More seals are being spotted farther upstream in the River Thames, with one seal recently seen as far west as Windsor, according to conservation charity the British Seal Alliance.
An estimated 3,500 seals live in the River Thames, with most believed to remain around the estuary east of London.
Marmalade was considered a rare sighting because only around 500 harbour seals are thought to live in the Thames, compared with approximately 3,000 grey seals.
Gareth Richards of the British Seal Alliance said seals are highly mobile animals that travel to areas with strong fish stocks.
“Seals can swim between 60 and 80 miles a day,” he said.
Mr Richards said he would like to see stronger legal protection for seals as sightings become increasingly common along the River Thames.
Under the Wildlife and Countryside Act 1981, neither grey seals nor harbour seals are currently protected from intentional or reckless disturbance.
In May, the British Seal Alliance launched its Give the Seal Some Space, external campaign. The initiative calls on the government to reconsider previous recommendations and provide both seal species with the “legal protection they deserve”.
The campaign warns that seals are highly vulnerable to disturbance from people, dogs and drones.
Such disturbances can have long-term effects on seals’ health, including the abandonment of pups, unnecessary energy loss while remaining alert and injuries caused by panic-driven escapes.
The Department for Environment, Food and Rural Affairs (Defra) said: “We are introducing a range of legal protections that will make it a crime to take, harm, capture or kill seals.”
Source: www.bbc.co.uk