Conditions were very rough with large waves breaking on the beach and washing over in the lagoon.
The search resumed at first light this morning, but an early helicopter search found no sign of him and hopes of finding him alive are fading. Land Search and Rescue volunteers from Rakaia are using quad bikes to search the south side of the river mouth, and volunteers from Ellesmere are searching the northern banks
Coastguard Canterbury Air Patrol will also conduct an air search along the shoreline using a fixed wing aircraft.
"It's not looking good at all,'' said police search and rescue co-ordinator Sergeant Ryan O'Rourke.
Mr Boraman's family had travelled to the south side of the Rakaia River mouth this morning.
His parents arrived shortly after 10am and they tearfully met their son's friends and police.
The death would be referred to the coroner in due course, police said.