Each summer, when real news can be something of a rarity, our press may carry what are disparagingly known as ‘silly-season stories’ – trivialities professing to be important or fictions dressed up as facts. Infestations of ‘man-eating’ sharks are one such tale. So, too, plagues of jellyfish tormenting sea-bathing tourists. In the latter, at least, there is a germ of truth. The harmless Moon Jellyfish is the commonest jellyfish in our inshore waters.