A woman who allegedly struck Moko the dolphin with a waka oar will not be prosecuted, the Department of Conservation (DOC) says.
The incident apparently happened in Omaio Bay, 56km northeast of Opotiki, on January13.
DOC East Coast and Bay of Plenty conservator Henry Weston said today an investigation team could not find sufficient evidence to pursue the matter in court.
The option of a formal warning was also dismissed due to lack of evidence, he said.
"The legal and social issues are not straightforward when we are dealing with a dolphin that actively seeks out human interaction."
Mr Weston said the public should exercise caution in any interaction with the dolphin and DOC would pursue any reports of intentional harassment.
Moko was in good health and behaving normally, with no visible signs of injury or trauma, he said.
Moko recently followed a boat from the Gisborne coast, where he was a major tourist attraction since 2007, to the eastern Bay of Plenty.