Warning: This article contains images that may disturb some people.
A young fur seal has suffered severe injuries after being trapped by a "noose" of fishing line, which left it with deep lacerations to its neck.
Its injuries sparked a major rescue mission on Wednesday to save the seal's life, and a powerful message about the damage marine plastics are doing to our environment.
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Sakula Costar was taking a walk with her partner on Piha Beach when she noticed a "skinny and exhausted" fur seal on the right side of Lion Rock.
"When I looked closer, I noticed the fur looked different around the neck - so I approached it to investigate," she told Newshub.
"I knew something was wrong when he didn't immediately jump back into the water. He looked up at me, and I could see the suffering and desperation in his eyes."
To her horror she found a fishing line tangled around his neck, which had been there so long it had cut deep into its flesh.
"My guess is that it got stuck there when he was smaller, and it slowly got tighter and tighter as he grew bigger," Ms Costar told Newshub.
Fortunately, she and her partner found a pair of scissors in the car and decided to try and cut the line. Normally this would be a difficult and dangerous procedure, but the seal had been fighting for so long he was exhausted.
"He held still and barely flinched while I gently cut the line, which is amazing because wild animals usually don't want you anywhere near them," she says.
"It's like the seal knew what I was doing, because he tilted his head back and showed me a part of the line that I could cut."
She called the Department of Conservation, which sent biodiversity ranger Gabrielle Goodin out to assess the seal.
"I thought it was dead when I saw it. It didn't look good," she told Newshub. "There were flies hanging around the seal."
Together with a specialist team from Auckland Zoo, they managed to come with a plan to grab the seal and move it to safety.
"It has a deep encircling laceration to approximately 80 percent of its neck," Auckland Zoo resident vet Dr Lydia Uddstrom says.
"Any wound like this make it vulnerable to infection - and with infection, there is then always the risk that it can spread to other parts of its body."
The seal has been taken to Auckland Zoo, where it remained in a "critical condition" on Thursday.
"We were expecting it might not come back out of the zoo," Ms Goodin says.
The seal has been put on pain-relief, IV fluids and antibiotics, and will undergo a procedure to clean the wound on Friday.
"Our aim is to ensure it is well on road to recovery, and all going well, we hope to be able to release him back to the wild where he belongs in the not-too-distant future," Dr Uddstrom told Newshub.
"Sadly, we are once again seeing first-hand the impacts plastics in the marine environment can have on our precious marine life."
Ms Costar agrees, and she has a message for fishermen at the popular spot: please tidy up your mess.
"The rocks where they fish off is often littered with fishing lines and hooks," she says.
"I hope that this little seal's story will make people think twice before leaving rubbish lying around!"