Euan Ferguson travels to Pembrokeshire, where sightings of sea turtles have surged, to find reasons for the marine invasion This is, it hardly needs saying, the story everyone’s been talking about all week. The turtles are coming! Giant leatherback sea turtles. Dermochelys coriacea , to be formal about it. Those who know about these things include them in an elite group known as “charismatic mega-fauna” – lions, elephants etc – not because they (necessarily) light up a room when they join a party, but because, without wishing to anthropomorphise too much, they’re much “nicer” than slugs and jellyfish, and possess a serious wooo! factor. Children are happy to stare and stare; adults get a frisson at the sheer size, the grace in the water. They are big, up to three metres long. This is one big turtle. This is Turtlezilla. And sightings, normally, are extremely rare. This summer is different though. The Marine Conservation Society (MCS) has asked the public to log any sighting of a giant leatherback. There have already been an unusually high number; eight in the last fortnight, mainly from around here, by walkers, yachtsmen, surfers. August is the month to watch for them. “What we do know,” according to Peter Richardson of the MCS, “is that something’s been happening in the Atlantic which is good for the leatherbacks.” They’re still on the list of critically endangered species – a colony in Gabon which was huge in the 1970s is now practically extinct. But, in the Atlantic, the leatherback population appears to be starting to thrive. So here I am in very wet, very Welsh, very west Wales, near the whales. Looking for a turtle, somewhere out at sea, off the coastline near Solva, a coast of such grandeur it would be rejected by film-location scouts as ridiculously overblown unless they were scouting for ridiculously overblown things such as Dr Who or Camelot . My turtle sighting is, frankly, unlikely to happen. There’s a lot of coast to cover for one: there’s 180