The verdict is in: after sifting through photos sent to the New England Aquarium by people who have spotted seals swimming in the Charles River since late March, experts say they’re “quite confident” that more than one pinniped has been visiting the area.
“We compared the photos among all of our staff who work with seals,” Aquarium spokesman Tony LaCasse said in an e-mail Monday. “They were unanimous that it was more than one seal, as one was quite light-colored with spots while the other was dark and has a facial feature that we call a mask.”
Seal sightings have been reported up and down the Charles River. One was sighted as far away as the Boston University Bridge. They’ve been caught lounging on docks, soaking in the sun.
Advertisement
Aquarium experts say the seals are gaining access to the freshwater river through the locks of the Charles River Dam. Workers from the state Department of Conservation and Recreation open and close the gates of the three parallel locks as part of their daily tasks. The locks separate the river basin from the Boston Harbor on the other side.
LaCasse has said the seals have likely learned that if they wait patiently at the gates, having arrived there by following spawning fish, they can swim upstream to gorge themselves on large fish that are easier to catch than in the ocean.
“Last weekend, the Museum of Science staff shot a great picture of a seal in the Charles swimming with about a 4-pound carp in its mouth,” LaCasse said.
On Sunday, a seal was again seen swimming near the locks. At the time it was unclear if it was the same seal that had been observed by multiple people in recent weeks, or if it was one of several who have decided to take advantage of the lock system.
Advertisement
But LaCasse put the mystery to rest.
“We would not be surprised if there were multiple adult harbor seals working the locks and the lower basin of the Charles,” LaCasse said.
Steve Annear can be reached at steve.annear@globe.com. Follow him on Twitter @steveannear.