300 boats x 10 encounters, puts us at 3,000 a day. 9,000 over 3 days. I believe they say 50% survival rate, that's 4,500 dead chinook according to them, is the way I've always thought they did it.
Adjust the boats to actual boat surveys and encounters to creel reports and test fisheries and their survival rates and that's how you get to the 3,900 real quick.
I don't believe it's 3,900 tagged chinook, but again, could be wrong.