Millions of wild salmon make their way out of the Lower Fraser River and into the Strait of Georgia each year, but 2022 is the first time in more than 100 years their natural path hasn’t been obstructed.
In March, the Raincoast Conservation Foundation led a project to breach the North Arm Jetty, a seven-kilometre long barrier stretching from the Vancouver International Airport to the University of British Columbia. Tucked behind it is a brackish marsh habitat, vital for juvenile salmon to rear and feed in before transitioning into the ocean’s salty water.
Dave Scott, biologist and research and restoration coordinator for the Fraser River estuary, said before the jetty was constructed, salmon relied on the area to slowly shift from fresh to salt water. With the structure in place, they were forced to dive straight into deep ocean water – something Scott described as “physiologically challenging.”
He said the North Arm Jetty is one of numerous barriers constructed around 1915 after settlers decided to dredge and deepen the river entrance to allow for the easier movement of ships. The jetties were created to keep unwanted sediment in place.
“You can imagine in 1915 they didn’t really know, or weren’t focused on, how it would impact the movement of fish,” Scott said.
He said since they created a 30-metre opening in the jetty in March, the Raincoast Conservation Foundation has already seen juvenile salmon passing through the breach. This kind of immediate success, he said, is rare.
Because the Lower Fraser River and estuary have been so highly modified by humans, Scott said more than 80 per cent of tidal marsh habitats are lost or remain inaccessible to juvenile salmon.
The conservation group made two other breaches of the river’s Steveston Jetty in 2019 and plan to make another two on the North Arm Jetty in the coming years.
“This will hopefully give these fish a fighting chance on their way into the open ocean,” Scott said in a news release.