Humpback whales and great white sharks are surging in numbers in the waters around New York City this summer, in a wildlife bonanza that is delighting naturalists, environmentalists and fishermen – if not necessarily bathers.

Off New York and New Jersey, some of the largest creatures in the ocean are being spotted in greater abundance than has been the case for decades. Paul Sieswerda, head of the Gotham Whale volunteer marine wildlife tracking group, believes the increasing abundance of whales around the Big Apple is largely prompted by cleaner waters that have encouraged huge rises in the populations of fish which the whales eat.

Sieswerda takes boat tours to locations where giant humpback whales can be seen feeding – with the iconic Manhattan skyline in the background.

“I would say it’s only about four miles from the Statue of Liberty,” he told the Guardian.

Gotham Whale counted 29 whales, all humpbacks, in New York waters from the start of the feeding season in the spring to the end of July 2014, compared with 43 for the whole 2013 season, 25 in 2012 and five in 2011.

Sieswerda, a former curator at both the New York aquarium and the New England aquarium in Boston, keeps records of whale sightings with a team of trained volunteers, identifying individual whales by their unique tail markings.



His team has seen humpbacks “lunge feeding”, where the whales rise up under giant shoals and take hundreds of thousands of pounds of fish into their mouths in one gulp, filtering out the seawater through their baleen grills and swallowing the fish.

A humpback whale lunge feeding, showing great expansion of throat. Photograph: Artie Raslich/Gotham Whale Photograph: Artie Raslich

Sieswerda praised the gradual cleaning up of the Hudson river, which flows into New York harbour, for bringing to the sea nutrients which feed the plankton that feed the fish the whales eat.

“The river used to bring nothing but pollution but in the last five years or so there is cleaner water, more nutrients and less garbage,” he said, adding that other conservation and protection measures elsewhere in the region have also improved the ocean waters considerably.

“My boat captain says New York is the new Cape Cod,” Sieswerda said. Gotham Whale runs research and tourist trips from Breezy Point, Queens.

The surge in whale numbers can also lead to problems – in May, after a sei whale was hit by a cruise ship and dragged up the Hudson River, increased numbers of collisions between whales and ships were reported in the New York and New Jersey area. Last month, the US government’s decision to open the Atlantic seaboard from Florida to Delaware, south of New Jersey, for oil prospecting using sonic cannons also caused concern.

Whales and great white sharks are most commonly spotted off the Massachusetts and Maine coasts in summer and have been increasing there in recent years. But improved food supplies in the waters around New York and New Jersey appear to be attracting more sharks and whales to linger, instead of heading north for the summer feeding season.



Menhaden scatter to escape a feeding whale, in waters south of New York City. Photograph: Artie Raslich/Gotham Whale Photograph: Artie Raslich

From New Jersey to Cape Cod, in Massachusetts, fishermen have reported increased instances of seeing and reeling in great whites and other sharks. The National Oceanic and Atmospheric Administration has reported a surge in numbers on the east coast but has yet to record detailed data. However, the agency’s most recent research, carried out off the California coast, showed great white numbers rising an estimated tenfold, after decades of decline accelerated if not solely caused by a rise in shark hunting inspired by the 1975 film Jaws.

In June, off Long Island, New York, three great whites were hooked in a week; sightings off New Jersey have also increased. In one such incident, fishermen reeled in a baby great white – which still weighed 80lbs – off Rockaway Beach in Queens. They released it and spotted its mother swimming nearby.

Beachgoers, however, have not been threatened, with the closest sighting to land still being a mile offshore.

“Shark attacks are so rare even in waters where humans and sharks are known to coincide,” said Sieswerda. “I know it’s the start of [Discovery’s] Shark Week, but that doesn’t concern me.”

A whale dives, with Manhattan’s One World Trade Centre, also known as the Freedom Tower, in the background. Photograph: Artie Raslich/Gotham Whale. Photograph: Artie Raslich

Dolphins and seals are also on the rise. Sieswerda personally monitors a colony of harbour seals near his home in the New York City borough of Staten Island, which have increased to around 66 this year from just 10 in 2006.