QUINCY, Mass. (AP) – Eight dolphins were discovered early Sunday morning on a beach in Quincy in what scientists are calling an extremely rare mass stranding in Boston Harbor.

Passers-by discovered the dolphins at about 7 a.m. Sunday on Wollaston Beach. They were able to help two of the eight back into the water. The other six were dead.

“They had probably been high and dry since the low tide overnight,” said Tony LaCasse, a spokesman for the New England Aquarium.

LaCasse said no one at the Aquarium could remember a similar mass stranding of dolphins in Boston Harbor, although dolphin strandings have become more common on Cape Cod, especially in winter when the dolphins may be in search of food in marshy areas.

Four of the dead dolphins were taken to the aquarium to try to determine why they may have become stranded in Boston Harbor. Two were taken to the Woods Hole Oceanographic Institution.

One Jan. 4, two dolphins were found dead on Cape Cod beaches, bringing the total number of strandings that week alone to 17, eight of which were either found dead or had to be euthanized.