Humpback Whales Flock to Boston Harbor in the Hundreds

Whale watching in Boston Harbor is exceptionally exciting this month, with hundreds of humpback whales flocking to the coastal waters, a hefty increase to the usual two or three that are spotted.

On Wednesday, 40 whales were spotted on a single three-hour tour to Stellwagen Bank, known as one of the world's most active marine sanctuaries, The Boston Globe reported.

"The past few weeks have been exceptional," said Laura Howes, director of marine education and conservation for whale watch trips run by Boston Harbor Cruises.

Large numbers of an eel-like fish called the sand lance, or sand eel, are turning the waters into a "whale feeding ground," Howes said, according to the Associated Press.

Stellwagen Bank, an underwater plateau about 25 miles east of Boston, just north of the tip of Cape Cod, attracts sand lances with its sandy bottoms. The eel-like fish were absent last year, and scientists cannot explain why this time around they have returned in full force.

"We just don't know too much about them, and we really need to," said Dave Wiley, a scientist at the Stellwagen Bank National Marine Sanctuary who has been studying the sand lance.

It's hard to say exactly how many humpbacks have shown up, but over the years there have been about 900 documented sightings, according to The Globe.

These 40-ton animals use teamwork to round up the tiny prey, blowing bubbles to scare them into tighter groups. A humpback may eat as much as a ton of sand lance each day.

Sand lance are a critical component of the oceanic food chain, and apparently they make for an exciting whale watching experience.

A Provincetown group saw 12 humpbacks Wednesday, and a boat out of Gloucester spotted 15, including a breaching calf.

"It's been an exciting few weeks," Howes said. "It's a great time to come out."