George W. Bush designated 86,000 square miles west of Hawaii as Pacific Remote Islands National Monument — to safeguard its coral reefs, hundreds of species of fish and many varieties of nesting and migratory birds. Parrotfish, sea turtles, albatrosses and 5,000-year-old gold coral are all mentioned in his proclamation.

When President Barack Obama expanded the protected zone in 2014, he drew attention to the area’s volcanic undersea mountains and the many rare or as-yet-undiscovered species living on them.

Zinke’s preliminary recommendation is to let commercial fishing resume in the Pacific Remote Islands and in the nearby Rose Atoll Marine National Monument. Yet commercial tuna fishing is precisely what put these ecosystems under pressure. To thrive, the creatures need to be undisturbed, and this protection has to extend far enough to allow them to roam.

The restrictions rankle fishing companies — but haven’t prevented them easily catching their annual quota of bigeye tuna near Hawaii. In fact, putting areas off limits helps keep the business viable, because tuna reproduce far more successfully when they’re allowed to mature. (So-called BFFs — big, fat females — lay 200 times as many eggs as smaller ones do, according to professor Robert Richmond, director of the University of Hawaii’s Kewalo Marine Laboratory.)

The same benefits accrue off America’s East Coast, where Obama created the Northeast Canyons and Seamounts National Marine Monument. This amounts to only about 1.5 percent of U.S. waters along the Atlantic Ocean, but it’s enough to help many overfished species recover. Protection has been in force there for only one year, but already more squid are being seen.

This progress will be for naught if President Donald Trump restores commercial fishing in the protected areas. To help sea life survive and recover, the U.S. — and the rest of the world, as well — should be moving to extend them further. Last year, 129 governments agreed to a goal of protecting 30 percent of the ocean by 2030, up from just 3.5 percent now. As climate change makes the seas warmer and more acidic, the need to preserve marine life will only grow. The Trump administration is wrong to be contemplating this backward step.

Bloomberg View