Members of the Otter Network first spotted the animal in Tyneside in January, and contacted the International Otter Survival Fund (IOSF) based on the Isle of Skye for advice.
There were several sightings over the next few weeks and a trap was used to catch the animal, which was finally rescued near Wallsend Hall on February 26 and taken to a vet for treatment.
The otter, a female, has a serious wound and is now recovering at the RSPCA’s Stapeley Grange Wildlife Centre.
It is hoped that she can be released soon.
IOSF said the otter would almost certainly have died if the restriction, which turned out to be a fishing line, had not been removed.
A spokeswoman said: “If the animal wasn’t caught and the cable tie/fishing line removed it would almost certainly suffer a long painful death.
“There were several sightings in various parts of the Tyneside area and so it was a longer process than had been hoped and a licence also had to be obtained in order to catch the otter.
“Otters are naturally wary of traps and we didn’t want it to be scared away and then have to search for it again.
“So camera traps were used and showed the otter investigating the trap before it was actually set.”
The charity warned of the dangers that litter can pose to wildlife.
IOSF said: “Unfortunately, this is not an isolated incident and IOSF has received casualties such as this which have been caused by cable ties, fishing line and also snares.
“Litter can cause such terrible injuries and it is largely because of carelessness that people just leave it.
“Sadly, there isn’t always a ‘happy ever after’ and many animals and birds die as a result.”
The latest rescue was a collaboration between IOSF, the Otter Network, UK Wild Otter Trust, RSPCA and the vet.
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