Happy Shark Week everyone! Thankfully, year after year Shark Week is becoming more of a global celebration of the importance of sharks in a biodiversity context than the old-fashioned Jaws-style shark scaremongering. 

Sharks, skates and rays (collectively known as Elasmobranchs) are found all along the Irish coast. Many people don’t realise, but there are actually 72 different species of elasmobranchs documented in our waters, primarily due to the wide range of marine habitats along our coasts and our island’s position on the continental shelf. Our productive waters offer these animals great feeding opportunities, so many highly migratory species will pass through during the summer months but we also have many species which call Irish waters home all year round! 

Our report, Revitalising Our Seas, identifies areas of interest for marine protected area designation in Irish waters. Vulnerable and endangered shark species make up some of the qualifying features to merit the need for these new protections.

Basking Shark – An Liamhán Gréine – Cetorhinus maximus Key Facts:

  • Up to 75 individual basking sharks have been seen together in a single sighting.
  • Basking sharks can reach up to 12 metres in length.
  • A fully grown adult basking shark can weigh 6 tonnes (around the same weight as a large African elephant, an average 4.5 metre delivery truck or two mature Orcas).
  • Don’t be alarmed at their awesome size, these fish truly are gentle giants. The basking shark is a planktivorous filter feeder (one of 3 species of shark in the world which feeds this way).
  • To feed, the basking shark opens its huge mouth and allows seawater to run through its massive gill rakers, where it filters out plankton (tiny microscopic species of plants and animals).
  • A feeding basker can filter around 1.5 million litres of water in one hour!

When to spot basking sharks in Ireland?

The best time of year to see Basking sharks in Ireland is between April and August when we also get high concentrations of plankton blooms. You can check for recent sightings and log your own on the Irish Whale and Dolphin Group website

Why do basking sharks breach?

Basking sharks have a similar body shape to the highly misunderstood great white shark even though they can be twice as large as a great white shark. They have also been seen exhibiting similar behaviours such as breaching the surface, although we are not sure why they do this. Great white sharks generally breach the surface when they are hunting, as they are ambush predators and attack their prey by accelerating at great speeds from below.

Basking sharks feed by swimming along slowly with their mouths open, so why do they breach the surface? It could be to remove parasites or it could be a form of communication, at the moment we just don’t know. Key traits such as their growth rate, length of pregnancy (fecundity) and where they give birth have been studied but they are still largely unknown.

New basking shark activity captured in Ireland – what does that mean?

Mysterious circle formations of basking sharks have been seen in Irish waters and scientists are only beginning to figure out what this could mean. They have found that these groups of the usually solitary basking shark are three-dimensional and run deep down into the water column. They believe that they could be witnessing a courtship ritual as there were equal numbers of males to females and the animals were not feeding. How this natural wonder has remained undiscovered for so long makes you wonder how much more there is to learn about these gentle giants.

Some more new exciting research has come out this summer showing that basking sharks are regional endotherms which means this huge fish is able to regulate its body temperature! This is exciting as many shark and fish species that can regulate their body temperature are usually fast, predatory fish (whereas basking sharks are capable of bursts of speed they usually cruise through the water at a much slower rate). This new link makes us question what we know about sharks and body temperature! What else don’t we know about these gentle giants of the sea?

Why do Basking sharks need protection?

Basking sharks are considered globally endangered on the IUCN Red List. Their oily liver, which takes up around 25% of their entire body weight is one of the reasons this animal was historically fished to near extinction. The oil from basking shark livers was used to heat and light homes across the world for decades before electricity was common practice. After this, they were then targeted for their large and distinctive fins, which could sell for up to $50,000 on the black market.

New protections for basking sharks in Ireland

The good news is that from the 3rd of October 2022 basking sharks in Irish waters were granted legal protection under Section 23 of Ireland’s Wildlife Act. This is a big step for basking shark protection as it is thought that up to 20% of the world’s population of basking sharks can be found in Irish waters.

There is an Irish saying which sums up the beautiful animal perfectly, it is ‘Chomh sámh le liamhán gréine’ which means ‘As tranquil as a basking shark’.

The Irish Basking Shark Group has lots more information on these gorgeous creatures including a code of conduct on how to observe them without disturbing them.


While this protection is a milestone moment for marine conservation in Ireland with legal protection being granted to a fish for the first time, the Wildlife Act offers protection in name only. With a lack of monitoring and enforcement, there is no active protection for these gentle giants. Marine Protected Areas (MPAs) however offer the opportunity to manage, monitor and enforce environmental protection. Fair Seas is campaigning to ensure the Irish government stay on track to hit its target of protecting 30% of Irish waters with MPAs by 2030.

To really allow for wildlife and ecosystems to recover 10% of Irish waters must be within fully protected MPAs, meaning no human activity is permitted. It is now no longer sufficient to merely protect our remaining wildlife. As stated in the 2022 Living Planet Report by the World Wildlife Fund, wildlife populations globally have declined on average 70% in the past 50 years, due to human activity. This is why we need to remove human activity altogether from at least 10% of our ocean to ensure that the species and habitats are allowed to exist undisturbed. 

Tanya Steele, chief executive at WWF-UK, said;

“Despite the science, the catastrophic projections, the impassioned speeches and promises, the burning forests, submerged countries, record temperatures and displaced millions, world leaders continue to sit back and watch our world burn in front of our eyes.”

Marine Protected Area legislation is being developed by the Irish government however the process needs to move more quickly if we are to effectively meet our targets and turn the tide on biodiversity loss in the ocean. Fair Seas is campaigning to ensure the ocean, our greatest source of biodiversity and most powerful climate ally, is given the protection it urgently needs. 

Fair Seas hosted the inaugural World Ocean Day conference in June 2023. We welcomed ocean advocates, government, industry and key stakeholders together, to map out the next steps for Marine Protected Areas (MPAs) in Irish waters. If you missed it or would like to revisit the sessions which took place, our conference recordings are now available to view on our Youtube channel.

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