Unfortunately for these benign elasmos (sharks and rays) they lack big teeth, giant poison filled tail barbs, and a mean disposition.
The future for them is looking pretty grim as long as fishermen have no problems jumping into waters filled with Entamoeba histolytica:
Ian Welch and four colleagues spent 45 minutes battling the 6ft wide and 14ft long fish, which was too big to weigh but was estimated to be about 23 stones.
"When we got it to the surface I could not comprehend that something that size existed," said Mr Welch, 45, a doctor in freshwater biology, from Aldershot, Hants. "It was as big as a snooker table."