Why whales are back in New York City

Kendra Pierre-Louis in Popular Science:

For the first time in a century, humpback whales have returned to the waters of New York harbor. And not just occasionally, either. They're coming in enough numbers that a company can reliably trot tourists out to the ocean—within sight distance of Manhattan’s skyscrapers—to see them.

“Because of the improvement of the water quality, algae and zooplankton have multiplied, giving good food for the menhaden [a small oily forager fish beloved by whales], which have returned in numbers that the fishermen say they have not seen in their lifetimes,” Paul L. Sieswerda told PopSci. Once a curator at the New York Aquarium, Sieswerda has since founded Gotham Whales, an organization that conducts tours and monitors the presence of whales, seals, and dolphins in NYC. “Our surveys show an exponential increase in the number of whales since 2011 when we first began our studies," he said. "Prior to that, whales were only seen intermittently."

While Sieswerda dates the presence of whales back to 2011, 2014 was the year that whales caught the attention of many New Yorkers: one especially charismatic whale was captured on camera. A humpback seamlessly parted the water's surface, maneuvering its forty-foot, forty-ton form so that it was floating perfectly erect. Although its tail stayed below the surface, its rostrum (or beak-like snout) and head stood proudly exposed. The incredible power and buoyancy of its pectoral fins kept it aloft in a slow and controlled motion that bore a striking visual similarity to a person treading water. Whales use this motion, called spyhopping, to get a better view of what's on the surface—like prey, or humans gawking at them from whale watching boats. This is a marvel to behold anywhere in the world; to see it in New York City, with the Empire State building glimmering in the background, borders on the fantastical.

More here.