I just did a search on this and it is happening everywhere, even in China. There's is caused by arsnic used in gold mining and they are dumping it in their streams. But other reasons given were temp change in waters, diseases. You know can't help but to wonder-remember Mad Cow-kill the cows off so you have to go to another food source. Could it be the same ole game? Some of the states mentioned were Ohio, Pa, Mich, Tex and Va. Just search large fish kills, you will be shocked.