For the first time in years the number of Chinook salmon returning to spawn in the Yukon River is above the minimum set out in a Canada-U.S. treaty, but there are still concerns about the health and future of the wild salmon population.

Biologists were predicting the lowest number of returning salmon ever this season and for the first time ever a complete fishing ban was imposed along the entire length of the river, through Alaska and Yukon, to allow the fish to reach their spawning grounds.

The Canada-U.S. fisheries treaty provides for a minimum 42,000 Chinook salmon to return to Canadian spawning grounds. Returning salmon are counted at a border sonar station on the Yukon River at Eagle, Alaska. This year is just the third time in eight years that the minimum goal has been reached.

So far more than 500 Chinook salmon have made it to the Whitehorse hydro dam's fish ladder.

Lawrence Vano, who manages a fish hatchery program at the fish ladder, is congratulating everyone who didn't fish this summer.

Chinook salmon Whitehorse

Chinook salmon pool at the Whitehorse fish ladder on Tuesday. So far more than 500 of them have made it to the fish ladder. Fishing of Chinook salmon was banned along the Yukon River on both sides of the border this year to try and give the population chance to recover. (CBC)

"I never, ever would have thought that they would actually agree to not fishing for at least a season," he said. "At least it is a starting point."

Fish ladder employees are selecting a few fish to be kept in tanks so their eggs can be collected and raised in the hatchery. 

Vano is concerned because so many of the fish returning are from the hatchery. Only a fraction are wild fish and males are outnumbering females by nearly three to one.

"Five years ago the run just wasn't as productive as other years so they knew that the female population was probably going to be a bit shy," said Vano.

"So we are being very careful on our brood stock collection. We want to make sure we get up on the spawning grounds."

Despite the high proportion of male and hatchery-raised fish, Vano is confident this years fishing ban will pay off five years down the road when the salmon from this year's spawners return to repeat the cycle.