Not long ago, my encounters with basking sharks were pretty close up. When a scientist researching them off the Isle of Man needed help, with my experience of driving inflatable ribs, I was tasked with steering his small boat up to a 10-tonne shark, closely and carefully enough for him to jab a small tracking device into its dorsal\u00a0fin.<\/p>\n
It was hair-raising work \u2013 they are solid muscle, capable of smashing our hull. Nevertheless, I guided the boat gently alongside, and the device was placed. Like many others before it, the shark swam off unconcerned.<\/p>\n
Now I observe them from further away: either I respond to alerts on social media or visit likely headlands \u2013 a good number of recorded sightings are from people\u00a0on land.<\/p>\n
Basking sharks have an interesting recent history here. They migrate north through island waters from May to August and may\u00a0even breed here, then are rarely seen in autumn. Their migration routes are astonishing<\/a>, with tagged sharks recorded off Morocco to the south and Newfoundland to the west.<\/p>\n But the research was stopped in 2022 as numbers dropped from 885 sightings in 2009 to just a single individual. Lack of food, warmer seas or more likely underwater electricity cables were blamed. It was suggested that electromagnetic fields emitted by the cables repulsed migrating sharks.<\/p>\n A basking shark\u2019s dorsal fin breaks the water\u2019s surface. Photograph: Murdo MacLeod\/The Guardian<\/p>\n