So they are getting paid for that work? There is the more salmon to catch angle but the are probably other benefits too. I would venture they have the most to gain from this
Imagine if you were a Yurok person and your people lived for thousands of years, as a unique culture, and where substituting off of salmon was integral to that culture, only to have foreign invaders remove you from your lands, put you on reservations, and effectively destroy the lifeblood of your people by damming the rivers. Now imagine how after several generations this would damage your people as a group economically.
Given that history, it seems strange to question that the Yurok people might have financial "benefits" from this kind of project.