The governor appoints the commissioners, giving him indirect control over WDFW. My guess is that the gov has enough on his plate with taxes and his climate stuff that he tells WDFW to "play nice with the tribes." Meaning he doesn't want tribal issues showing up on his desk. They donate campaign money, after all. So WDFW caves to whatever tribes want.

Otherwise it would make sense on a number of issues to return to the days of the Fisheries Advisory Board (FAB), which was the court-appointed master to adjudicate most state-tribal fishing disputes. The FAB master would rule based on the case law of US v WA.