Sorry Hamish, I have to disagree on one point. Salmon decline is not to do with Hydro power or dams or whatever. Salmon decline is to do with the fact that commercial fishermen have, over the last fifty or so years, discovered the migratory habits of that fish and have exploited that knowledge. Check out the commercial fishings of the coast of Iceland and the Northumbrian drift netters, who know the fish runs and use small guage monofil nets that are two to three miles long, then come back and make your statement. Modern Hydro schemes take account of, and make provision for, fish movements. This is one subject that I am very passionate about.