CHARLESTON, S.C. (AP) — The great white shark known as Mary Lee is headed north again after spending a number of weeks this winter along the Southeast coast.

The 3,500-pound shark was off Long Island, N.Y, on Thursday. Earlier, Mary Lee traveled as far south as Jacksonville Beach, Fla.

Shark researcher Chris Fischer says scientists know little about great whites and they are not quite sure why Mary Lee headed north so quickly.

Mary Lee and a second great white, Genie, were tagged in September. Genie headed south but because she doesn’t surface as much, her travels are less well-known. She was off the coast near the Georgia-South Carolina line earlier this month.

Fisher is the founder of OCEARCH, a nonprofit dedicated to studying great whites and other large marine species.