Shark swoops in for meal

Just when you thought it was safe to go back into the water, a spectacular photo, believed to have been snapped off Kaiteriteri Beach near Nelson, appears to prove it is a shark-eat-shark world out there.

The image, posted on social media site Reddit, shows a small school shark on the end of a fishing line being chomped into by a much larger blue shark as it is about to be lifted into the boat.

Reddit user Mancubus uploaded the snap last Friday with the headline: ‘‘Caught a small shark ... next minute.’’

Within days the photo went viral and was published all over the world. With few details available about what happened, readers were quick to guess what was going on in the picture, with some believing the bigger shark was only trying to save its baby.

Others labelled it ‘‘reverse fishing’’, while a few said the photo had to be a fake.

Department of Conservation shark specialist Clinton Duffy, a marine scientist, said the shot had captured a common event.

‘‘Blue sharks often steal fish off people’s lines at this time of year, and they also commonly eat other shark species,’’ Mr Duffy said.

The school shark, a juvenile, was probably about 80 centimetres long, while its bigger enemy was about two metres, he said.

Both were common species in New Zealand waters, although the blue shark was becoming a rarity due to the practice of shark finning. ‘‘It’s quite encouraging, really, to see a picture like that,’’ he said.

And if you are wondering why the sharks have white eyes – it is because of a special membrane that protects their eyes as they go in for the attack.