In the ocean off South Carolina, researchers spotted something attached to Slalom the North Atlantic right whale, and for once, it was a good thing. She had a baby.

A sigh of relief spread across the community of Atlantic whale watchers who know critically endangered right whales are as likely to die as they are to give birth. On her path to motherhood at age 39, Slalom — named for a series of callous-like patches on her head that swoop like a ski slope — has survived at least six fishing net entanglements that are known to kill whales.

Over the past decade, the right whale population fell from more than 500 in 2010 to about 335, largely because of entanglements, boat strikes and slicing propellers. Fewer than 100 adult females remain. By comparison, endangered southern right whales that swim between Australia and South America number in the thousands.

“If you look at a graphic of what the North Atlantic right whale population looks like, it can seem like there’s no hope. It’s really alarming how quickly the population has declined in the last 10 years,” Philip Hamilton, a senior scientist for the New England Aquarium, said in an interview Friday.

If only every whale were as resilient as Slalom.

Slalom is a survivor built from tough family stock. Her mother, Wart, gave birth to seven whales, including a brother that swam more than 100 miles up the Delaware River at 11 months old and a sister that was born in Cape Cod Bay, both rarities, according to the aquarium. Whales younger than a year don’t normally power up rivers, and whales are normally calved in warmer southern waters between Cape Fear, N.C., and Cape Canaveral, Fla.

And then there’s Slalom, a whale that first cast off a fishing net at age 13, then again four years later. She survived them four more times, including ages 25 and 34. Scientists determined that she had been entangled based on how the nets marked her hide. Her most recent entanglement gouged her deeply, Hamilton said.

Slalom has at least one other offspring that is legendary. Mogul swam all the way to Iceland one year and to France and Newfoundland the next year, according to the aquarium. Her children and grandkids endured 17 fishing net entanglements plus two vessel strikes. A grandson, Junction, has two sets of propeller wounds on his back.

Here’s how the right whale got its name. Commercial whalers thought the species was the perfect prey, the right whale to hunt because they moved slowly and tended to float after being killed. In the late 1800s, they were stalked until there were virtually none left.

Last year an international group of governments and scientists declared that the North Atlantic right whale is “one step from extinction.” The group coincidentally released a study about a month after President Donald Trump lifted restrictions on commercial fishing in a key area of the whale’s habitat near Maine.

Between 2012 and 2016, 30 Atlantic right whale deaths were confirmed as human-caused, according to the International Union for Conservation of Nature report, all but four linked to fishing gear. The deaths drove a 15 percent decline in the population.

“This status change is a call to arms: unless we act decisively to turn the tide, the next time the right whale’s Red List status changes it will be to ‘extinct,’ ” Jane Davenport, a senior attorney for Defenders of Wildlife, said at the time.

Ahead of a campaign where he sought votes in Maine, Trump signed a proclamation that opened the Atlantic Ocean’s only fully protected marine sanctuary to commercial fishing, dismissing arguments that crab traps, fishing nets and lines dangling hooks were harmful.

Trump’s order allowed fishing to resume at the Northeast Canyons and Seamounts Marine National Monument off the coast of New England. The Obama administration had closed off nearly 5,000 square miles of ocean in 2016 to allow marine life to recover from overfishing. In October, President Biden issued a proclamation that essentially restored Obama’s order.

Right whales are sometimes called urban whales because they hang out in industrial waters where large vessels roam, particularly off Jacksonville, Fla., and Brunswick, Ga.

Federal legislation forced boats in channels frequented by whales to slow down. But fishing gear in the areas, which increased in both number and strength, is a much larger problem because it can show up anywhere.

Right whales don’t produce babies as quickly as most mammals. Their pregnancies last a year, and under normal conditions there are three years between pregnancies. “But now,” said the National Oceanic and Atmospheric Administration, “females are having calves every six to 10 years on average.”

Stress caused by entanglements is one reason, NOAA said, along with underwater noise and vessels, making it hard to replenish a dwindling species. NOAA called right whales “one of the world’s most endangered large whale species.”

Climate change driven by human activity is yet another threat. Over the past decade, as oceans warmed, “right whales have changed their distribution patterns, likely in response to changes in prey location,” NOAA said. They followed zooplankton and other prey into waters with fewer protections from vessel strikes and entanglements.

“It’s really, really important to stress that this species has come back from even lower numbers in the past and it can adapt,” Hamilton said. “We just have to give them the opportunity. We have to stop killing them and causing them serious harm.”