By Lauren Keiper
BOSTON (Reuters) - Researchers in Massachusetts say they are on track to spot a record number of endangered right whales in Cape Cod Bay and nearby waters.
So far this season, which stretches from January through mid-May, more than 200 right whales have been sighted, accounting for nearly half of the known species population.
The total thus far is the same number tracked during the entire 2010 season, said Laura Ganley, flight coordinator for the right whale studies program at the Provincetown Center for Coastal Studies.
Aerial tracking on Tuesday resulted in 101 individual whale sightings, the most on record for a single flight.
With another aerial survey planned for Friday and at least a handful more after that, Ganley said researchers expect their North Atlantic right whale count to rise.
"Seeing so many right whales so close to shore is very important to researchers," Ganley said.
The whales have even been spotted from the Provincetown beaches, just 50 or 100 yards off the coastline where the water deepens quickly.
Right whales are the most endangered large whales in the North Atlantic, with about 473 left in the population, according to experts.
Researchers can identify the individual whales by the rough skin and so-called whale lice pattern on their heads, Ganley said.
The massive mammals -- most adults measure around 50 feet in length and weigh up to 70 tons -- are lured to the waters off Cape Cod to feed on zooplankton, which is most abundant in the spring. New whales have been seen among recognizable returning whales, researchers said.
"They wouldn't be here if the food wasn't great," said Erin Burke, a specialist in protected species at the Massachusetts division of marine fisheries.
In mid-April, the whales feast on a particularly fat, oily plankton near or just below the water's surface, increasing their risk of being hit by passing commercial or recreational boats.
Vessel collisions account for about half of right whale deaths caused by humans, with the remainder from entanglement, Burke said.
Once the food supply runs out, in perhaps another week, the right whales are expected to move on to summer and fall feeding habitats in the Gulf of Maine.
(Editing by Barbara Goldberg and Peter Bohan)