A second sea lion has died in just over a month at Napier's Marineland when 22-year-old Makea failed to recover from a general anaesthetic on Friday.
Fellow sea lion Rufus died on December 9.
A Napier City Council spokesperson said Makea had begun showing signs of being unwell for several days before his death.
Makea failed to recover from anaesthetic that had been given to him by veterinarians from Massey University who arrived to check him out.
He had been initially been "uninterested" in his food and was closely monitored by the Marineland vet.