VAGRANT SPECIES DIARY
Swordfish, Isle of Man
THE SIGHTING, IN AUGUST, OF A FULLY grown, breaching 3m swordfish from a boat 8km off the Isle of Man must have represented a truly jawdropping moment for the lucky Manx Whale and Dolphin Watch crew. And its subsequent close approach to the survey vessel will only have added to the unforgettable experience. The size of this fish, combined with its distinctive weaponry, lends it an instant wow-factor, and with fewer than 10 recorded sightings in UK waters, it is an unexpected treat.
Swordfish, together with the similarlooking marlin, comprise a group of a dozen or so large predatory fish species known as billfish. Marlin are popular quarry for ‘sport’ anglers and a family that includes the fastest fish in the world, the sailfish. The swordfish, though, is both the most widely distributed globally and the species with the widest water temperature tolerance.
They often feed at depth on fish, squid and crustaceans, can grow (rarely) to 4.5m and are highly migratory, occurring in the Atlantic, Pacific and Indian Oceans, as well as the Mediterranean Sea.
It is one of a number of pelagic fish species being noted more regularly in our warming waters. In recent years, sightings have included individuals being washed up (sometimes still alive) on the west coast.
A swordfish was also identified from aerial photos as part of a wind-farm survey off the coast of Aberdeenshire in 2020. It, or another individual, spent some time in the Firth of Forth a year or so later, where its dorsal and tail fin could be regularly seen from Portobello Beach, Edinburgh, as it cruised just below the surface.