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Do you dream of seeing sharks up close? For that, you don’t need to travel to the other side of the world. Each year, an astonishing spectacle unfolds off the coast of Ireland. In a few bays, one of the planet’s largest fish ventures so close to shore that it can be observed from a boat or from the cliffs, offering a rare—and safe—experience for nature lovers.

Why Ireland has become a refuge for basking sharks

With a length of up to 10 meters, the basking shark is the second-largest fish in the world, behind the whale shark. And, despite its impressive appearance, it poses no danger to humans. Like the whale shark and the big-mouthed shark, it feeds solely on plankton and tiny copepods that it filters by swimming with its mouth open at the surface.

Between April and early July, then again in August and September, hundreds of basking sharks move to the west and southwest coasts of Ireland. The plankton blooms there are particularly abundant, favored by the shallow continental shelf. This concentration of food draws the animals into bays near the beaches, a phenomenon unprecedented on a global scale.

For biologist Chelsea Gray, a researcher with the Irish Basking Shark Group (IBSG), this proximity is what makes the country’s situation so unique. “Basking sharks are global citizens”, she told the BBC, adding that “Ireland is really unique, because they come so close to the shore”. A feature that allows them to be spotted both from the cliffs and during sea excursions.

Cette situation contraste fortement avec leur histoire. Dans les années 1950 et 1960, Achill Island – la plus grande île du pays, située à l’ouest – était le principal centre mondial de pêche et de transformation du requin pèlerin. Son immense foie, pouvant peser jusqu’à une tonne, était exploité pour produire de l’huile utilisée dans les cosmétiques, les lubrifiants industriels ou encore certains traitements médicaux. Ses nageoires étaient également recherchées pour la soupe d’ailerons de requin. La surpêche pratiquée en Irlande, mais aussi en Norvège, au Japon ou au Canada, a conduit l’espèce au bord de l’effondrement à la fin du XXe siècle.

A highly supervised encounter to protect an endangered species

Globally, the species remains threatened and has been listed on the International Union for Conservation of Nature (IUCN) Red List since 2018. But since the last basking shark caught in Ireland in 1984, the situation has gradually improved in Irish waters. Protection was further strengthened in 2022, when the basking shark was included in Irish wildlife legislation. It is now illegal to hunt, injure, or disturb its feeding and breeding areas.

Scientists now aim to turn the recommendations given to tour operators into a real legal framework. Concretely, boats should not speed toward the animals. When a shark is spotted within 50 meters, the engines must be put in neutral to let it decide how close it wishes to approach.

“Our priority is not to interfere too much with the animals. We typically stay well back and let them come to us. If we can intercept their path at a safe distance, they sometimes take a look and then move away”, explains Paddy Byrne, owner and captain of Sliabh Liag Boat Trips, to the BBC. He also notes that “they are wild animals, and we are privileged to see them”.

Exceptional Encounters

Observations are never guaranteed. Yet, outings regularly offer glimpses of seals, dolphins, seabirds, and sometimes small whales. But when basking sharks appear, the memory tends to be unforgettable. “We saw a baby basking shark even before leaving the first bay,” recounts Izzy Sharpe to the BBC, before adding: “On the way back, suddenly hundreds of basking sharks appeared. Wherever you looked, they were surfacing. It was incredibly special”.

Hazel Keegan, a regular on Achill Island, also recalls an extraordinary encounter. “They ended up swimming all around the boat. We could clearly see the white of the inside of their mouths. They kept passing under the boat! It was only then that I truly realized how long they are,” she tells the British media. Even when luck isn’t in your favor at sea, surprises can come from the shore. Laura Brown recalls finishing her stay without spotting a single shark during her excursion.

“On the last day, the weather was perfect and we decided to head back to Keem Bay one final time. We looked into the bay and there were about six to eight basking sharks! My son, his friend, and I ran to grab the paddleboard. They swam beneath us and around us. It was truly magical”, she tells the BBC. A reason to consider Ireland a top destination for those dreaming of observing one of the planet’s largest fish in its natural habitat.