“This is St. Peter’s fish, the fish Jesus fed the multitudes,” he says, his raspy voice resonating like a preacher’s. Unlike Jesus, however, Martin does not give his fish away. Each day he sells ...

When you eat salmon or carp or tilapia, you might imagine that the fish had once been swimming free in the wild. In recent years, however, more and more of the world’s seafood have grown up on a farm.

He sits at a red and white checkered table, drinking Michelob Ultra in a frosted stemmed glass with a cigar in his right hand, chewing it slowly. The 87-year-old retired doctor from Hutchinson, Kansas ...