All manner of anti-shark devices claim to keep the apex predator away from humans, yet several marine ecologists say some hammerheads need protection from us.
Scalloped hammerhead sharks (Sphyrna lewini), named for the notches along their distinct head, are critically endangered. Despite their ongoing global decline, we don't know much about them.
But in recent years, schools of the marine creatures have been showing up more often, and in large numbers, on Queensland's Gold Coast and on the west coast near Perth.
The enigmatic species has been caught by anglers and mobbed by divers with video cameras, prompting suggestions from researchers for marine sanctuary zones and human interaction codes of conduct.
Over March and April more than 100 young hammerheads, ranging from 30-centimetre-long pups to more mature individuals measuring about 1 metre, started schooling in the shallows off Burleigh Heads.
Griffith University marine ecologist Olaf Meynecke said it was the second year in a row that the species was seen foraging at Burleigh.
"Last year they were all around the 1-metre mark," he said.
"But this year, it's definitely not the case. There's big ones and little ones."
The return of the sharks in different sizes, including pups maybe no more than a week old, suggested they had come to the site for shelter or food, Dr Meynecke added.
Young scalloped hammerheads are prey for larger adults of different shark species, so, for protection, they school in great aggregations which can number in their hundreds.
They pup in estuarine waters in Australia for several years before moving out to deeper areas and waters in other parts of the Indo-Pacific.
But the Burleigh gatherings are in a readily accessible place for humans, and can attract swimmers, with camera in hand, who chase baby sharks.
Shark ecologist Johan Gustafson said if you tried to catch and handle a young hammerhead, you could both get hurt.
"If they're handled incorrectly, they overstress like a greyhound," he said.
"They can't relax, they can't clear all their gases, so they tend to die."
If the sharks were chased out of the protection of a bay into deeper water, they risked being eaten by whalers and bull sharks, Dr Gustafson added.
And although anglers are not allowed to keep the species if they catch it in Queensland, scalloped hammerheads will, more often than not, die even after being released.
Should the sharks continue to gather at particular sites, Dr Meynecke said measures such as seasonal recreational fishing bans in areas like Burleigh needed to be considered.
"If we do see an endangered species aggregate over several weeks in an area over consecutive years, there needs to be a combination of fishing rules in this area and public education," he said.
So do we need new rules?
One suggestion is to develop a human interaction code of conduct, similar to what already exists for dolphins, whales and whale sharks.
Under such codes, minimal approach distances are recommended for both vessels and swimmers, such as the national rule that boats must not approach closer than 100m to a whale.
University of Western Australia marine ecologist Naima Andrea López is one scientist calling for a scalloped hammerhead code of conduct and sanctuary zones where aggregations regularly visit.
Over the past five years, she has captured drone footage of the southernmost-recorded congregation of scalloped hammerheads off Shoalwater, an outer coastal suburb of Perth.
"These endangered animals might be spending more time around the busy waters of Perth than we thought," Dr López said.
"Scalloped hammerheads are not dangerous to humans, but this is worrying because it might increase their risk to interact with fishers, and also to be disturbed by boats and divers while resting.
"By putting a sanctuary zone in place, a large number of individuals would be protected whilst present at a place where they recurrently and predictably use."
Dr López said conversations with local people during her recent summer of drone surveys at Shoalwater were positive towards protecting the aggregation.
"It was incredibly inspiring to experience first-hand the willingness of the community to see conservation actions and the creation of a code of conduct taking place at the Shoalwater Islands Marine Park," she said.
Dr Meynecke thought any code should go further and cover all interactions with marine megafauna.
"Social media has caused a false perception and generated dangerous intrusion into the space of marine life," he said.
UWA Marine Futures director Jessica Meeuwig spoke with ministers in the WA government about the potential for a scalloped hammerhead code of conduct in 2022.
But the office of the state's environment minister gave no update to the ABC when asked as to whether such a measure would be pursued.
Similarly, the minister's office provided no comment for its position on an additional no-fishing sanctuary zone in Shoalwater.
A spokesperson for the federal Department of Climate Change, Energy, the Environment and Water said it had no plans to develop a code of conduct for the scalloped hammerhead.
"Public interactions are not one of the key threats identified for the scalloped hammerhead shark," they said.
Commercial fishing is identified as the biggest global threat to the species.
Protecting hammerheads on a larger scale
Much of the existing conservation management of the scalloped hammerhead comes down to state fishing plans.
WA has banned on-shore shark fishing from Perth beaches. A shark fishery, which covered much of the scalloped hammerhead distribution in the state, has not operated for decades.
Queensland banned commercial fishing of hammerheads from January 1, and phased out gillnets around the Great Barrier Reef area, in which scalloped hammerheads have been caught.
What is difficult to determine, however, is the current health of Australian populations of the shark, which could be impacted by fishing in other countries such as Indonesia.
There was an estimated 50 to 80 per cent decline of scalloped hammerheads in Australia between 1950 and 2021.
Dr Gustafson hopes to better inform Queensland marine managers with data about habitats used by the species and when to formulate protection plans at sites used by the sharks.
He is working on a project tracking hammerhead movements with the University of Sunshine Coast.
"The work we're doing on the juvenile stage of these hammerheads is: where are they? What do they utilise in those areas? Is it mud? Is it seagrass areas, coral?" Dr Gustafson said.
"That's things we need to know to enforce protection measures."
Dr López is looking to do similar work by tagging scalloped hammerheads at Shoalwater.
"We need to know what is changing [with where sharks go] in order to implement best conservation practices," she said.
"By continuing the monitoring of the hammerheads, we can learn where and when these endangered animals are around Perth's coast, and inform management."
The big unknown is what climate change is doing to the populations of this mysterious species.
Dr Meynecke hypothesised that, as the oceans warm, it was possible places like Burleigh had become important sites for food or shelter for the species.
"It kind of shows how important it is, in particular with climate change, to ensure we have places ... that these animals can use when they need them," he said.
"Marine species are forced to adapt quickly. They will need to enter new habitats, and sometimes even places that we already heavily occupy, such as a Gold Coast beach."