A man has been bitten by a shark at Shelly Beach, Ballina.
A man has been bitten by a shark at Shelly Beach, Ballina. Liana Turner

Shark nets 'not effective': scientist responds to attack

A MARINE biologist has responded to yesterday morning's shark attack in Ballina.

Lee Jonsson, 43, remains in hospital after being bitten on the leg while surfing at Shelly Beach about 7am.

That beach and all in Ballina Shire have been closed for 24 hours.

Dr Daniel Bucher is an Associate Professor in marine biology and fisheries at Southern Cross University.

While a resident who's stopped surfing for fear of being attacked has called for the return of shark nets, Dr Bucher said this wasn't the answer.

"I think certainly the netting trial demonstrated very clearly that they're not very effective particularly given the high cost," Dr Bucher said.

"You can present all the scientific data you like and people will still hold to their opinions.

He said the "high cost" of shark nets was both economic and environmental; most of the impact from the nets was by-catch of non-target species.

"I think the SMART drumlines have a role to play particularly in protecting events like surf festivals and so on," he said.

"(On an ongoing basis) I don't think they're particularly effective for the amount of money that's spent ... but they don't have the same by-catch as nets."

Dr Bucher said in the second trial, the DPI tried different meshing methods to try to reduce bycatch, but the results were worse.   

He said other methods, like eyes on the beach from Surf Lifesavers and lifeguards, including drone and aircraft surveillance, were more promising and had the "side benefit" of helping to prevent drownings and other incidents along the coast.

He said he hadn't noticed first-hand a spike in sharks on the North Coast of late, but had noted "a lot of alerts" on the Shark Smart app, which maps the location of tagged sharks.

There are seasonal changes in shark numbers, and Dr Bucher said great whites were less abundant in the warmer waters at this time of year, but still present.

"They're still here all year round," he said.

He said bullsharks and tiger sharks were generally seen in higher numbers as the coast warmed throughout summer.

The Department of Primary Industries has not identified the species of shark involved, but a spokeswoman said a shark biologist would examine the 43-year-old man's leg wound to attempt to do so.

Despite any mitigation methods put in place, Dr Bucher said it was important to remember whose environment the ocean is at heart.

"We've just got to get used to the fact we've got a healthy marine ecosystem and that's going to support top predators," he said.

"When we enter that environment we need to fit into it, rather than make it fit us."