Size does matter

Just had sardines on toast for lunch - lovely. But did you know that there's no recognised definition of a sardine?  It's just a small member of the herring family, and what makes it a sardine, is its size.  Here in the UK, if it's less than around 6" it's classed as a sardine, and if it's longer than that, it's a pilchard.  So if it stays in the ocean, it will eventually grow from a sardine into a pilchard - same fish, and also nice on toast.