I agree with Whitebuck that the native fishery has been out of control for the last 20 years. Political decisions during that time from Ottawa have cut budgets,tied the hands of enforcement in the field, and muzzled the scientists that know whats going on.
Regarding the better performance of the lower river stocks,they do not have to navigate the migration route up the Fraser canyon against strong current and the record high temperatures we have had the last few years. If the upriver stocks are weakened by a virus that affects their heart and liver,some of them don't get to the spawning grounds or if they do, they die unspawned. The Chilliwack sockeye run, which has been performing better, is unique in that the smolts migrate out through Jaun de Fuca not Johnstone Straits and don't run the gauntlet of fish farms. I wonder if there is any connection..... I think there are a number of factors at play and they are all negative and all human caused in one way or another. What a trail of destruction we leave behind us.....