The Fraser River, historically considered to be one of the greatest salmon producing rivers in the world, is British Columbia’s longest river, flowing 854 miles out to the Strait of Georgia, just south of the city of Vancouver.
While the entire Fraser watershed is essential to salmon, the Fraser estuary is of utmost importance. It provides a migratory corridor for salmon populations aimed at far-reaching spawning sites, prime habitat for other salmon populations that don’t migrate into the river but spawn there instead. It is also vital rearing habitat for out-migrating salmon smolts.
Because of these historically abundant salmon populations returning to the Fraser in the spring and summer seasons, the fish-eating Southern Resident orcas were drawn into the Salish Sea during those seasons, spending their time foraging on salmon around the San Juan Islands, north to the Fraser River Delta. Summer field researchers in the 1970s and 80s could accurately estimate the arrival and departure of orcas timed with the Fraser’s seasonal runs of salmon.
In the last ten to twenty years, however, changes in Southern Resident foraging patterns, pod structure, and movements have occurred as salmon numbers continue to dwindle to just a fraction of their historic numbers.
More than half (33) of Fraser River salmon populations have been greatly reduced given their former abundance. 46 of the 54 unique populations have been evaluated by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) resulting in 36% being classified as endangered, 15% as threatened, and another 13% listed as populations of special concern.
What is happening in the Fraser?
The initial transformation of the Lower Fraser and its surrounding delta from wetlands to farmland occurred by diking off and draining these areas, severely reducing critical salmon habitat. Other development, as well as the elimination of surrounding forests to create a major metropolis, has had a variety of dire consequences for salmon, including warming river temperatures, water pollution from urban runoff, and irregular water flows. Today, flood control mechanisms or “gates,” alter natural hydrological cycles, impact water quality, and create barriers that impede fish passage.
In order to begin reducing these impacts, with the aim to set salmon and Southern Resident orcas on a restorative track, there must be collaborative efforts to conserve remaining salmon habitat and efforts to restore that habitat which has been degraded.
FOR MORE DETAILS AND INFORMATION, VISIT: Toward a vision for salmon habitat in the Lower Fraser River | Raincoast Conservation Foundation
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