Heat wave adds to salmon’s migratory obstacles

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The Early Stuarts, first of this season’s sockeye, are now ghosting in from the North Pacific, homing on the freshwater plume of the Fraser River.

It spills in a vast, silty lens across the Salish Sea, one of the last mysterious signals guiding them toward the final dangerous stretch of a 16,000-kilometre journey.

They will mass in the river mouth, then, a couple of weeks from now, turn into a current discharging just south of Hell’s Gate Canyon at a volume equivalent to one-and-a-half Olympic-sized swimming pools every second.

Mottled backs still a deep, glossy green, sides silver bright, soon to become deep crimson, this is the first of 19 sockeye runs to muster for the Fraser migration. The Early Stuarts have the longest distance to travel.

How many will return is the subject of arcane forecast statistics but federal fisheries scientists estimate a 50 per cent probability of only 30,000 Early Stuarts this year, less than 20 per cent of the average return of 162,000 on this spawning cycle.

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