A seal that delighted eastern suburbs residents by taking up a new home at a Rushcutters Bay park has died of health complications.

The male Australian fur seal, nicknamed "Sealvester" on social media, was first seen almost two weeks ago at Rose Bay where he alternated between swimming laps and sunbathing in the harbourside dog park.

The seal's deteriorating health condition in recent days forced animal authorities to anaesthetise him to assess his condition, but he died on the way to Taronga Zoo.

Taronga Zoo veterinarian Kimberley Vinette Herrin said the elderly seal had been monitored closely for the past several days.