I got the impression that that was going on from the video, I think it was there but perhaps you missed it. I for one didn't even know that the salton sea existed until someone facebooked this video, and before reading your post and without any research concluded that that must be the case (aside from the hispanic part).
I do like the idea in the revival project of capturing the nutrients in the agricultural runoff. I also suspect that the fish die off could be harvested easily (but unpleasantly) to make agricultural products like
compost.