Most Lower Frasier River Salmon Habitat Now Gone, UBC Study Finds

Up to 85% of historical salmon habitat on British Columbia’s Lower Fraser River is now gone, lost to over 1,200 barriers blocking fish from reaching streams and habitat, according to a newly released report by the University of British Columbia.

Salmon have lost access to the bulk of their historical floodplain habitat, the biologically rich wetlands next to a river or stream that typically harbor wildlife, according to researchers from UBC and the British Columbia-based Raincoast Conservation Foundation.

“Only around 101 square kilometers (under 63 miles) out of an estimated 659 square kilometers (about 409 miles) of historical floodplains remain accessible to salmon,” said Riley Finn, a research associate with the Conservation Decisions Lab at UBC and lead author of the study.

There are currently over 1,200 barriers preventing salmon from reaching some 2,224 kilometers of streams, he added.

“This loss is particularly critical for populations of coho and Chinook, which rely more heavily on these habitats for rearing, compared to other types of salmon,” he said.

Researchers found that up to 64% of streams are now off-limits to salmon because of dams, floodgates and road culverts blocking off important channels for migrating salmon, which spend a portion of their lives at sea, then return to their natal streams to spawn and rear their young.

“If salmon do not have sufficient habitat to breed and complete their life cycle, then none of the other conservation management actions we take will matter,” Tara Martin, a UBC professor of forest and conservation sciences, explained.

To reach their conclusions, the team studied historical vegetation records, old surveyor and topographical maps dating back to the 1850s, plus other records specific to the Lower Fraser.

“Given the magnitude of habitat loss in the Fraser, large-scale habitat protection and restoration is a key component in efforts to restore wild populations of salmon to the Lower Fraser, Martin said. “We are using these results to identify priority areas to remove barriers and restore salmon habitat to have the greatest benefits for salmon recovery.”

The report on lost habitat was released on Aug. 5, just one day after British Columbia fisheries officials announced $7.9 million in funding for seven projects under the British Columbia Salmon Restoration and Innovation Fund (BCSRIF).

Plans are for the Vancouver-based Pacific Salmon Foundation, a nonprofit dedicated to guiding the sustainable future of Pacific salmon and their habitat, to develop a set of climate action priorities for the fish, including research to improve genetic baseline data to better understand differences between distinct salmon populations.

Since the program’s inception in 2019, some 48 projects have been funded representing an investment of over $75 million in the future of wild Pacific salmon and the province’s fish and seafood sector.