Pre-season estimation is not a concrete number and is constantly revised as the season approaches. The estimation is not a fixed number, but instead many numbers are given at different probability level. Usually, the higher the probability, the lower the number is. The estimation is usually given to the public at 50% probability, but often people will end up finding other numbers (at 90%, 75%, 10%, etc) from different sources. This is usually how rumours are started among anglers. The pre-season estimation is usually not close to the actually stock return. This does not mean mismanagement, but simply because biologists still have many unknowns in the Pacific Ocean where pink salmon are during their adult phase.
Pre-season estimation for pink salmon is determined from fry outmigration estimate.
The average fry outmigration number since the 1960s is 370 million fish, which has yielded an average of 12 million adult returns.
The fry outmigration estimate for the 2007 run was 615 million fish, almost double of the long term average, therefore the pre-season estimate of that year's run was 20.3 million fish. Despite of the downgraded return number when the season was over, it still yielded 500 million outmigrating fry for 2009's stock. If all goes well in the Pacific Ocean, we will see a good pink salmon fishing season.
Pink salmon season typically starts in a few weeks from now on Vancouver Island. Late July and August are when we begin seeing fish in Howe Sound, the Squamish River system (look for possible fishing or retention closures/openings), Capilano River mouth, Seymour River, Deep Cove and Cates Park. The Fraser River pink salmon run usually starts in early to mid August, but the number of fish in the early part of the season is low, so they are too spread out to be targeted in the Tidal Fraser River. They could however be caught in the non-tidal portion, upstream from Mission. The peak of the Fraser River pink salmon run usually happens in the first two weeks of September, but they could be caught by the third week of August too.