Two giant ocean hunters chased the calf from its mother and launched a spectacular attack that lasted for almost an hour and was watched by three fishermen.

"The killer whales kept rolling over on top of the calf as the mother tried to protect it," Clark Smock told The Standard yesterday.

"It was very spectacular. They were sailing nine feet out of the water. In all my years at sea I've never seen anything like it before.

"At one point we could see the mother slapping around, probably very anxious."

Mr Smock, a former abalone diver, took friends Bruce Black and David Hounslow out on a snapper fishing trip last Thursday when they noticed the spectacle about 500 metres away in the bay.

Mr Hounslow described the killer whales' fins as "like the conning towers of a submarine".

"The killer whales looked like they were set to have lunch," he said.

"They seemed to be giving the whale and calf a hard time. We certainly saw quite a lot of activity from the killer whales."

Mr Black said at first it looked like all the whales were southern rights, but it became obvious killer whales were trying to separate the calf from its mother.

"There was a lot of activity then they dispersed."

It appeared the calf survived the ordeal as there were no reports of a carcass on local beaches and three sets of mothers and calves were reported off the south-west coast this week.