But they would reopen the investigation if new evidence was brought forward, a Doc spokeswoman said.
A member of the public contacted Doc on April 27, after discovering three breeding pairs and two juvenile penguins dead in a cave at the beach.
She believed they had been mauled to death by a dog.
She was helped by some fellow community members to bury the penguins in the sand dunes, she said.
Doc staff visited the site in the following days, but no penguins or signs of disturbance were located in the cave or in the sand dunes.
Subsequent searches also failed to uncover any evidence.
A Doc spokeswoman said it did not mean the incident was being treated as a hoax.
Rather, staff had just run out of lines of inquiry to pursue.
‘‘I think there was all kinds of speculation on social media, but we're not going to get down in the weeds on that.
‘‘We've got no reason to believe that [speculation].
‘‘We did an investigation, but we haven't got any further leads to go on for the moment.
‘‘But if anything else comes to light, then we'll certainly reopen it.’’
Staff have called for more information from the public, specifically photographs or information about where the dead penguins might be.
Without any evidence, Doc was limited in how it could progress with the investigation.
If you know something, or know someone who does, please get in touch with Doc.
Dog attacks on vulnerable native species had devastating consequences and Doc reminded owners to do their bit by always keeping dogs under their control, familiarizing themselves with the dog rules in the area and heeding the signage in place.
