Its head alone was over 16ft in length and around 8ft wide
Andrew Forgrave Countryside and tourism editor and Cheryl Mullin
12:31, 05 Sep 2025
The whale’s head measured 16ft long by 8ft across(Image: Marine Environmental Monitoring)
The remains of a massive sea creature that washed up on the Welsh coastline have been confirmed to be those of a “very large” fin whale by researchers. Only surpassed in size by the blue whale, this marks just the fourth verified report of a fin whale washing ashore in Wales this century.
It represents the first beaching since a young fin whale died two days after becoming stranded in the Dee Estuary, Flintshire, in June 2020. That incident involved a 41ft (12.5 m) calf – considerably smaller than the latest find on Cefn Sidan sands in Pembrey, Carmarthenshire.
Preliminary examinations suggest a female fin whale measuring nearly 70ft (21m) in length. Personnel from ocean monitoring body Marine Environmental Monitoring (MEM) were amazed by its enormous proportions when they visited the shoreline the day following its discovery on the morning of Wednesday, September 3.
The head alone measured over 16ft (5m) long and approximately 8ft (2.5m) across. In a subsequent update, MEM revealed: “Unfortunately, it had been dead for some time and as a result was in a bad state of decomposition.
“We believe that this one is a female but due to the state of decomposition we couldn’t confirm this. We have taken several samples from the whale which will be tested for various things including contaminates and to carry out genetics.”, reports North Wales Live.
In the past, whales beached along the Welsh shoreline have frequently been discovered to be undernourished or impacted by contamination such as plastic debris. Marine experts have reported an increase in fin whales returning to Welsh waters.
The remains of a fin(Image: Marine Environmental Monitoring)
According to research by the Sea Trust, pods are now regularly spotted off the coast of Pembrokeshire each year.
Wednesday’s discovery was the second of the week involving a whale. On Monday, September 1, a long-finned pilot whale was found on Rhossili Bay beach on the Gower peninsula.
Despite being alive when found, attempts by the public to return the whale to the sea were unsuccessful due to its weight. Coastguards and volunteers from British Divers Marine Life Rescue (BDMLR) were alerted, but sadly, the animal passed away before they arrived.
MEM identified this creature as a juvenile female measuring almost 9ft (2.7m) in length. The group added: “They can grow to be over 6m in length when fully grown and live up to 60 years.
One of the whale’s jaw bones(Image: Marine Environmental Monitoring)
“Pilot whales are social animals that live in large social/family units for their entire lives. Due to those social bonds, they are prone to mass strandings like the one that was seen last year in Scotland where 77 stranded together. We suspect that this one got separated from the family unit before finally ending up on the beach.”
The carcass has been recovered for the Cetacean Strandings Investigation Programme (CSIP), and a full post-mortem will be conducted.
MEM is encouraging the public to report any stranded marine animals to CSIP by calling 0800 652 0333. If the animal is still alive, select option 1 which will direct you to BDMLR.
If not, choose option 2 and follow the given instructions.