A pod of dolphins is being credited with saving a group of lifeguards from a circling great white shark.

Lifeguard Rob Howes, his daughter Niccy, 15, Karina Cooper, 15, and Helen Slade, 16, were swimming 100m out to sea at Ocean Beach, near Whangarei, when seven bottlenose dolphins sped towards them and herded them together.

"They were behaving really weird," Mr Howes said, "turning tight circles on us, and slapping the water with their tails."


Mr Howes and Helen Slade had drifted about 20m away from the others when a dolphin swam straight at them and dived a few metres in front of them.

"I turned in the water to see where it was going to come up, but instead I saw this great big grey fish swim around me," said Mr Howes.

The veteran lifeguard said it was undoubtedly a 3m-long great white shark.

"It glided around in an arc and headed for the other two girls. My heart went into my mouth, because one of them was my daughter. The dolphins were going ballistic."

The 47-year-old said the dolphins herded the swimmers - who are all members of the Whangarei Heads Surf Lifesaving Club - back together and circled protectively around them for another 40 minutes, fending off the shark.

"I swim with dolphins perhaps three or four times a year here at this beach and I have never in six years seen them behave like that."

Mr Howes decided not to tell the three girls a shark was sharing the water with them.

Lifeguard Matt Fleet was patrolling out from the surf beach in a rescue boat and saw the dolphins' unusual behaviour.


He dived out of the boat to join the group and also saw the great white.

Mr Fleet said the water was clear and he had a good view.

The encounter occurred on October 30, but Mr Howes has spoken publicly about it only this week.

"I sat on it for three weeks, purely because I did not know quite how to handle it.

The only reason he went public was "I didn't want anyone to get chomped [by the shark], so I couldn't be accused of not having made people aware there was a shark out there".

Dr Rochelle Constantine, from the Auckland University School of Biological Science, said it was a rare event, but she had heard of similar things happening overseas.

She said sharks were not normally a threat to New Zealand's bottlenose dolphins, but the dolphins would attack them if they felt at risk.

"From my understanding of the behaviour of these dolphins they certainly were acting in a way which indicated the shark posed a threat to something. Dolphins are known for helping helpless things. It is an altruistic response and bottlenose dolphins in particular are known for it."

Ingrid Visser, who has studied marine mammals for 14 years, said there had been reports from around the world of dolphins protecting swimmers.

"[The dolphins] could have sensed the danger to the swimmers and taken action to protect them."

* Three orcas stranded themselves on Taiharuru beach, north of Whangarei, yesterday morning. Ms Visser said they were refloated when the tide came in and were unhurt.

Tale of the tape

* Bottlenose dolphin

Length: 1.9 to 4.2 metres.

Weight: Average 250kg, but up to 650kg.

Diet: A varied diet of fish and squid. An adult bottlenose dolphin may consume 8kg to 15kg of food a day.

* Great white shark

Length: Can grow up to 7m but commonly reach 4m to 5m.

Weight: Up to 2100kg.

Diet: They eat almost anything that swims, including people, although their main food is seals.