The Whitehorse Rapids Fishway has installed underwater cameras to monitor the salmon pooling below the entrance to the fish ladder.

"We have two at the bottom and last year they weren't strapped in properly so they shook around and it was hard to see what was happening,” said Michelle McKay, manager of the Whitehorse Rapids Fishway.

“So this year they put them in some PVC pipes and a metal rod so it's easy to clean the cameras and makes it easy for the people to see."

As of Wednesday morning, 89 chinook salmon had passed through the fishway, the longest wooden fish ladder in the world. Dozens more are pooling in the rapids below, before they make the climb.

McKay said she expects to see about 500 salmon pass through the fishway before the annual run ends. Last year 1,500 fish made it through the ladder.

The Whitehorse Rapids Fishway was built more than 50 years ago to allow salmon to migrate past the hydro dam at Whitehorse to reach their spawning ground. It is owned and operated by the Yukon Energy Corporation.