PRINCESS ROYAL ISLAND, British Columbia, Canada — Paul Paquet is an expert on bears and wolves but says salmon are the most critical species in the Great Bear Rainforest.

"The real key to the temperate rainforest is salmon; virtually everything depends on them," said Paquet. He spoke quietly as we stood in the forest beside a spawning stream, hoping a rare white Kermode bear would show up for lunch.

"If you went to the tops of these trees, you'd find nitrogen from the salmon," he said. "They came 4,000 miles from Asian waters, took them two to four years, depending on species. Lot of people think the ancient forests were so large because of that pulse of nitrogen that it gets every year. The wolves and bears are sort of the fertilizer dispensers in the forest.

"But those fish also are bringing contaminants back, toxic chemicals, that they pick up in their migration. Now those are starting to show up in the animals — the bears and the birds."

The Great Bear Rainforest stretches from the northern tip of Vancouver Island to the Alaskan Panhandle along the west coast of British Columbia. The area is home to the largest remaining tract of temperate rain forest in the world. It also boasts pristine river valleys, many of which have gone untouched by the logging industry, so far.

The area has served as Paquet's laboratory for more than a decade because it has populations of wolves, grizzlies and black bears, including the genetic combination that produces the cream-colored Kermode, or Spirit Bear.

"They are a black bear, but 10 percent of the population is white," Paquet said. "They're geographically limited to just a few islands in this area. There are white black bears that appear elsewhere, but not with this consistency. Maybe one in every 100 generations."

In his wolf studies, Paquet abides by the wishes of the First Nations peoples and forgoes trapping and collaring in favor of a less intrusive method — he collects scat and examines the DNA. From DNA, he can identify the individual animal and tell much about its life.

"The wolves, in particular, here are turning out to be genetically unique," he said. "They have retained their genetic diversity; they have a lot of genes that have not been lost over the year because of persecution.

"Wolves in North America have lost 50 percent of their genetic diversity. When you limit genetics, you get the effects of inbreeding."

His research found two other interesting behaviors: The wolves move between the islands, sometimes swimming as far as eight miles in the open ocean. And they eat salmon.

"They go into the streams and a single pack will take 200 fish a night," he said. "We didn't expect to see fish-eating wolves, which is kind of embarrassing because the First Nations peoples have known this all along. That information gets lost and we publish it, and get credit for it."

Paquet pointed out that logging and commercial overfishing are threats to the salmon populations, which he said are showing distressing signs of decreases. "We don't know what the consequences are, but it's frightening," he said.

While the white bears are protected, the black bears, which may carry the rare gene, are open to trophy hunting. There are proposals to create a Spirit Bear Park, which would center on Princess Royal Island and encompass up to 1,000 square miles, to prevent logging and hunting in the Kermode's stronghold.

"There's a lot of objection to hunting," Paquet said. "The First Nations don't hunt bears or wolves."

A couple of noisy ravens flew by, and Paquet returned to his position watching the stream.

"The activity by the ravens often indicates the presence of bears or wolves," he said.