If by US vs State of Washington, you are referring to the suit that resulted in the Boldt decision then this may clarify. That was the suit that ended in a decision that gave the rights to the treaty tribes. After, the legislature through various actions gave the Commission the responsibility to handle the details of how co-management would be conducted. At first it was the Dept of Fish, then they Dept of Fish and dept of wildlife were merged.

I think I got this straight, anyone else with better knowledge can expand.