Juro and French Creek,
The November/December issue of the magazine Fly Fishing and Fly Tying , a UK publication has an article on Atlantic Salmon in the Briticsh Isles. Technical article on why the size and quantity of AS have steadily fallen over the last 40 years. Has not been a 50 lb salmon caught in British Isles since 1969. Now a 30 lb salmon is a rare fish in the British Isles. Prior to that their records show there were 89 caught back to 1860s. Most rapid decline was from 1985 to 1997. To summarize the decrease in commericial netting at sea has not solved the problem. A recent study "The Ocean Life of the Atlantic Salmon" Derek Mills, Fishing News Books indicates that it is the Atlantic Ocean itself which is the probable cause due to the North Atlantic Oscillation Index (NAOI) effect. In simple terms this measures the climate of the North Atlantic and land bordering the atlantic. The North atlantic is dominated by high atmospheric pressure in the the south (Azores High) and low pressure in the North (Icelandic Low). These vary from year to year, and tend to vary in parallel. This results in water temperature changes, colder water reduces the salmon's feeding opportunities, therefore lower size and higher mortaility while at sea. Records allowing the calculation of NAOI go back to 1860. Since the mid 1980s and the NAOI has been very high and runs of salmon very small. Hence the salmon which traditionally go to Arctic and sub arctic waters off of Iceland and Norway are subjected to lower water temperatures and food supply. The other statistics mentioned in the article (reductions of salmon forage, plankton, eels, herring, etc) also correlate with the NAOI possibly being the cause of lower returning salmon and salmon size.
Technical article which I paraphrased from. Don't know how we can warm the North Atlantic for the salmon to feed and survive.
This is a magazine you can probably pick up at your local Borders store. Has some good British Isle fly fishing information on trout, salmon, saltwater which I pick up peridically.