As far as underwater photos go, the sonar images acquired by scientists from the ocean floor off Haida Gwaii aren't as dramatic as those of the recently found Franklin ship.

But for a team of archeologists who for decades have been searching for proof of the earliest human presence in North America, the images of a cluster of rocks and unnatural rectangular shapes are just as important as the Arctic discovery that made world news two weeks ago.

"The Franklin thing is amazing … but we knew the ship was there somewhere and we knew the basic story [of the ill-fated British expedition]," said University of Victoria archeologist Quentin Mackie. "Our stuff is different. It's a lot older and we know nothing [about how it got there]."

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The line of rocks, he said, is at least 13,700 years old, which would make it the oldest fishing weir discovered in the world. And the rectangles marked deep on the sea floor in Juan Perez Sound are most probably the sites of ancient camps of the same age.

"We are the first people to see that … It's like outer space imagery but you know people have been there, not just passing through, but that was their homeland," he said. "It is like a voyage of discovery for us to see that lost world that people have not looked at for so long."

If dredging by a remotely operated vehicle confirms the authenticity of the sites, it would be the earliest evidence of human habitation in Canada and the find would shed new light on where and when the first people came to the Americas.

"It's really incredible to look at that and think wow, people were down there walking around … and those places had names and were part of their world … and you are looking at it for the first time that anyone's looked at it in [over] 13,000 years," said Mr. Mackie of the sonar images.

He and his colleague, Daryl Fedje, who works jointly with UVic and the Tula Foundation research centre, are leading a project, supported by Gwaii Haanas National Park Reserve, that is probing hundreds of metres beneath the sea along the east coast of Haida Gwaii.

The area they are searching is submerged now, but thousands of years ago it was lush, rolling landscape above sea level that would have provided a migration corridor for both game animals, and the first peoples who came from Asia over the Bering land bridge. There is a debate over whether those humans travelled south via an interior corridor between glaciers, or along the Pacific Coast.

Archeological digs on Haida Gwaii put humans on the islands 12,700 years ago. But Dr. Mackie and Dr. Fedje have long argued that 16,000 to 17,000 years ago humans were likely using the landscape that's now deep under Hecate Strait. They have been lacking hard proof, however.

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Mr. Mackie is hoping the find will lead them to the kind of evidence they have been seeking.

The sites were located using a 3.5 metre, $1.5-million autonomous underwater vehicle under the direction of UVic mechanical engineer Alison Proctor, who used the AUV in 2012 during the search for one of John Franklin's ships.

Mr. Mackie said the AUV was programmed to "fly" down submerged valleys following old river beds, because that's likely where humans would have had salmon fishing sites.

Several promising "targets" were located, including what appear to be cuts in the side of hills where shelters might have been built. The archeological team is planning to go back next summer with a remotely operated vehicle because the sites, at up to 122 metres underwater, are too deep for the archeologists to dive on.

An ROV "can hover and you can put a lot of power down there so we can run some big search lights and photograph it," he said.

Dr. Mackie said the ROV can be rigged with a scoop or dredge that could dig for tools, spear points and other small items.

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"If you can closely target the place where the tent was, there should be lots of artifacts," he said.