Gamekeeper and Wild Side of Jura volunteer Scott Muir, 32, found the animal struggling on the island hillside.
He said the stag was likely to have got his antlers caught in the plastic banding while grazing on seaweed on the coastline.
He believed the stag then walked for about a mile on to the hillside before reaching his final resting point.
It is feared the animal was trapped in the discarded strapping, going without food as his mouth was jammed closed by debris, for a week before he was discovered on Wednesday November 13. The animal had to be put down.
Wild Side of Jura, which aims to protect the west coast of the island, shared the images online, saying: 'A sad day today on the west coast of Jura. We came across this poor stag who was still alive and tangled up in this mass of plastic banding.
'He had managed to make it a mile up from the shore, no mean feat considering it was tangled round his back leg as well as round his antlers.
'Plastic waste is an increasing problem with more turning up every year on the west coast.'
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