“There’s a spout!” naturalist Celia Ackerman calls excitedly to the captain. “Behind the green buoy!”

It’s half an hour into a whale-watching cruise aboard the 95-foot American Princess, and we’re not in Hawaii or Alaska—we’re in New York Harbor, within sight of Coney Island and the Brooklyn shoreline.

About 30 tourists rush to the rail, and moments later, the distinctive outline of a humpback whale surfaces. Cries of delight echo round the boat. “I’ve never seen a whale,” says Milo Bartolotta, 15, who’s on holiday with his family from Florence, Italy. “So I am really excited.”

Such a sighting would have been almost unimaginable 20 years ago, when the waters around New York City were some of the most polluted in the world—a toxic stew of chemicals and garbage. Yet thanks to successful environmental policies—such as the Clean Water Act, the Endangered Species Act, and the Marine Mammal Protection Act—whales are back in the Big Apple.

Since 2011, when the nonprofit Gotham Whale recorded just five humpbacks, the number of cetaceans spotted off New York City has increased dramatically. By 2018, sightings had jumped to 272. This year promises to break that record, with 377 whales of different species already recorded in the waters around New York, most of them humpbacks.

So why the rebound? “I figured they were coming to see me,” jokes Paul Sieswerda, founder of Gotham Whale, which partners with American Princess Cruises, a commercial whale-watching company, to offer tourists a chance to see the behemoths from a safe distance.

In reality, as water quality improved and pollution levels fell, tiny oceanic life-forms such as algae and zooplankton bounced back, providing a crucial food base for a resurgence in menhaden, a schooling fish favored by whales.

You won’t find menhaden, colloquially called bunker, on a restaurant menu—they are oily and smell terrible—but they’re like caviar for whales, which gorge on them during the summer to build up their fat reserves before returning to the tropics in the winter to mate.

Peering over the side of the boat, we can see vast shoals of menhaden swirling around, bunched to protect themselves from predators into what fishermen call “bait balls.”

Another reason for return of the whales is laws protecting the marine mammals from hunting and other human activities—centuries of whaling, for instance, had brought the humpback almost to the brink. (Learn how humpbacks have made a stunning comeback in South Africa.)

It’s unknown how many and what types of whales historically plied the waters off New York City, but scientists believe they were an important top predator—and that their return to the biggest city on the Atlantic bodes well for the ocean’s long-term health.

Urban challenges

Of course, life near NYC isn’t always smooth sailing.

For one, whales have some competition for their favorite food: Commercial fishing operations along the eastern seaboard are now targeting menhaden on an industrial scale, turning the fish into animal feed and human supplements. Virginia-based Omega Protein, for instance, deploys spotter pilots along U.S. waters of the Atlantic and Gulf coasts to locate big schools of bunker.

Sieswerda is concerned that Omega Protein is fishing menhaden just outside New York City’s three-mile restriction zone, where the whales often congregate to feed; he’s mounted a petition to extend the zone to 200 miles. Omega Protein did not respond to a National Geographic request for comment about this petition.

In addition, New York City is now the busiest port on the eastern seaboard, with as many as 20 or more ships lining up to drop anchor and unload their cargo at any given time. This means collisions with whales—sometimes fatal—do happen. (Learn more about how ship strikes affect whales.)

“According to [the National Oceanic and Atmospheric Administration], there have been 103 known humpback whale deaths since 2016,” says Howard Rosenbaum, senior scientist at the Wildlife Conservation Society’s New York Aquarium.

“About 50 percent of these showed signs of human-related trauma, like ship strike or entanglement. Twenty-eight occurred in New York and New Jersey.”

Sounds of the sea

To counter this threat, Woods Hole Oceanographic Institution and the New York Aquarium teamed up to deploy a high-tech acoustic buoy named Melville, 22 miles south of Fire Island. Whales communicate mostly via sound, and each species has distinct calls (and even dialects).

When deployed in 2016, Melville immediately began to detect whale calls, data that is analysed and posted online with the hope that ship captains will take note of where the marine mammals are swimming and slow down accordingly.

“The buoy records what we call pitch tracks,” says Mark Baumgartner of the Woods Hole institution, who studies the data in his Massachusetts laboratory. “It’s a bit like having a magical device on your piano, so that as you play, it spits out sheet music. You could then take that sheet music to a musician, who will be able to tell you what you are playing.”

Curious Baby Humpback Whale 'Dances' With Mom and Divers This humpback whale and its calf were found playing off the coast of Tonga.

Melville—named for the author of Moby Dick, of course—has captured vocalizations of the little-seen, 65-foot-long sei whale, as well as one of the world’s most endangered whales, the North Atlantic right whale—so named because it was the “right” whale to hunt. With only about 400 of the animals remaining on Earth, this species is particularly vulnerable to any threat, including ship strikes. (Read about the recent deaths of four of North Atlantic right whales.)

In December, the Wildlife Conservation Society and Woods Hole will add two new buoys, to be funded by the energy company Equinor, which is developing a wind farm in the area. Baumgartner is concerned the wind farm’s construction could create noise, which can disturb whales by disrupting their communication.

"So we hope the real-time monitoring we can get from the buoys will help mitigate these effects," he adds.

'An amazing thing'

As the boat chugs back to where we started, in Far Rockaway, we take stock of the day.

Two whales. No breaching. And no lunge feeding, when a whale explodes upward out of the water, jaws apart, to gobble up thousands of bunker in one gulp.