TORONTO (AP) _ Two American adventurers start out on the second half of a 2,500-mile trans-Arctic dogsled trek Thursday, hoping to shake a bit of bad luck and a lot of bad press.

Lonnie Dupre and Malcolm Vance spent the past few days in Cambridge Bay, a town of about 1,000 on Victoria Island in Canada's Arctic archipelago, gathering supplies and repairing clothes and equipment. Their final destination is Churchill, Manitoba, on the west coast of Hudson Bay.

The expedition, which started from Prudhoe Bay, Alaska, on Oct. 23, lost its main corporate sponsors and two other members in December after 19 of 36 sled dogs died. Animal rights groups condemned the adventurers for being ill- prepared and called on them to quit, but Dupre and Vance pressed on.

''I think the trip has been extremely successful so far,'' Dupre, of Buffalo, Minn., said in a telephone interview Tuesday. ''No one has ever traveled 1,350 miles from Prudhoe Bay to Cambridge Bay in the dead of winter.''

The Royal Canadian Mounted Police said it appeared the dogs died of a combination of bad luck and poor planning.

Some of the dogs were hearty Canadian Eskimo dogs. But others were a short- haired Alaskan crossbreed that were unable to endure the extreme cold and darkness of the Canadian Arctic winter and died of exposure.

The trip has three main goals: to follow the path of Knud Rasmussen, a Scandinavian explorer who traveled across the top of North America 50 years ago studying Eskimo culture; to collect plant and snow samples for pollution tests; and to make the first trip along the Northwest Passage by dogteam in winter.

''From the adventure standpoint, and the scientific standpoint, it's very successful, but we had a price to pay, a very large price,'' Dupre said, referring to the dogs. ''That's what people talk about the most ... I think the trip itself eventually will overshadow that.''

Dupre and Vance, of Shishmaref, Alaska, have averaged about 25 to 30 miles a day. They are heading next for Gjoa Haven on King William Island, the end of the Northwest passage.

After that, Dupre said, they have not decided whether to continue along the coast or head south overland to Baker Lake and then east to Hudson Bay.