I thought I would start a new thread and one with data not speculation. Below is the ADF&G update on the Kenai River production models using the data from this year return. As you can read for yourself the Brood Year Interaction model is still the best fit and the Markov table has held firm. So the conjecture on needing a new model has not been supported. For escapements in the 600,000 to 900,000 range the mean yield is around 4 million while at greater than 1.3 million it is 2.8 million. The Markov table is what has happened in the past and is not a model per se. It is empirical data.
Also the new projection on inriver escapement at the sonar counter this year will be around 1.7 million.
Next year could change things again on model fit depending on how the return comes in.
With the large Kenai return this year folks have been talking about whether the brood interaction model is history or if the EG is going to change. Assuming the final 2011 Kenai run is 5.7 million, I updated the brood table and estimated the fit of the various models we included in our 2010 EG report. The following is a brief comparison:
2010 report Updated Model
Ricker Model – R2 0.528 0.547
BYI Model – R2 0.600 0.593
I also updated the Markov table and the BYI simulation model (see below).
So, this analysis indicated a small increase in the fit of the Ricker model and a small decrease in the fit of the BYI model, but the BYI model is still the best fit model. In the Markov table, the mean yield for escapements >1,300,000 increased from 2,566,000 to 2,863,000, but the highest mean yields were still in the 600,000 – 900,000 range. The BYI simulation with the updated model parameters indicated the goal range would change to 700,000 to 1,300,000. If our smolt data is accurate, we may have another large return of 2.3’s next year coming off the 2006 brood year.