Heartbreaking images show a bloodied seal with plastic netting wrapped so tightly around her neck it cut through her skin.
The wounded female was found on the Norfolk coast by a photographer hoping to capture photos of the animals for an annual calendar.
The pictures – taken at Blakeney Point, the largest seal colony in England – show the sheer scale of the plastic crisis and the saddening toll it takes on our marine species.
The species, the Atlantic Grey, seal is recognisable because of its snowy white coats and bug-like black eyes.
Paul Macro, a photographer from Norwich, spotted the helpless animal at Winterton-on-Sea and immediately ran to find a warden.
Mr Macro, 44, said that the seal was being guarded by a bigger male but was clearly in ill health and being strangled by the blue netting it had become entangled in.
‘It’s heartbreaking’, he said. ‘You can see its sadness.’
‘I didn’t want to approach it so I immediately found a warden from Friends of Horsey Seals.
‘In front of her, you can see a big male and it’s almost like he’s looking after.’
Mr Macro said that he phoned the volunteers for an update but unfortunately they said they hadn’t been able to rescue the seal.
Alison Charles, manager at the East Winch Wildlife Centre, who usually treats such cases, said volunteers hoped to be able to help the Atlantic grey soon.
She said: ‘There is fresh blood there and it looks like a really fine nylon netting to me.
‘I just want to get my hands on them all and help them,’ Ms Charles said. ‘It is frustrating but we do the best we can.’
Several other seals were discovered with similar injuries in the same area before Christmas.
Before Christmas, several seals were found in the same area with frisbees wrapped around their necks, which cut into them as they grow bigger.
One of the seals, nicknamed Mrs Pink Frisbee, was taken to the RSPCA centre at East Winch and is expected to be released next month.
The wildlife centre treated eight patients at its hospital and said the situation was getting worse.