Thanks Tums, but this has nothing to do with my question's.
I am just curious.
I avoided the answer because it is something that I have discussed / disagreed with people over until I was Blue in the face.
I believe there is no such thing as a set FCR for a species unless you you achieve a static set of parameters. I believe FCR changes during a species life cycle and also due to enviromental influences.
Here is a link to a study by Arkansas Pine Bluff. In it you will notice that just by changing density their FCR dropped from 2.6 to 1.4 for LMB.
APB LMB study