Plymouth Harbor pilot whale dies; mystery remains on why whales came north

By Martin Finucane, Globe Staff

A short-finned pilot whale that ventured from its usual home in warmer waters to Plymouth Harbor has died, the New England Aquarium said.

The ailing whale, which was in poor condition, died Thursday afternoon as a staff veterinarian prepared to euthanize it in shallow waters in Plymouth Harbor, the aquarium said in a statement.

The aquarium said it was believed that the whale was one of three that stranded in Duxbury on Columbus Day. Two of those three were refloated, while one died on the beach.

The whale was an unusual visitor, normally a denizen of waters off the southeastern United States and the Gulf of Mexico, the aquarium said. Before the strandings on Columbus Day, there had never been another documented case of the species stranding in the state.

Another short-finned pilot whale was stranded and died on the day after Columbus Day on a Truro beach, bringing the total of dead pilot whales in 10 days to three.

It’s not clear why the whales came north. One theory is that a large pod came north in late summer and left as water temperatures dropped, leaving stragglers behind. Another theory is that a smaller cluster of young adults rode an eddy of warm water north from the Gulf Stream, the aquarium said.

Aquarium officials asked anyone who sighted pilot whales in Cape Cod Bay in the first two weeks of October to contact them.