Today is the 40th anniversary of the release of Jaws, the movie. Rarely can a film have entered into the collective psyche in the way that this one did. I can’t remember when I first saw it although I do remember when I first didn’t. It was shown on television here when I was a very small child of four or five. I came home from school the following day highly indignant because my teacher had asked the class who had stayed up to watch it. Apparently – or so I interpreted it – mine was one of the very few hands not to be raised. Of course I made up for it in years to come, watching the films (all of them) and reading the book. Perhaps that’s why the spectre of sharks has never been far from my mind when swimming in seas and oceans as geographically, biologically and climatically diverse as the Irish sea, the Mediterranean and the Indian ocean. Older people tell me it didn’t used to be that way. ‘Sharks?’ I recall a great-uncle saying. ‘No, you might worry about sharks if you were torpedoed [he was in the Merchant Navy in WWII] but not at the beach. Never at the beach.’ I did though – and a cousin and I used to spend goodly portions of our Easter holidays in that well-known shark mecca, the Lleyn Peninsula, committing to heart the tragedy on every page of a luridly-illustrated book entitled something like “Shark Attack!” that we’d picked up for 50 pence in the discount bookshop in Portmadoc. Needless to say, any large marine creatures in Cardigan Bay remained prudently elusive.

My children still haven’t seen any of the Jaws films (yes, my five year-old self would be disgusted with me) but the idea of sharks as Something Bad and Dangerous is sewn into their consciousness. I realised as much three or so years ago at a tearoom in Orkney’s Bay of Birsay. ‘There was a pod of orcas out there last month,’ the waitress said, as she put her tray down. My four-year son and niece squabbling over turns of the binoculars in front of the picture windows either did not hear her or, more probably, orca meant nothing to them. My two-year old daughter, however, with eyes fixed firmly on the cakes, tried out the new word. ‘Orca?’ she said.

The waitress smiled, wiped her hands on her apron, and went over to a small display of postcards next to the homemade jams. She put one glossy card on the table. ‘Here,’ she said, pointing to the impossibly smooth curve of black and white back. ‘This is an orca. It’s also called a killer whale although, really, it’s a dolphin’. With wide, interested eyes, my daughter looked up and nodded as if she understood. Then she frowned and looked down again. She jabbed her finger against three tall triangular fins that broke the surface of the water around the orca’s back. ‘Sharks,’ she said, unhappily. ‘There are no sharks in the swimming pool.’ We adults nodded in hearty agreement. ‘Sometimes in the sea,’ I began, before sensing the need for a change of tack. ‘But these aren’t sharks. They’re orcas. And you needn’t worry; this sea is far too cold for swimming.’

The storm that had sent us hurrying along the coast away from Skara Brae had subsided. Wind-driven sea-spray still misted the tearoom’s windows but the seaweed on the shore outside no longer tossed its rubbery green tentacles from side to side like long-haired headbangers at a heavy metal concert. The water – so recently a foaming cauldron with sea birds expertly piloting the wind above it – was grey and almost glassy, and the birds now rode its surface, easy as paper ships on a boating pond. A slice of sun poked out coyly from behind a cloud to coax diamond chips of light from the sea. The children at the window were sufficiently entranced not to notice the plate of cakes on the table behind them. Still clad in now slightly steaming waterproofs, they’d reached some sort of accord as to who had which pair of binoculars. No matter that one was looking through the wrong end; they were happy and quiet. We ate our cakes and drank our tea. I wondered how many times I would need to return before I saw an orca. The four year-olds shrieked simultaneously. Several small balls were bobbing closer to shore before resolving themselves into large grey animals that humped fatly out of the water and onto a narrow spit of sand. One rolled onto its side and waved a celebratory flipper at the sun. I stared at the seals, thinking them fair compensation for the lack of orcas. My daughter looked at them before shaking her head a little sadly. ‘Sharks,’ she said.