There is a “distinct possibility” harbour seals could be wiped from the Norfolk coast due to a disease, an animal charity said.
The seals, also known as common seals, were suffering from mouth rot, which caused mouth lesions and ulcers in newly weaned pups.
Sally Butler, chairperson of Friends of Horsey Seals, said the group had euthanised 25 pups this year due to the condition, which had been “totally heartbreaking”. Some cases had also been reported in Suffolk.
Dr Jamie Bojko at the National Horizons Centre, Teesside University, Durham, was investigating the cause of the disease along with the Department for Environment, Food and Rural Affairs (Defra).