Marineland's longtime manager Gary Macdonald has resigned following an investigation by the Napier City Council.
The marine zoo and hospital came into the spotlight recently after they were found to have provided false documentation regarding the holding of three New Zealand fur seal pups.
Napier City Council chief executive Neil Taylor investigated the matter under the terms of the Employment Relations Act.
Mr Taylor concluded that the documentation relating to the pups was incorrect and misleading as it stated the pups were born at Marineland instead of brought in from the wild.
The pups were brought into Marineland on three separate occasions in 1996, 2006 and 2007, all of them being malnourished or at risk.
Under the terms of Marineland's permit the pups were permitted to be treated at the facility but DoC staff were to be notified. This did not occur.
Mr Taylor said the seals should also have been identified in future documents as having been taken from the wild. "Deliberate decisions were made to identify the seals as zoo-bred," he said. Neither Mr Taylor nor Mr Macdonald would comment as to why this was concealed.
The three seals are still at Marineland.
Mr Macdonald, 60, resigned on Wednesday, adding that he "absolutely" took full responsibility over the issue.
"I'm comfortable to do that," he told Hawke's Bay Today. "It has been a difficult decision, but ultimately the right one."
He did not want to see Marineland or the council blamed for the actions of one person who had made a "serious error in judgment".
Mr Macdonald, who has been at Marineland for 37 years and manager for 32, said he had hoped to be there when the centre's "ongoing issue" over the potential redevelopment was resolved but this was not to be the case.
He finishes at Marineland on November 27 and is unsure about his future plans.
"The fact I've resigned after 37 years is pretty high impact for me."
Mr Taylor said his investigation was now complete and no further action would be taken.
DoC also undertook its own investigation but said it was unlikely any prosecutions would be brought against Marineland.
Mayor Barbara Arnott said it was an "unfortunate series of events ... which has culminated in the resignation of somebody who has given good, long service to the council".
Friends of Marineland chairman Cliff Church said Marineland was losing one of its "greatest assets".
He believed that there had been potential for a different outcome.
"While I don't have all the facts in front of me I'm concerned that maybe this matter wasn't possibly thought through by both parties as well as it should have been before this decision was made."