On Tuesday last week a sighting of a white shark close to shore at Shelly Beach closed beaches from Nambucca Heads to Valla Beach for 24 hours.

Three days later beaches had to be closed again - this time for 48 hours - after multiple sharks were seen swimming in the same area.

Local fishermen have said that on Sunday night two great whites were caught near Horseshoe Bay at South West Rocks.

Two weeks ago surfer Chantelle Doyle had a heart-racing encounter with a juvenile white which locked onto her leg at Shelley Beach, Port Macquarie. Her partner, Mark Rapley, repeatedly punched the shark until it detached its grip.

Chantelle thankfully survived that encounter, but has already had two operations, with more planned, and doctors are unsure if she will regain feeling in her leg.

And back on May 19, Tony Lenthall caught this juvenile white at Grassy Head as by-catch while fishing for other species. It was quickly released after this snap.

Yes, the ocean is a shark's native environment. And yes, they're nearly always present near swimming beaches and popular fishing spots, without anyone ever spotting them.

But great whites are generally a rarity in these waters - they prefer water temperatures cooler than ours, somewhere between 12 and 24 degrees.

Southern Cross University Marine Biologist Dr Daniel Boucher said white sharks are usually only seen in the winter months here, when they have a tendency to move up the east coast away from the cooler waters down south.

"They often chase the spawning runs of things like salmon, mullet and tailor," he said.

While many speculate that the annual whale migration increases sharks' presence, Dr Boucher said that theory just doesn't stack up.

"What we've been seeing recently are juvenile white sharks, which are not influenced by whale migration," he said.

"Plus whale carcasses are not a reliable enough source of food to affect shark migration.

Local father-son fishing duo Tony and Jason Didio operate Didio's Country 2 Coast fishing charter business and can be out on the water up to three times a week.

They said the closest bait school reef is only a couple of hundred metres off Shelly Beach, "which is a great food source for sharks".

They also said the almost tropical water we've had over the past five or six years means many of the migrating schools haven't been running up this far.

But that's all changed this year; the cold waters have pushed up again and both men have been astounded by the sheer bulk of the salmon schools they've been witnessing over the past couple of weeks.

And salmon and mullet have a tendency to cruise along the shoreline instead of pushing in closer at dusk like other schools.

"It's been amazing to see the salmon up on shore and the sharks follow them right in," Tony said.

Tony has been fishing in the area for around 18 years now, and said he's only ever had the pleasure of seeing about four or five great whites in all that time. So this year has been special for him.

"They're absolutely beautiful animals," he said.

"The tigers and the bulls are the ones that will come up and have a go. The great white cops all the blame though.

"Yeah, if I had a choice between being in the water with a tiger and a white, I'd choose the white any day, knowing now what tigers are like," Jason said.

According to local fishermen, it's not just the whites that are more numerous this winter.

"There have been huge dusky whalers - we're talking 12 to 14 footers - between Valla Headland and Urunga," Tony said.

"A lot of the pros are saying they've never seen sharks this big there before."

And Jason and Tony have a theory as to why.

They think regulations brought in over the past decade mandating the use of monofilament line, and introducing shark quotas, have made it unfeasible for commercial fishermen to continue to catch them. They believe this has bolstered shark populations in recent years.

"The number of sharks we've got right now is nothing compared to what we will have in January, February," they said.

The best form of defence is a healthy respect and dose of social distancing.

Dr Boucher said it's obviously not a good idea to be in the water if it's known there's a white shark present.

And the old logic of 'don't go in at dawn and dusk' doesn't necessarily hold up for white pointers.

"Those sorts of rules don't hold true to all species of shark. We know white sharks will feed at any time of the day," he said.

Jason and Tony can confirm this. But still say there's wisdom in avoiding the water at sun-up and sun-down.

"Sharks might feed at any time of the day, but dusk and dawn is when the bait fish are on the banks - so that's when sharks will be more active around the shoreline," they said.

Tony said sharks don't view humans as a tasty morsel.

"They're not out to eat us though - after they bite you, they never come back for a second go."

They said it's important to scan the water for large black patches - which are likely to be schools of bait fish - and birds diving nearby.

"If there's bait, there's a very good chance there's a shark nearby," Tony said.

Dr Boucher said while drones and smart drums are "somewhat helpful" shark mitigation efforts at popular beaches during the swimming season, they're not a good way to reduce the overall risk on a larger scale.

He said personal Shark Shield electromagnetic repellant devices - with electrodes that can now be attached to board fins without clunky wires - are currently the only proven device which works at repelling sharks.

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