what ratio are they looking for to have an opening?
Ever since the DFO presentation on MSF last Fall I looked pretty hard & did not find that exact information.
This data suggests a rate go 50% or greater:
MASS MARKING AND MARK-SELECTIVE FISHERIESwww.psc.org › download › sfec12-1
Chinook data begins on page 68
The 50% rate was similar to what DFO mentioned last Fall.
MSF's here in WA are VERY complex; the season that just opened was opened with a set threshold of wild fish mortality (probably 20% of all wild fish caught/released (known as "encounters" in current government fish-speak) & the season was closed when the estimated wild Chinook catch reached around 1,000 fish (200 or so mortalities). Some fisheries are opened with a set season usually 1-3 months. The third category is where the wild stocks are so bad off there is just a closure with NO SALMON FISHING ALLOWED. We went from 20 or so MSF's in 2019 - 2020 to just 5 or so for 2020-2021, so default down here is closed. The mark rates as seen from the above data support an opening, but the wild stocks sized do not support an opening.
As for BC, who knows? Down here it all depends on the health of the wild stocks irregardless of mark rates; if BC goes the same route you COULD end-up like us and go from catch-and release to a total closure in the ties/areas the depressed Fraser stocks are.
IMO down here a lot of has to do with the influence of what are Member tribes of the 1855 treaty have over WA state "inside fisheries":
They co-manage the inside fishery as equal partners to WA state, & meetings are secret.
This is the same treaty that had the big court case in 1974 (Boldt decision). They were getting screwed before the treaty, and since the treaty have gone from fishing non-terminal areas to primarily fish terminal areas (nets in rivers). Dunno about the effect of this but they catch fewer fish now than they did before the 1974 Boldt decision. I agree with their rights but strongly disagree with their methods (nets in rivers).