A man was injured when his catamaran collided with a whale in Durban on Saturday, the National Sea Rescue Institute (NSRI) said.
Derrick Pienaar (50) had fractured the bone in his upper right arm, NSRI spokesman Craig Lambinon said.
"Mr Pienaar's injury was sustained after he fell on deck after the sport fishing boat, which he was a passenger on, struck a whale while the boat was underway."
There were seven other people onboard the vessel but only Pienaar was injured.
He was taken to the Umhlanga Hospital.
The catamaran was not damaged.
"Clifford Ireland, NSRI Durban station commander, said that while on-scene a whale came past the boats and it is suspected that this was the same whale that they had struck and... it appeared to not be injured," said Lambinon.