Looks like that will be the next problem, if the Purdey/Brown hypothesis
concerning Mad Cow Disease is accurate, and the evidence seems to support it
much more than any other hypothesis.  If I had a choice, I'd eat organic
beef rather than farm raised salmon, but I'd boil the beef - cooking it
while exposed to air is a very bad idea, leading to oxidized cholesterol,
etc.

"Farm-raised salmon higher in contaminants than wild salmon, study finds
Eric Pianin, Washington Post

Published January 9, 2004 SALM09
Farm-raised salmon, a growing staple of U.S. diets, contains significantly
higher concentrations of PCBs, dioxin and other cancer-causing contaminants
than salmon caught in the wild and should be eaten infrequently, according
to a study of commercial fish sold in North America, South America and
Europe.
The study, using Environmental Protection Agency health guidelines,
concluded that while consumers could safely eat four to eight meals of wild
salmon a month, consumption of more than one 8-ounce portion of farmed
salmon a month in most cases poses an "unacceptable cancer risk." People in
Washington, D.C., New York, Los Angeles, Chicago and Seattle should not eat
farmed salmon more than once or twice a month, the study advises.
The two-year study was paid for by the Pew Charitable Trust and published
Thursday in the journal Science.
Officials of the Food and Drug Administration and the fishing industry took
issue with the findings. They said the contaminant levels in salmon have
declined by 90 percent since the 1970s and the remaining "trace levels" do
not warrant consumers denying themselves the high protein and cardiovascular
benefits of eating salmon.
"We've looked at the levels found . . . and they do not represent a health
concern," said Terry Troxell, director of the FDA's Office of Plant and
Dairy Food and Beverages. "In the end our advice is not to alter consumption
of farmed or wild salmon."
The salmon farming industry points out that all the pollutant levels are
well within the FDA's legal limits and says other foods eaten more often,
such as beef, are bigger sources of exposure.
On average, farmed salmon has concentrations of health-threatening
contaminants 10 times greater than those found in wild salmon, according to
the study.
Farmed fish contain higher concentrations of contaminants than wild fish
largely because they are fed a meal that consists of ground-up fish tainted
with the contaminants, while wild salmon feed on smaller fish and tiny
aquatic organisms.
Removing the skin and grilling salmon removes a significant amount of stored
PCBs, dioxins and other pollutants, the FDA noted.
The Associated Press contributed to this report.
http://www.startribune.com/stories/484/4309047.html"