A spooky shape in the ocean at Ruakaka Beach is almost certainly a bronze whaler, says a shark expert.

Aryan McKay captured the photo after she got her family out of the water on December 2.

Department of Conservation marine scientist and shark expert Clinton Duffy said the shark was "99 per cent" a bronze whaler and people needed to realise that they were the most common shark around and were often in the water at the same time as swimmers.

However, Mr Duffy said, bronze whalers were fish eaters and did not attack swimmers.


"They have been known to have a go at spearfishers who have a dead fish with them, but you would have to be very, very unlucky to have any dealings with a bronzy if you are just out there swimming," Mr Duffy said.

"They are everywhere out there at this time of year, but there's very little danger to the public. The females start coming in from October to drop their pups and the males come after that. They feed on fish like kahawai, snapper and mullet, that are in the shallows in abundance at this time of year so aren't interested in us.

"But they are the reason spearfishers are told not to tie fish around their waist after catching it because a bronzy will have a go at the fish."

Mr Clinton said shark attacks were extremely rare in New Zealand.

"Surf lifesavers see bronzies all the time at this time of year."

Ruakaka Surf Lifesaving Club Captain Tania Ahrens said while sharks are always in the ocean they rarely come close to shore.

"There might be a bronze whaler cruising round and we will sound the siren and get everyone out but in my eight or nine years with the club I've never seen them take much notice," she said.