Frank Reid wrote:
You are addressing fly fishermen who fish primarily for a COLD
WATER FISH (not carp, not bass, not crappie), trout. A fish that thrives in
34-40 degree water. A fish that would be unaffected by the COLD WATER
BECAUSE THATS WHAT THEY LIVE IN!!

http://www.nrdc.org/globalWarming/ntrout.asp

"It's simple: cold-water fish such as trout and salmon thrive in
streams with temperatures of 50 to 65 degrees Fahrenheit."