I live less than two miles from the Yakima, and do fly fish it on a regular basis. The number of salmon anglers on the river is negligable to begin with. On opening weekend we drove the entire length of the open section for salmon, and saw very few salmon fisherman, all of them them on the bank.
Although I don't believe that it has any impact on the trout fishery, I think they opened the wrong section of river. With 17,000 salmon in the river, they should have opened the river from Roza dam downstream to about Prosser Dam. This would have allowed for bait, motorized boats, and a reasonable shot at catching some fish. All this while not disturbing the fly fishing section and causing a politcally bad situation. This way everybody comes out ahead.
Best of all, I could have used my new boat!!!