What did this? Australian fisherman catches three half-chewed sharks

 An experienced Australian fisherman has reeled in three sharks, with each one bitten entirely in half by a much bigger shark.

Professional angler Jason Moyce caught the haul of a bronze-whaler and two hammerheads off the coast of Bermagui in southern NSW.Mr Moyce said on Facebook, where he goes by Trapman Bermagui, that he wasn't able to get a whole shark back to the boat while out fishing on Wednesday. 

'Plenty of smooth hammerheads around but getting a whole one back to the boat is a challenge,' Mr Moyce said after catching a second chomped shark.

A bronze whaler shark bitten in half (pictured) by what angler Jason Moyce assumes was a 'big unit' tiger shark on Wednesday 

Mr Moyce and his employee reeled in two hammerheads sharks bitten in half (pictured) 

When he reeled in a third Mr Moyce - who has decades of professional fishing experience - decided to call it quits. 

'Even the bronzies (bronze whalers) aren't safe today. No more shark fishing for us. Too many big units around,' he said.

He said that he reckoned tiger sharks were responsible, although he couldn't be sure, and that he has had similar experiences in recent years with sharks tailing his fishing boat looking for an easy source of food.

There has been an increase in shark attacks in recent years with one theory stating that sharks are more active in warmer waters.

Scientists from the UK in a 2018 study found a water temperature of 22C was preferred by tiger sharks.

'Our study suggests that 22C is not too cold for the animals and it's not too hot for them,'Dr Nicholas Payne of Queen's University Belfast and the University of Roehampton said.

Mr Moyce (pictured) said the sharks will often trail the boat looking for an easy meal 

He said if ocean waters rise even by one or two degrees this could impact shark populations.

'Places like Sydney might start to see more tiger sharks during winter months whereas at the moment you very rarely see tiger sharks in Sydney in winter,' he said.

Australia's La Nina summer is in part caused by warm surface water pooling in the western Pacific Ocean.