B.C. flooding: ‘Significant’ salmon losses expected
Salmon loss could be significant because of the climate crisis-related disaster this week that caused southern B.C.’s rivers to rush at levels not seen in hundreds of years, say experts.
Pink salmon spawned at the end of September in the Vedder/Chilliwack and the Fraser rivers, making them particularly vulnerable to the high flows, said Marvin Rosenau, the main fisheries instructor in the department of fish, wildlife and recreation at the B.C. Institute of Technology.
Rosenau, who is also a member of the Rivers Institute at BCIT, said the surge in rushing water caused by the atmospheric river that hit southern B.C. Sunday probably caused quite a bit of “scouring” of eggs from the gravel.
Salmon dig holes in the gravel and drop their eggs and then the female uses her tail to beat the gravel to cover the hole. Those eggs incubate and hatch in the spring.
“So you would have to assume there would have to be a significant impact,” he said.
Chum salmon have just finished spawning while coho are in their peak spawning season right now, he added.
So that makes chum also vulnerable to losses — although Rosenau said they like to spawn inside channels that aren’t usually affected by the heavy flows, so they would be a little more protected. Chum, however, are already threatened and had a record low run this year, he added.
The Fraser River between Hope and Mission has one of the largest runs of salmon spawning in the province. Rosenau estimated that about 50 per cent of pink salmon spawn in the main stem of the Fraser River.
The large flows in the Fraser River usually happen in the spring when the snow melts, but the atmospheric river caused an extraordinary one-in-500-year event with flows of 6,300 cubic metres per second, he said.