On February 20, 2023, an open water swimmer and diving instructor, Simon Nellist, was killed by a great white shark off Sydney. The 35 year old man had been swimming at Buchan Point, near Little Bay, southeast of Sydney, when the shark attacked him from below.
While training for a charity swim, Nellist was wearing a black wetsuit and swimming alone when the incident took place. Evaluated by the International Shark Attack File and the Australian Shark Incident Database, the event was classified as “Provoked” and “Unprovoked” respectively by the two scientific evaluators.
The International Shark Attack File (ISAF), a global database of all known shark attacks, classified Nellist’s death as a “provoked incident,” which refers to a situation in which a human unintentionally or intentionally initiates contact with a shark. However, The Australian Shark Incident Database, unlike ISAF, has recorded Nellist’s death as an “unprovoked incident.”
The Australian Shark-Incident Database (ASID), formerly known as the Australian Shark Attack File (ASAF), quantifies temporal and spatial patterns of shark-human interactions in Australia. The database has been maintained by Taronga Conservation Society Australia (TCS), since 1984 and includes more than 1,100 individual investigations of shark-bite cases in Australia since 1791. All cases that meet the ‘criteria for inclusion’ are classified as either ‘provoked’ or ‘unprovoked’.
The TCS defines the two categories as follows:
An ‘unprovoked’ encounter between a human and a shark is defined as an incident where a shark is in its natural habitat and has made a determined attempt to bite a human where that person is not engaged in provocative activities.
A ‘provoked’ incident relates to circumstances where the person attracts or initiates physical contact with a shark (accidentally or on purpose) or was fishing for, stabbing, feeding, netting, or handling a shark, or where the shark was attracted to the victim by activities such as fishing, spearfishing (where a fish has already been speared), and cleaning of captured fish. Until 2021, all incidents involving a spearfisher or a commercial diver were categorised (sic) as ‘provoked’. Since review of provocation criteria, incidents involving spearfishers will now be classed as ‘provoked’ only if a fish has already been speared. Incidents involving rays are considered out of scope and are not included in the database.
A strong swimmer and athlete, Nellist had been wearing a black wetsuit while swimming about 150m out from the beach. Dark wetsuits which can make a human resemble shark prey such as seals from below. The nature of the attack, called “ambush predation” is common to white sharks, where the victim is rapidly approached from beneath with a fierce bite of the prey. Nellist was swimming alone when the attack occurred. It has been speculated that unseasonably warm waters have attracted bait fish nearshore, which in turn could seals and sea lions, in turn attracting the shark to nearshore waters. Witness statements attribute the attack to great white shark, estimated to be at least 3m long. It was said to have launched a vertical attack, causing catastrophic injuries. This, and the presence of fishermen nearby lead to the provoked incident designation by the ISAF, albeit an unintentional one.
According to the ISAF, “Unprovoked bites” are defined as incidents in which a bite on a live human occurs in the shark’s natural habitat with no human provocation of the shark. “Provoked bites” occur when a human initiates interaction with a shark in some way. These include instances when divers are bitten after harassing or trying to touch sharks, bites on spearfishers, bites on people attempting to feed sharks, bites occurring while unhooking or removing a shark from a fishing net and so forth.”
The criteria are intended to describe a set of circumstances, and does not infer a victim intentionally attracted a shark attack, such as the case of Nellist. Dr. Gavin Naylor, the director of the Florida Program for Shark Research, and the Florida Museum of Natural History’s ISAF told The Times of London that Nellist was “in no way intending to provoke” the shark but had been swimming in an area where people were fishing. The additional factors of a wetsuit and swimming alone may have led to the provoked determination of the incident.
Fatal shark attacks are extremely rare. In 2022, there were 57 confirmed unprovoked shark killings globally, according to ISAF. Most attacks occurred in the US, and Australia had the second highest number.
The Florida Museum of Natural History’s International Shark Attack File investigated 108 alleged shark-human interactions worldwide in 2022. ISAF confirmed 57 unprovoked shark bites on humans and 32 provoked bites. Around 20 shark attacks are recorded in Australia annually, mainly in New South Wales and Western Australia. Two of these were fatal last year, and seven in 2020.
While it is unusual for sharks to attack humans, Nellist’s death has occurred during a period of increased concern over shark aggression towards fishermen in Australia, The Times noted. The Sydney area is notable for its shark management policy, placing baited drum lines off beaches with the intention to protect swimmers, but with controversial results. Drum lines frequently kill non targeted species such as marine mammals and other sharks, including species that are not aggressive to humans. Without complete shielding of beaches, white sharks have been documented to enter areas where drumlines are set.
After the fatality, Australia’s Department of Primary Industries (DPI) deployed six smart drumlines off the popular swimming and surfing area. Two sharks were captured, both tiger sharks between 1.5- 2 meters, not the white shark estimated at 3 meters (10 feet). Nellist had challenged the effectiveness of drumlines. In August 2022 he posted on his Facebook page that: “Shark nets and drumlines protect no one and kill all kinds of marine life every year. They need to go so these things don’t happen.”
Scientists have hypothesized that sharks can mistake swimmers in wetsuits for seals, their common prey, and an attack is a case of mistaken identity. Swimmers and surfers can reduce their risk of a shark interaction by recreating with a buddy, avoiding areas where shark prey such as seals frequent, signs of wildlife feeding, or spots where attacks have been documented.