Is there a 12" size limit on bass in twin lakes?
It depends on which Twin Lakes you are referring. If this is the Twin Lakes in North Idaho, there is no minimum length limit on bass. If this is the Twin Lakes in the Southeast Region of Idaho, then the minimum length on harvestable bass is 12".
As a "rule-of-thumb" waters north of the Salmon River have no minimum length limit on bass. Waters south of the Salmon River have a 12" minimum harvest limit.