Thousands of By-The-Wind Sailors, rare colonial hydrozoans related to the Portuguese Man 'O' War, have washed up along the Sefton Coast after strong westerly winds pushed them into the Irish Sea. The tiny creatures, which are barely a few centimetres long, have been found from Anglesey to St Bees Head, with many still visible on the tideline at Ainsdale.
Rare visitors arrive in numbers
By-The-Wind Sailors, scientifically known as Velella velella, are not jellyfish in the conventional sense. They are colonies of predatory polyps that form a little platform with a thin membrane on top that acts as a sail, blowing them across the world's oceans. Their colours fade quickly once washed up, and their desiccated remains soon blow away or blend into the strandline.
According to John Dempsey of Green Sefton, the Sefton Council service that manages the coastline, the last time such large numbers were seen along this coastline was in November 2021, during a large wreck in early winter storms. He noted that even last week, a short walk along the tideline at Ainsdale revealed good numbers of the dried-up husks of these fascinating organisms.
Global journey ends on Sefton shores
Dempsey, who writes a column on the flora, fauna and history of the coastline, said the strong westerlies of a fortnight ago pushed thousands of these colonial organisms into the Irish Sea. He expressed wonder at their origin, asking what Caribbean bay, Pacific reef or Atlantic strait they had drifted from, and where their epic journey started, only for it to end on the Sefton Coast.
By-The-Wind Sailors have a worldwide distribution, drifting on the surface of all the oceans, their destinations decided purely and randomly by wind direction. While they don't pack the sting of usual jellyfish, the advice is to adopt a "look but don't touch" approach when they are fresh and colourful.
Advice for beachgoers and pet owners
Dempsey also warned that dogs that "eat first and ask questions later" could become sick if they consume these little critters, so keeping dogs under control and ideally on a lead along the tideline and especially at the water's edge remains pertinent.
Green Sefton brings together the Coast & Countryside, Parks & Greenspaces and Grounds Maintenance teams for a joined-up approach to the vital management, development and oversight of Sefton's beautiful coastline, parks and green spaces.
