As far as my understanding of the bold decision goes, I think it is 50% of the HarvestABLE numbers, not the actual harvest. Harvestable numbers (at least for shellfish, as that is where my boldt decision knowledge originates) are determined as 1/3 of the total population, leaving the native american catch as 1/6 of the returning population, independant of what commercial and sport catches are. I may be wrong, it has been a while since i read it, but that is my understanding of it.
Matt Korb