Fraser sockeye forecast halved as river temperatures climb
The in-season estimate has been revised twice since June. Test fisheries at Mission are reporting the warmest August water in the record.
The in-season forecast for the Fraser sockeye run was cut nearly in half Friday, the second downward revision since June, and the reason is not a mystery anyone is bothering to preserve: the river is too warm.
The test fishery at Mission recorded water above nineteen degrees for eleven consecutive days in early August — the warmest stretch in the station's record. Past eighteen degrees, migrating sockeye begin burning energy faster than they can spare it; past twenty, pre-spawn mortality climbs steeply enough that managers start subtracting fish from the forecast before anyone catches them.
The panel's response so far has been the standard sequence: reduced openings, then no openings, then the harder conversation about whether the late-summer runs should be fished at all in warm years. Two of the four management groups are now below the threshold where any commercial opening is contemplated.
The longer arc is the uncomfortable part. The river's August temperature has crossed the stress threshold in seven of the past ten years; the forecast model that once treated warm water as an anomaly now carries it as an assumption. As one biologist on the panel put it: "We used to model the run and adjust for temperature. We now model the temperature and adjust for run."
