Dan Reiner

dreiner@lohud.com

Through early January, reporters will be looking back at and following up on stories and topics that were the most popular with our readers in 2016, according to metrics on lohud.com. This story is part of that series.

In late July, a few fishermen on Long Island Sound reported a humpback whale feeding a few miles off the shore of New Rochelle.

The sighting — one of many in the Sound this summer — was the second consecutive year that whales were reported in that area.

Fast forward to last month, when a humpback that had frolicked off Manhattan made its way up the Hudson River, throwing both jaded New Yorkers and whale experts for a loop.

With such an increase in whale sightings around the Lower Hudson Valley, we asked: Why are some of Earth's largest mammals visiting local waters more frequently?

Here's what we found out:

These whales aren't lost

Paul Sieswerda, a whale researcher and president of Gotham Whale, a nonprofit group that studies whale behavior near New York City, said it is unusual for the creatures to leave the open ocean, and especially to venture into a body of water such as the Hudson River.

He said the first concern when a whale makes such a journey is that it might be injured, debilitated or lost.

However, when last month's humpback, nicknamed Gotham, traveled up to the George Washington Bridge just south of Yonkers, observers found that it seemed to be behaving normally.

So maybe he just had the urge to wander.

LONG ISLAND SOUND: Humpback whale spotted off New Rochelle

HUDSON RIVER: Whale spotted south of Yonkers

"These humpbacks seem a bit more adventurous," Sieswerda said. "We see them in the shipping channel feeding and it seems very likely that Gotham chased fished into the harbor, up the river and went back out."

John Lenzycki, Curator of Animals at the the Maritime Aquarium in Norwalk, Connecticut, said whale migration is dependent on several factors, including water temperatures and the gender, sexual maturity and age of the whale. He said groups tend to move together, and it's more difficult to track an individual whale.

"Whether they’re migrating from the feeding grounds during the summertime from New England and up to Nova Scotia and the Arctic down to the Caribbean and the West Indies during the wintertime to calve and mate, those are grand movements that are well understood," Lenzycki said. "But small, individual movements – whether they move into a particular body of water or not – really can’t be explained definitively."

He said cleanup efforts in both the Long Island Sound and the Hudson River have likely contributed to more whale activity in recent years. Efforts such as Soundkeeper's Pump Out Program and the Environmental Protection Agency's Hudson River Cleanup have made the local bodies of water popular breeding grounds for menhaden (also known as bunker) and bluefish, the types of fish humpbacks most often feed on.

Whales are sticking around more

Gotham Whale, the group headed by Sieswerda, uses The American Princess as its research vessel. Based out of Rockaway, the adventure cruise ship was used recreationally to watch seals and dolphins in the New York Bight — the area of the Atlantic south of New York City and Long Island — until 2010, when the ship's captain heard reports of a whale, Sieswerda said.

In 2011, there were three sightings of five whales in the Bight. Since then the number of whale sightings has more than doubled every year, Sieswerda said. As of early December, he said there had been at least 100 whale sightings in New York waters this year alone.

Sieswerda said a whale watcher is "about as likely to see a whale in the New York area" as they would be off New England, an area the cetaceans are known to frequent. He said there's about a 90 percent chance of seeing a whale during the summer months in New York.

"That just wasn’t the case even 10 years ago," Sieswerda said.

More whales in 2017?

The whales are sticking around longer, too.

Five years ago, the whale watching season lasted from May until early October. This year, the American Princess' last cruise was Dec. 4, when researchers were able to track Gotham the whale still just three miles off Rockaway Beach.

Lenzycki cautioned that fishermen and recreational boaters must heed Coast Guard warnings and National Oceanic and Atmospheric Administration regulations meant to keep the whales and other sea life safe.

“One of the bigger threats to these guys right now, with the health of the Sound and our oceans improving, is us and the amount of traffic coming in and out of the New York Bight," Lenzycki said. "Several animals have been struck by boats right off of New York and that’s always a bigger danger for them."

Sieswerda said a whale in the Hudson can be difficult for large ships and barges to avoid, so it's important for those vessels to slow down when alerts are sent out. Meanwhile, fishernen in the Sound should mind their nets.

He said the See a Spout, Watch Out! program works with boaters to protect whales.

While it's difficult to predict whale activity, Lenzycki said a cleaner Sound is good news for those hoping to catch a humpback breach. He said the rising presence of seals, sea turtles and other whale species — including belugas seen off Fairfield, Connecticut, this year — are signs of good things to come.

“The trend is evident," he said. "We’re definitely seeing more of them."

Twitter: @reinerwire