That is pretty much an impossible question to answer as the only assessment done is a dead pitch count on spawners in the Cheakamus and other tributary streams. There are also no projection on returns as the spawner escapement data is very poor so there is nothing to base the expected return on. The best you can hope for is to look at trend data over a bunch of years and see if things are trending up or down. As you well know, this is a large glacial system with mainstem spawning but no way of determining how many fish spawn and where. The last really intense adult enumeration work was done in the early 90's and it cost lots of money that is now not available. There was a Didson generated count one year on the Cheakamus ( can't remember when, early 2000's?) that put the Cheakamus population at around 500 adults. The Native catch has been monitored over last many years and the catch is always consistently low. The Ashlu stream counts have been seriously downturning now for many years
The Cheakamus has as part of the BC Hydro Water Management plan a juvenile monitoring program that has tracked juvenile chinook population for a number of years now. Generally speaking, the fry numbers they have observed have stayed within the same range over the trapping years. Some years, depending on floods over the fall / winter the numbers go up or down but not exponentially. Ironically the juvenile numbers have gone up since the CN Rail spill of Caustic Soda in 2005. That spill removed most of the predators ( sculpins) that have still not fully recovered so there are more chinook fry surviving to make the seward migration. That has helped to improve the Cheakamus escapement the last few years but it is hardly steller. Would not want to even wager a guess on how few chinook there are on the Squamish system but it is not many.