The National Sea Rescue Institute (NSRI) said one fisherman was still missing on Monday after a fishing vessel capsized at St Helena Bay on Sunday night.
In a statement, Mike Shaw, NSRI Mykonos duty controller, said several of the institute's rescue crafts were launched at about 16:45 on Sunday in an effort to reach multiple fishing boats that requested fuel, after they had run out.
He said at one stage 10 boats had reported fuel starvation in fading light.
"The NSRI sea rescue craft Gemini Rescuer II diverted to assist the fishing vessel Normandie, 10 nautical miles north of St Helena Bay and 10 nautical miles off-shore, reporting to be under tow by a fellow fishing trawler but taking water from being heavy laden with fish in rough sea conditions and strong winds with eight crew on board," he said.
Shaw said as the rescue craft approached the Normandie, it capsized, and seven of the eight crew abandoned the vessel as it rolled over.
"Seven casualty crew of Normandie were immediately rescued by NSRI from the water and transferred onto the fishing trawler that had been towing Normandie and they were not injured. One fisherman was last seen on the Normandie as she capsized and despite an extensive search by three NSRI sea rescue crafts and fellow fishing boats, no sign of the man has been found," he said.
Police divers will continue ongoing search efforts and an investigation has been launched, Shaw added.
He said police and Western Cape health emergency medical services had also responded to the incident to assist NSRI controllers.