NEW YORK, NY – Staggering numbers of whales are being sighted off New York City shores as vastly cleaner waters have caused a 540% increase in the numbers of the massive mammals in just eight years.

Experts at the Rockaway-based non profit Gotham Whale started tracking sightings in the area in 2010 – counting just five. Last year, they spotted an awe-inspring 272, almost all humpbacks. The rise is monumental and points to the success of environmental policies such as the Clean Water Act, the Endangered Species Act and the Marine Mammal Protection Act, Gotham Whale's founder said.

Paul Sieswerda, who worked as a curator at the New York Aquarium for more than 20 years before starting Gotham Whale, says lessening pollution in the Hudson River has also had a dramatic effect.

Artie Raslich/Gotham Whale "So the Hudson River, instead of bringing out pollution to the areas we see whales – the lower estuary and the area right outside the mouth of the Hudson – it's bringing nutrients," he said.

Those nutrients feed tiny algae that attract the fish Menhaden - a major humpback food source that's known as the "most important fish in the sea" for the amount of other animals they feed, according to Pew Charitable Trust's Mid-Atlantic Conservation Project. Gotham Whales recently kicked off its ninth season partnering with American Princess Cruises, providing New Yorkers the chance to see humpbacks from May 4th to November 3rd.

"The sheer size alone is incredible," Sieswerda said of the whales.

"They're like buses, and to think that's a living animal and to think that is has the power and grace to completely jump out of the water when they breach is a spectacle that I think is unique to the animal kingdom."

Archie Raslich/Gotham Whale Gotham Whale is able to identify individual Humpback whales from the underside of their fluke (tail), which serves like a fingerprint having distinct patterns and colorizations. The non profit is building a catalogue of the whales they see near the city, which is now up to 110 individuals.

The favorite of the bunch is a Humpback called Jerry – named after Jerry Garcia by the group's photographer Artie Raslich, a Grateful Dead fan. The animal was first seen from a boat named after the band's song "Ship of Fools" on what would have been Garcia's birthday.