Jacob,

I think the issue is they do the redd counts and make a prediction of returns based on a certain percentage.

Then when the season comes around they guestimate the return they are getting on the hatchery fish and then re-guestimate the return for the natvies based on that.

So if the hatchery fish are returning at a rate less than initially predicted they assume the native fish will also. Thus the mid-season closure.

A bummer certainly, however I feel its better to be safe than sorry.