The dolphin carcass came ashore at Newgale beach in late February, with seals ranging across the sea between south Wales and the Devon and Cornwall coasts identified as prime suspects. This case fits a pattern that has been building along British coastlines, where earlier in January, witnesses observed a grey seal holding a common dolphin in its jaws in the Irish Sea off Dublin, and Devon waters saw two comparable incidents before the year was out. Across the British Isles, researchers have reportedly linked 20 named individuals to this type of attack, each identified through unique scarring on their faces, though the concern among scientists is that this hunting technique is not staying within those individuals but spreading. According to Dr Izzy Langley of the University of St Andrews, the documented figure of 20 animals is a major underestimate, while seals displaying the same behavior have turned up across the North Sea as far as the German coastline.
Britain's grey seal population has recovered from roughly 500 in the early twentieth century to around 120,000, with scientists tracing the roots of dolphin predation to cannibalism. Male seals compete fiercely for mates between September and January, going without food throughout, and studies suggest some seals began targeting pups as a source of sustenance, tearing into the fat beneath the skin and moving on without consuming the rest. Scottish researchers monitoring the behavior over ten years recorded the rate of grey seal cannibalism doubling and then some between 2015 and 2016, and the behavior was first observed in Canadian waters in 1992, off the coast of Nova Scotia.
Seals are no match for dolphins in open water, as dolphins are significantly quicker, raising questions about the specific forensic methods used to confirm the seal attack in Pembrokeshire and the environmental factors driving the spread of this hunting behavior. The total number of grey seals estimated to be engaging in dolphin predation across the British Isles and North Sea remains unclear, as does the impact on common dolphin populations in affected areas.