A new marine national monument in the Atlantic Ocean aims to protect one of the most biodiverse spots on the planet from overfishing.

Located 130 miles off Cape Cod, the area spans more than 3 million acres and is part of the Biden administration's plan to conserve at least 30% of U.S. lands and waters by 2030.

Keith Shannon, Northeast chief of public affairs for the U.S. Fish and Wildlife Service, called the monument a "living laboratory" of pristine ocean habitat.

"Dolphins, multiple whale species and sea turtles and seabirds," Shannon outlined. "It's considered the Serengeti of the sea. There's so much wildlife out there."

Officially called the Northeast Canyons and Seamounts Marine National Monument, Shannon said it contains areas deeper than the Grand Canyon and taller than the Rocky Mountains, and will be safeguarded for years to come.

Debate over how to manage this vast marine environment has been ongoing. Former President Donald Trump lifted restrictions on commercial fishing in the monument area in 2020. The Biden administration reestablished protections one year later, in a move praised by environmental groups and condemned by fishermen, who said it would put more people out of work.

Shannon pointed out the new monument management plan helps ensure the unique area is protected from the harms of overfishing while the larger ocean ecosystem benefits.

"That should allow for species that are fished to come into the monument waters, breed and create more species in the areas outside the monument," Shannon explained.

The monument contains an abundance of phytoplankton, fish, squid and shrimp that serve as vital links in the marine food chain. New federal data show while some recent progress has been made in rebuilding fish stock in U.S. waters, nearly 50 species including Atlantic cod and mackerel remain overfished.

The public comment period is now open on California's new framework for deciding which managed areas within coastal waters meet the definition of "conserved," and where protection improvements need to be made.

California's goal is to preserve 30% of state lands and waters by 2030. The Ocean Protection Council released science-based guidelines this week on what counts as "conserved."

"An area is considered a conservation area if the lands and coastal waters are durably protected and managed to sustain functional ecosystems, both intact and restored, and the diversity of life that they support," said Jos Hill, project director at the Pew Charitable Trusts.

People can weigh in on the process at a series of upcoming workshops in Arcata, Monterey and San Diego. The Ocean Protection Council will also hold two webinars this summer and will accept feedback by email.

Hill said the new framework will be used by the state to evaluate protections in marine-managed areas. The state's "30-by-30" policy sets goals to improve biodiversity, public access and climate resilience.

"The stakes of failing to protect nature are high, and the loss of biodiversity undermines the ability of ecosystems to function and support a healthy environment," Hill said. "And this is particularly important in a changing climate, in which loss of biodiversity reduces nature's resilience to change."

The evaluation criteria will be finalized in the fall and the preliminary decision on which places qualify as conservation areas will be presented in December.

Support for this reporting was provided by The Pew Charitable Trusts.

Groups in Connecticut are preparing to celebrate World Fish Migration Day on Friday.

The biennial event celebrates migratory fish species and their importance. It also highlights challenges these species face, such as climate change. Warming waters make it harder for them to survive.

Rhea Drozdenko, a river steward with the Connecticut River Conservancy, noted that planting trees on river banks can reduce water temperatures. She said dams also pose a challenge for fish.

"They are essentially blocking off a river," she said, "so fish that might have historically been able to go far north, up through our watershed, now that there's dams there, they are now blocked. And so, now they have smaller and smaller habitats at their disposal."

She said conservation groups advocate for safer passage with fish ladders and fish elevators at the dams. Another way is removing so-called "deadbeat dams" that no longer serve an economic use and impede fish migration.

More information about events and getting involved is online at worldfishmigrationday.com.

Habitat neglect is another problem for migratory fish species. Steve Gephard, a Connecticut River Salmon Association board member, said he has found that if the habitat isn't suitable, migratory fish won't prosper. He said work is being done to restore important habitat areas.

"In some cases, it means putting rocks back in, putting woody debris back in, revegetating the flood plain, putting some curvature in the stream," he said. "A lot of streams, as they've gone through human areas, have been channelized."

Some habitats get degraded through industrialization and by clear-cutting forests. Data show hundreds of miles of fish passageway reopened between 1999 and 2018. If pathways for fish migration open up by removing dams, Gephard said, environmental groups have to ensure healthy habitat is there for these fish to return to.

New England fishermen and environmental groups are working to prevent the growth of industrial-size fish farms in U.S. open waters.

They said federal legislation known as the "AQUAA Act" would permit so-called "floating feedlots" similar to land-based dairy and poultry farms, known to use heavy amounts of pesticides and antibiotics.

James Mitchell, legislative director for the advocacy group Don't Cage Our Oceans, said there is no way to contain the chemicals or tons of untreated fish waste created.

"In fact, the whole reason for it is to rely on Mother Nature for its ecosystem services, to wash away the pollutants from the fish themselves so that they don't go belly up," Mitchell pointed out.

Backers of large-scale aquaculture argued it is needed to feed the world but studies show such farms often produce fewer fish than the number of wild fish taken from the ocean to make fish food.

Maine's abundant coastline and history of working waterfronts make it an ideal place for an aquaculture business, and numerous small-scale shellfish and marine plant farms are boosting local economies. But commercial fishermen say the growth of large, foreign-owned fish farms endangers both the ocean and their livelihoods.

Jason Jarvis, commercial fisherman and board president of the North American Marine Alliance, said aquaculture should be locally owned and low-impact.

"I think if we had multiple, small-scale aquaponics systems -- compared to large, industrial-size aquaculture -- I mean, it's a big difference in who benefits and how you benefit," Jarvis explained.

Jarvis noted it is the small- and medium-scale fishermen feeding their communities who keep working waterfronts alive. He added there is no guarantee in the AQUAA Act farm-raised fish would stay in the U.S., which already imports more than 90% of the seafood it consumes.