A major rock slide in B.C.'s Interior has created a waterfall on the Fraser River that is raising concerns about whether salmon swimming upstream will be able to reach their spawning grounds.

The slide occurred on June 21 near Big Bar, located some 40 kilometres northwest of Clinton.

Footage taken Wednesday from CTV Vancouver's Chopper 9 showed the white water being created by the underwater debris.

Fisheries and Oceans Canada and researchers who have been tracking the first salmon trying to make their way up the falls told reporters some fish have been recorded making it past the slide, but the murkiness of the water makes it impossible to tell what percentage are getting through.

DFO said an acoustic listening device placed above the slide has recorded several hundred fish—mostly Chinook and sockeye—that have swum past the obstruction.

"So far, we know that somewhere just below 700 fish from when we started counting, which was Friday night, to date have passed through our counting devices," said spokesperson Bonnie Antcliffe, "As noted, more work is required to look at what we anticipate we will see when we have further acoustic devices downstream."

If DFO determines that not enough fish are getting through, the department will look at other options to help the animals, including possibly installing fish ladders or capturing the salmon downstream and trucking them past the slide.

With files from CTV News Vancouver's Ben Miljure