On the 5 March, a 9.8 male sperm whale was reported to the IWDG Stranding Scheme by Eoin Hogan of the CLDC. An IWDG team visited the carcass immediately in order to gather baseline data from the animal, which includes total body length, gender, detailed images of the carcass, and a skin sample for the Irish Cetacean Genetic Tissue Bank, which is maintained at the National Museum of Ireland.
Stranded sperm whale. Incoming tide and fading light. Photo credit: Simon Berrow
Measurements and images of the tail fluke were taken and sent to Sean O’Callaghan, a PhD candidate at ATU focusing on sperm whale structure in the Northeast Atlantic, who shared them with colleagues in Norway and the Azores too determine if this is a known animal. However, due to the advanced state of decomposition of the tail fluke, no matches were made. Further reading on sperm whale photo ID can be found here: https://www.aquaticmammalsjournal.org/article/aerial-photo-identification-of-sperm-
whales-physeter-macrocephalus/
A partial post mortem examination was carried out by members of the IWDG team on 6 March and to obtain aerial images. Although the main stomachs could not be accessed due to diminishing light and an incoming tide, examination of the intestines did reveal fresh and copious excreta, suggesting the whale had been feeding well up to its death. A single squid beak was recovered.
Squid marks. Photo credit: Csilla Trungel
Sperm whale strandings along the Irish coast are rare, but not out of the ordinary. The IWDG Stranding Database currently has 104 records of stranded sperm whales, receiving an average of 2-3 per year. This animal in Clare represented only the 7th record from Co Clare and the first sperm whale stranding of 2025.
Stranded male sperm whale. Photo credit: Csilla Trungel
In the North Atlantic, male sperm whales move to higher latitudes as far as Svalbard, while females and young whales typically remain around lower latitudes, around the Azores, Madeira and the Canary Islands (O’Callaghan et al., 2024), which is likely why stranded animals of this species in Ireland are typically male. Interestingly, Barlie et al., 2023 processed hours of acoustic data from Irish offshore waters which revealed that large males did not account for the majority of the animals recorded in the area. However, to date, the IWDG stranding database contains significantly more males than females; 10 females, 52 males, and 42 of unknown gender.
Sperm whale fluke.
Further reading on studies carried out using records and samples from animals reported to the IWDG stranding scheme can be found here:
https://www.jstor.org/stable/45181669
https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.70056
Frontiers | Click-click, who’s there? Acoustically derived estimates of sperm whale size distribution off western Ireland
Stephanie Levesque and Simon Berrow
IWDG