Hi MicroMan, can you please reference that?
Albert Bartlett, physics professor emeritus at Univ. of Colorado in Boulder, is the main person who's publicized this. You can see it in his Physics Today article from July 2004. It's online at:

http://www.gatsby.ucl.ac.uk/~pel/environment/population_pt04.html

The Bartlett reference is for the per capita oil production peak, not the fish and grain peaks.
Thanks for the interesting link. The FAO stats for total world fishing production appear not to show a peak: for 2003, the last year in their series, they have production at over 135 million metric tons, the highest ever.
Not a peak in per capita fish production, either.