What’s the best way to protect coral reefs and underwater sponge gardens from being damaged by fishing gear? Ban bottom trawling from a huge swath of ocean off of Southern California.

That’s according to the Pacific Fishery Management Council, which voted earlier this week to create a gigantic new marine conservation area larger than New Mexico off the California coast. It includes nearly all of the ocean off Southern California.

The plan now goes to U.S. Secretary of Commerce Wilbur Ross to decide whether to approve the Council’s unanimous recommendation.

The Pacific Fishery Management Council voted to protect a huge swath of ocean off the California coast from bottom-trawl fishing on April 9, 2018. The new protected area is in green. Areas previously protected are in orange. Courtesy Oceana

Bottom-trawl fishing boats are the number one threat to deep-sea corals and sponges, according to the National Oceanic and Atmospheric Administration. Those are corals and sponges that grow at least 160 feet below the water and don’t need sunlight to survive. Heavy fishing gear that drags along the ocean floor can break, crush or flatten the delicate structures.

Because they grow so deep, you’re unlikely to spot them while snorkeling. Geoff Shester, a senior scientist with the environment group Oceana took a submersible beneath the waters off Southern California to see them.

“It looked like a fantasy world that only Dr. Seuss could have made up," he said. "Huge sponges, corals that come up in large spirals -- they actually glow in the dark because of bioluminescent algae and life that live on them. It looked like a Las Vegas light show.”

An octopus hides out while a squat lobster stands guard beneath a vase sponge in the Oceana's West Santa Barbara Island study area. Courtesy Oceana

In Southern California, the deep-sea coral reefs and sponge gardens are largely untouched. The sea floor drops off so rapidly that it has kept bottom trawling fishing boats away because it’s too difficult for their gear to reach the bottom. The corals and sponges off the Central and Northern California coasts, meanwhile, are shallower. That enables boats dragging heavy fishing gear to net bottom-dwelling fish like lingcod, sole and rockfish. But they also to damage ecologically important areas.

Beyond being beautiful and valuable in and of themselves, deep sea corals and sponges are important habitat for ground fish, which use the huge tree-like organisms to hide from predators and to breed.

“Any sort of structure is really important,” said Kerry Griffin, who staffs the Pacific Fishery Management Council. “Rockfish like to hide in little nooks and crannies.”

The Pacific Fishery Management Council’s proposed ban would put almost the entire coast of Southern California, between Point Conception and the Mexico border up to 200 miles off shore, off limits to bottom-trawl fishing. It's meant to prevent the kind of ecological and habitat damage that corals and sponges have experienced further up the coast.

The Council is required by law to identify and protect habitat for key commercial fish species, and their decision came after seven years of study.

The Pacific Fishery Management Council voted to protect a huge swath of ocean off the Southern California coast from bottom-trawl fishing on April 9, 2018. The new protected area is in green. Areas previously protected are in orange. Courtesy Oceana

The proposed ban also gives scientists a chance to make new discoveries in an untouched ocean wilderness.

“We don’t even really know what’s down there!”, said Tom Ford, the head of The Bay Foundation. “The ocean is difficult to explore, and it’s expensive.”

Commerce secretary Ross is expected to review the council’s recommendation within the next six to 12 months. Griffin said he believes Ross is likely to approve the new conservation area.

This story is part of Elemental: Covering Sustainability, a new multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.