Senior Constable Graham Perkins, of Alexandra, said the Alexandra angler had just arrived for an evening fish about 6pm on February 6.
He noticed the man in the water and as he floated closer with the current the fisherman was able to pull him up on to the riverbank, Snr Const Perkins said.
The fisherman began CPR and contacted emergency services who were able to guide him with resuscitation until St John and fire service staff arrived about 15 minutes later.
An Otago Southland rescue helicopter was sent from Dunedin and a paramedic was winched down to the patient. Once the patient was stabilised he was winched into the helicopter with the paramedic and flown to Dunedin Hospital with possible water inhalation and hypothermia.
Unfortunately the man died the following morning.
It was not known how the deceased ended up in the river or how long he had been there. His vehicle was nearby, he said.
Police and emergency services praised the actions of the fisherman for performing CPR in an isolated location by himself until medical personnel arrived. The fisherman said it was not something you expected to come across when you went fishing.
"The people on 111 were really good giving me help and instruction, as I was by myself."
