But just finding the giant predators is the first problem, says veteran shark tracking scientist Jonathan Werry.

NSW recently announced it would fund a major shark tagging program in response to a series of attacks in waters off the north coast.

Such programs can provide excellent insight into the animals habits, as Dr Werry's research has demonstrated: He was able to find a correlation between rainfall amounts in catchments and when bull sharks are likely to turn up along popular beaches.

The NSW Department of Primary Industries says it has set aside $250,000 to undertake a range of attack prevention measures, including tagging and increased shark spotting programs.

But so far it has refused to provide Fairfax Media with details of the program and how much of $250,000 will go towards this research, and whether it's enough.

The department is also refusing to provide detail about exactly what tracking resources it already has in place in the attack-prone waters of northern NSW, where two people have died and another two were severely injured.

In order to track sharks or other marine animals, scientists rely on two main types of tags – satellite or acoustic.

The most expensive are the satellite trackers, which are capable of keeping a record of the animal's movements and then sending the data in a burst to a receiving satellite when the shark surfaces.

The other, an acoustic tag, relies on a network of receivers located on buoys or other devices anchored in the water and records the passing of a tagged animal.

Receivers for the acoustic tags often have to be physically recovered to download the data, which can take time and be expensive if the device is located in a remote area.

The department already has more than 700 receivers, including buoys and other devices, located around the state in order to track sharks, turtles and seals  for research.

And the positioning and operational status of most of the devices are listed on the publicly searchable Animal Tracking and Monitoring System (AATAMS) a national collaborative research facility supported by the federal government.

However, this week, a check of the AATAMS' list states that while the department had 17 buoys positioned north of Coffs Harbour where the attacks have occurred, only one was listed as operational.

This operational buoy was located in the mouth of the Clarence River – about 30km south of a shark attack at Evans Head earlier this month.

When asked to confirm which if any of 17 devices was operational, the department refused to say.

A spokeswoman responded with: "We continuously review their locations and reposition them as necessary to gain the most data and knowledge about the species out of interest".

A number of the department's acoustic tracking receivers are also attached or associated with fish aggregating devices, which are man-made floats tethered to the ocean floor that are designed to attract pelagic fish.

AATAMS lists the department as having had receivers associated with fish aggregating devices off the coast at Ballina and Byron Bay but that the devices were not in operation and had since been retrieved.

A DPI spokesman said the devices were removed from the ocean during the winter season for maintenance to ensure their longevity and also ensure they don't interfere with the whale migration season.

In the past 11 months, four attacks have taken place in the waters between Evans Head to Byron Bay and, on Saturday, Dale Carr was mauled off Port Macquarie, on the mid-north coast Coast of the state.

In the Evans Head attack in August, father of three Craig Ison was bitten and nearly died while surfing after punched away a suspected great white shark.

The attack came about a month after body-boarder Matthew Lee was severely injured by a shark at Lighthouse Beach, Ballina.

Six months before, Japanese surfer Tadashi Nakahara was killed in what was believed to be suspected great white shark attack at Shelly Beach at Ballina.

And in September 2014, British citizen Paul Wilcox died when he was bitten as he swam just off the beach at Byron Bay.

When asked this week how much of the $250,000 would go towards tagging and tracking sharks and how much would be spent on other prevention measures such as aerial patrols and other measuress, the department declined to comment.

Dr Werry, who has been tagging and tracking bull sharks for several years, estimates it costs about $10,000 to catch and tag a shark, provide a satellite tag and then to pay for the satellite time and process the data.

But he says despite the expense and time, the research can be highly useful: his monitoring of bull sharks around the Gold Coast has uncovered important information about their movements, including that animals travel as far south as Sydney Harbour.

More importantly, tracking has led to the potential correlation of rainfall patterns with bull shark feeding zones, with data suggesting that for 100mm of rainfall in a catchment system, there would be an eight-day window of bull shark activity in the muddy water flowing out of the catchment into the ocean, attracting not just sharks out of the river systems but also larger animals coming in to feed.

He said people need to understand that tracking and tagging sharks "was not cheap research and, to do it well, it needs to be adequately funded".

Dr Werry was seeking  about $500,000 funding for a white shark-tracking program in Queensland.

"That's the support I'm asking for but that amount is nothing compared to the return for the local economy in terms of protecting beach-goers," he says. "At the end of the day, what is the value of a human life?"