Menu

Ireland's sailing, boating & maritime magazine

Basking Shark Mystery Solved off West Coast

16th September 2022
Basking sharks off Clare coast solved mystery
Basking sharks off Clare coast solved mystery

The West Coast of Ireland is the first place in the world where the annual reproductive behaviour of basking sharks has been seen.

“It is astonishing that this wonder of the natural world has remained hidden for so long,” according to Professor David Sims, Senior Research Fellow at the University of Southampton and lead author of a study carried out by biologists from the Marine Biological Association and the Irish Basking Shark Group.

It has revealed “the global importance of the West Coast of Ireland for the endangered species.”

Circling formations have been documented on a few occasions over the past 40 years in the North-West Atlantic off Canada and the USA. But although basking sharks are often seen filter-feeding plankton in the UK and Irish coastal waters during the summer, the circling formations were rarely seen. Until now, scientists could not explain the behaviour.

Using underwater cameras and aerial drones off County Clare from 2016 to 2021, scientists got video footage of 19 circling groups. Each comprised between 6 and 23 sharks swimming slowly at the surface, with others deeper down.

“This research has shown the importance of Irish waters,” says Dr Simon Berrow of the Atlantic Technological University, Galway and the Irish Basking Shark Group, who co-led the research: “How usually solitary basking sharks find a mate in the ocean’s expanse has been an enduring mystery. Our discovery of these basking shark grounds in our coastal waters makes it more urgent that this species gains protection in Irish waters from potential threats, such as collisions with marine traffic and the impact of offshore renewables.”

Legislation to protect basking sharks in Irish waters was drafted this year, although they are protected in many parts of the world. It remains to be signed into law.

Published in Marine Wildlife
Tom MacSweeney

About The Author

Tom MacSweeney

Email The Author

Tom MacSweeney writes a weekly column for Afloat.ie. He presents the monthly programme Maritime Ireland on Podcast services and Irish radio stations.

We've got a favour to ask

More people are reading Afloat.ie than ever thanks to the power of the internet but we're in stormy seas because advertising revenues across the media are falling fast. Unlike many news sites, we haven’t put up a paywall because we want to keep our marine journalism open.

Afloat.ie is Ireland's only full–time marine journalism team and it takes time, money and hard work to produce our content.

So you can see why we need to ask for your help.

If everyone chipped in, we can enhance our coverage and our future would be more secure. You can help us through a small donation. Thank you.

Direct Donation to Afloat button

Marine Wildlife Around Ireland One of the greatest memories of any day spent boating around the Irish coast is an encounter with marine wildlife.  It's a thrill for young and old to witness seabirds, seals, dolphins and whales right there in their own habitat. As boaters fortunate enough to have experienced it will testify even spotting a distant dorsal fin can be the highlight of any day afloat.  Was that a porpoise? Was it a whale? No matter how brief the glimpse it's a privilege to share the seas with Irish marine wildlife.

Thanks to the location of our beautiful little island, perched in the North Atlantic Ocean there appears to be no shortage of marine life to observe.

From whales to dolphins, seals, sharks and other ocean animals this page documents the most interesting accounts of marine wildlife around our shores. We're keen to receive your observations, your photos, links and youtube clips.

Boaters have a unique perspective and all those who go afloat, from inshore kayaking to offshore yacht racing that what they encounter can be of real value to specialist organisations such as the Irish Whale and Dolphin Group (IWDG) who compile a list of sightings and strandings. The IWDG knowledge base has increased over the past 21 years thanks in part at least to the observations of sailors, anglers, kayakers and boaters.

Thanks to the IWDG work we now know we share the seas with dozens of species who also call Ireland home. Here's the current list: Atlantic white-sided dolphin, beluga whale, blue whale, bottlenose dolphin, common dolphin, Cuvier's beaked whale, false killer whale, fin whale, Gervais' beaked whale, harbour porpoise, humpback whale, killer whale, minke whale, northern bottlenose whale, northern right whale, pilot whale, pygmy sperm whale, Risso's dolphin, sei whale, Sowerby's beaked whale, sperm whale, striped dolphin, True's beaked whale and white-beaked dolphin.

But as impressive as the species list is the IWDG believe there are still gaps in our knowledge. Next time you are out on the ocean waves keep a sharp look out!