Salmon Fishing

My first job out of graduate school was at a rural hospital in Ilwaco, Washington, in a town that is one of the largest salmon fishing ports. Most tourists came to do Chinook salmon fishing on the Columbia or out at sea. During the time I worked there, the fishing industry was depressed, due to restrictions of fishing, controversy over Native American fishing rights and an overall poor economy in the vicinity. The oyster and mussel industries did continue to thrive, however.
The other hospital, in the north end of Pacific County, had previously been a shrimping port. That industry was also dead (though it has obviously started up again as a guy at a farmer's market here sells canned shrimp from South Bend, Washington). The other industry in town was logging, which was facing economic problems and there were many unemployed loggers.
I read today that the salmon runs on the Columbia River have dramatically decreased, for unknown reasons, and fishing has been called to a halt. I am a huge fan of the river salmon and find their annual pilgrimage upriver to lay eggs fascinating. Salmon is also one of my very favorite fish ---- this leads me to wonder about what we have done to the planet. Is it a long-distance impact of the tsunamis? What about the whales and dolphins beaching themselves for no apparent reasons (probably underwater sonar testing)? I don't quite know what to think, but I am definitely thinking about it.