The waters surrounding Ireland host a surprisingly diverse population of sharks, a fact often overshadowed by the island’s terrestrial wildlife. Positioned on the edge of the European continental shelf, Ireland’s marine environment offers a rich blend of productive coastal waters and deep Atlantic trenches. This variety in habitat supports numerous shark species, from the world’s second-largest fish to smaller, elusive deep-sea dwellers. Over 70 species of sharks and rays, known collectively as elasmobranchs, have been documented in Irish waters, establishing the region as a significant marine biodiversity hotspot.
The Regularly Encountered Species
Three species are the most commonly sighted visitors to Ireland’s coastal and inshore waters. The Basking Shark, the second-largest fish globally, is a gentle filter feeder that can reach lengths of up to 12 meters. These colossal animals are typically spotted near the surface between April and August, when they arrive to feed on dense blooms of plankton.
The Blue Shark is a highly migratory species that frequently visits Irish waters during the warmer summer months, usually from June to October. These graceful, slender sharks have a distinctive luminous blue coloration and can grow to over three meters long, primarily preying on fish and squid in the open ocean. Tagging programs have tracked individuals from Ireland across the Atlantic, highlighting their vast migratory routes.
The Porbeagle Shark is another regular presence, recognized by its stocky build and a white patch on the rear of its dorsal fin. As a member of the same family as the Great White, the Porbeagle is a fast, warm-blooded predator found in Irish waters year-round. This species is classified as critically endangered in the Northeast Atlantic due to its slow growth rate and low reproductive capacity.
Deepwater and Transient Visitors
Beyond the coastal species, Ireland’s deep offshore trenches and dynamic ocean currents introduce a range of deepwater and transient shark species. The Tope shark, a slender hound shark that can reach two meters, frequents the continental shelf and coastal areas, with females coming into shallower waters in summer to give birth. Tagging data confirms that these long-lived sharks travel immense distances, with some individuals tagged in Ireland found as far away as the Canary Islands.
Critically endangered species like the Angelshark, a flat-bodied shark often mistaken for a ray, were once common along the coastline but are now confined to only a few remaining strongholds, such as Tralee Bay. The deep-sea environment hosts species like the Greenland Shark, one of the longest-living vertebrates on Earth, and the Blackmouth Catshark. Scientists discovered a vast nursery of thousands of young Blackmouth Catsharks in the deep Atlantic waters off Ireland’s west coast, revealing previously unknown breeding grounds.
The possibility of a Great White Shark presence remains a topic of public discussion, but there is no confirmed resident population. While warming sea temperatures increase the likelihood of transient, predatory species passing through Irish waters, any such occurrence would be extremely rare and not indicative of a resident species.
Assessing the Risk to Humans
Concerns about human safety often drive public interest in sharks, and the data for Irish waters is highly reassuring. There are zero confirmed records of unprovoked shark attacks on humans in Ireland. The few documented shark-related incidents have been provoked, such as the 2018 event where a fisherman sustained an injury after handling a Blue Shark that had already been hooked.
The most visible species, the Basking Shark, is a plankton feeder and poses no threat to humans, despite its enormous size. Most of the other species are either small, like the various dogfish, or inhabit deep offshore waters far from recreational areas. The risk to a swimmer or surfer in Irish waters is statistically negligible.
Following basic marine safety guidelines reduces the chance of any negative interaction with wildlife. Swimmers and watercraft users are advised to maintain a minimum distance of four meters from Basking Sharks to avoid disturbance, particularly as they feed near the surface. If a shark approaches a swimmer, the proper response is to remain still and allow the animal to pass naturally.
Monitoring and Protecting Irish Sharks
The health of the Irish shark population is an important indicator of the wider marine ecosystem, and monitoring efforts have increased significantly in recent years. The Basking Shark was granted legal protection under Ireland’s Wildlife Act in 2022, making it an offense to intentionally hunt, injure, or interfere with the species. This measure is designed to safeguard the large numbers of sharks that aggregate in Irish coastal waters, believed to be a globally significant gathering site.
Conservation groups, such as the Irish Basking Shark Group, advocate for science-informed protection and encourage public participation. Citizen science programs, like the Basking Shark Sightings Scheme, allow the public to report observations, contributing valuable data on the species’ distribution and behavior. The Marine Sportfish Tagging Programme works with recreational anglers to tag and release sharks, including Porbeagles and Blue Sharks. These efforts provide scientists with long-term data on migration and population health, essential for developing effective strategies to protect species like the Porbeagle and Angelshark.