Ok, but this is important:
"Due to restrictions in place in response to the COVID-19 pandemic in early 2020, the out-migration of Pink salmon fry from the brood year (2019) was not assessed. As the brood year fry abundance is typically used to forecast returning adult abundance, different methodology was required to forecast returns for 2021. In the absence of juvenile data, an escapement time-series (1957-2019) was used for forecasting, however this escapement data has been inconsistently assessed, and as such the forecast should be treated with exceptional caution."
It sounds to me like this forecast is nothing more than a very conservative guess designed to discourage fisheries that will impact extremely depressed sockeye stocks. Unless there were major gravel-moving events that impacted the brood year, I don't see why it would come in below the 90% estimate.
Does anyone know what they mean by an "escapement time-series"?