Taronga Wildlife Hospital has confirmed that Sealvester, the sunbathing Sydney seal, has died.
The Australian fur seal first popped up in Rushcutters Bay close to two weeks ago and quickly became a favourite with residents and visitors alike.
But vet officers decided to intervene after noticing that the seal, who was underweight, had eye and flipper wounds that required treatment.
Sadly, Sealvester died in the van on the way to the hospital after being sedated.
"We saw he had lost quite a bit of weight so we anaesthetised him to examine his eye and flipper wounds with the aim of having a look at him a little closer," Taronga Zoo vet officer Kimberley Vinette Herrin said.
"He was about 140kg. A seal that age and size should probably weigh 205kg or a little more."
While Ms Herrin admitted that the anaesthetic may have contributed to Sealvester's death, she defended the team's actions.
"The last thing we wanted for him was to slowly deteriorate and die a really uncomfortable death," she said.
Shona Lorigan, a volunteer with the Organisation for the Rescue and Research of Cetaceans in Australia (ORRCA), told ABC News that the seal's condition had been worsening.
"Over the last couple of days we've watched his condition deteriorate, particularly his eye wound," she explained. "And his body condition has also gone downhill."
Sealvester was first spotted sunbathing in the popular dog-walking area on March 24, prompting City of Sydney to construct a temporary fence at the base of the ocean steps.