British Columbia

Salmon rescuers to blast rock to help fish spawn in Seymour River

The Seymour River Salmonid Society will be drilling and blasting the debris from a 2014 rockslide that has prevented salmon from spawning properly on the Seymour River.

Debris from a 2014 rockslide is preventing rare runs of coho and steelhead from spawning upstream

A massive rockslide came down into the Seymour River in December 2014, effectively blocking the stream. The Seymour River Salmonid Society's hatchery manager, Brian Smith, says some of the rocks are as big as houses. (The Seymour River Salmonid Society)

First, volunteers tried trucks. Now, it's time for explosives.

Salmon on the Seymour River have been unable to reach their spawning grounds upstream since a massive rockslide dumped rocks as big as houses into the North Vancouver, B.C. waterway in December 2014.

Last year, a concerted volunteer effort caught and trucked fish from the bottom of the river around the rockslide and then released the fish to spawn upstream.

Brian Smith, the hatchery manager with the Seymour River Salmonid Society, says the group will try to blast the rock away, because moving fish by hand was not a good long-term strategy.

"It was a gruelling endeavour and about 2,500 hours were put into it. We knew at the time that it wasn't sustainable."

A Seymour Hatchery volunteer holds a coho salmon. (Seymour Salmonid Society)

The blasting plan includes using low-velocity explosives and drills to break up the rock, and then waiting for a big flush of water to move the rock away in early fall.

"We are going to take our time and be very careful ... considering the safety of people and the safety of animals that we're trying to protect."

The cracked rock should also make it easier for the fish progeny to swim downstream.

"We'll go back in and assess, then do another round of drilling and blasting," Smith said. "We're looking at 3 to 5 year program, at about $1.2 million."

Tremendous effort

Until the rock is blasted away, the society will still be moving fish upstream by hand. They have installed a floating fish fence downstream from the debris which Smith says will help volunteers intercept adult fish more easily before they reach the rock slide.

While the project will take a lot of effort and resources, Smith says, it is needed. 

He says that through tagging they found that not one adult fish has been able to move past the rockslide, and since salmon always go back to spawn in the river they were born in and very rarely spawn elsewhere, the fish aren't surviving.

"Unfortunately, [many of these fish] die before they spawn."

The group will be working with a number of community partners including Metro Vancouver, the District of North Vancouver, Fisheries and Oceans Canada, and the Squamish and Tseil-Waututh First Nations.

The Seymour River Salmonid Society crew stands on its recently installed floating fish fence. The fence will hold adult fish further downstream from the rockslide, making it easier for volunteers to capture and truck the fish upstream around the obstacle. (The Seymour River Salmonid Society)

Salmon troubles

The efforts to preserve the Seymour salmon runs coincide with a vulnerable time for B.C. salmon.

The Seymour River supports rare runs of coho and steelhead salmon, Smith says.

In fact, he added, the steelhead summer run is only one of four summer runs in the entire Lower Mainland.

Meanwhile, the Fraser River is experiencing the lowest sockeye salmon run on record, which some experts say is because of the warmer than normal summer temperatures.

Recreational salmon fishing was banned on the Lower Fraser earlier this month, to conserve sockeye. 

With files from The Early Edition

To listen to the interview, click on the link labelled Salmon rescuers blast rock to help fish spawn in Seymour River