"CPR was performed for 40 minutes and medical staff did all they could to save him, but he died in hospital.
"This is terrible news for the family of the young man who died."
Shepherd called the attempted rescue "an instinctive display of humanity".
Hughes' death followed an incident on December 16 involving a group of teens swimming down from the Taupō Control Gates bridge.
"The group split up, and due to confusion and miscommunication, it was thought that one of them had got into difficulty.
"That prompted a full-scale search involving a helicopter.
"Fortunately, the person thought to be in trouble was found to have already returned home."
Shepherd said while the events were unrelated, they underlined the risk the river presented to the public and rescue teams who are called in to help.
"These incidents also have a profound impact on the bystanders in the area, as well as the first responders who attend," he said.
"We're not out to stop anyone from having fun, but we want people to pause and consider: if you're getting in the water, are you confident of getting yourself out?
"The last thing we want is for anyone to be in distress, or at the very worst, not survive."
He encouraged people to pay attention to the dangers and the signs posted by the river and remember rivers can have a powerful pull.
