Dams indeed are not the only factor. But they m ake a big impact. When the corps put in the lower columbia dams they knew they would kill fish and told the locals about it. The corps own documentation indicated they expected the Snake river fish to expire shortly after the dams were built. That's why there were so many hatcheries built below, it's mitigation. Turbines are a part of the problem, but indeed temperatures have a huge impact (next to barging fish, increased nitrogen, increased sediment in the water column and predators), in fact there is an algae boom occuring on the Snake right now in some places, who the hell ever heard of an alage bloom (large one anyway, maybe it's normal but seems odd to me) on a river? It not a river now, it's a mud puddle.