This article was originally published in the London Book Fair Show Daily, 16 April 2015.
"We deal with a highly differentiated product. There are hundreds of varieties, and within each variety, there are large ones, small ones, ones just in, and ones that have been around longer than they ought. And consumers wish to examine them before purchase." We might well be talking about books, but actually this is an extract from an academic paper about the New York wholesale fish market–slightly paraphrased to avoid obviously piscine terminology. Fish markets are of interest to economists because they demonstrate some counter-intuitive behaviour: there is sustained price differentiation (different prices offered to different customers for the same thing) and very low elasticity of demand (perfect elasticity would be an exact inverse relationship between price and number of sales; fish merchants do not experience such a direct relationship).