![Bullshark Beqa Fiji 2007](https://upload.wikimedia.org/wikipedia/commons/8/8f/Bullshark_Beqa_Fiji_2007.jpg)
There are a range of shark attack prevention techniques employed to reduce the risk of
shark attack
A shark attack is an attack on a human by a shark. Every year, around 80 unprovoked attacks are reported worldwide. Despite their rarity, many people fear shark attacks after occasional serial attacks, such as the Jersey Shore shark attacks of 1 ...
and keep people safe. They include removing sharks by various fishing methods, separating people and sharks, as well as observation, education and various technology-based solutions.
Techniques that involve
culling sharks are contentious. Environmental groups have voiced concern over the impact of reduced shark numbers on ocean ecosystems and the problem of by-catch of other marine life, particularly endangered species.
Because sharks are important to the ecosystem, removing them harms the ecosystem.
Nets
Shark net
The majority of
shark net
A shark net is a submerged section of gillnets placed at beaches designed to intercept large marine animals including sharks, with the aim to reduce the likelihood of shark attacks on swimmers. Shark nets used are gillnets which is a wall of ...
s used are
gillnets
Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...
, which is a wall of netting that hangs in the water and captures the targeted sharks by entanglement. The nets may be as much as long, set at a depth of , have a mesh size of and are designed to catch sharks longer than in length.
Shark nets do not offer complete protection but work on the principle of "fewer sharks, fewer attacks". They reduce occurrence via shark mortality. Shark nets such as those in
New South Wales
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, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
are designed to entangle and capture sharks that pass near them.
Historical shark attack figures suggest that the use of shark nets does markedly reduce the incidence of shark attack when implemented on a regular and consistent basis.
A downside with shark nets is that they do result in
bycatch, including threatened and endangered species.
Between September 2017 and April 2018, 403 animals perished in the nets in
New South Wales
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, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
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, established_title = Before federation
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, including 10 critically endangered
grey nurse shark
The sand tiger shark (''Carcharias taurus''), gray nurse shark, spotted ragged-tooth shark or blue-nurse sand tiger, is a species of shark that inhabits subtropical and temperate waters worldwide. It inhabits the continental shelf, from sandy sho ...
s, 7
dolphin
A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...
s, 7
green turtle
The green sea turtle (''Chelonia mydas''), also known as the green turtle, black (sea) turtle or Pacific green turtle, is a species of large sea turtle of the family Cheloniidae. It is the only species in the genus ''Chelonia''. Its range exten ...
s and 14
great white shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large Lamniformes, mackerel shark which can be found in the coastal surface waters of all the major ocean ...
s.
[http://www.swellnet.com/news/swellnet-dispatch/2018/08/04/sydney-shark-nets-set-stay-despite-drumline-success Swellnet.com. ''Sydney shark nets set to stay despite drumline success.'' Bruce Mackenzie. August 4, 2018. Retrieved September 20, 2018.] However note that
bycatch from shark nets is minor compared to bycatch from commercial fishing
with estimates of 50 million sharks caught unintentionally each year.
Total cost for the shark netting program in
New South Wales
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, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
for the 2009/10 year was approximately , which included the cost of the nets, contractors, observers and shark technicians, shark meshing equipment (dolphin pingers and whale alarms etc.), and compliance audit activities.
For the 51 beaches protected,
this represents a financial cost of approximately per beach per year.
Shark nets have been criticized by environmentalists and conservationists; they say shark nets damage the
marine ecosystem
Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the sur ...
.
[http://www.sealifetrust.org.au/news/latest/shark-nets-australia-work ''Shark nets in Australia – what are they and how do they work?'' Sealifetrust.org.au. Retrieved September 20, 2018.][http://www.sharkangels.org/index.php/media/news/157-shark-nets ''Shark Nets.'' Sharkangels.org. Retrieved September 20, 2018.] The current net program in New South Wales has been described as being "extremely destructive" to marine life; it has also been called "outdated and ineffective".
The New South Wales government prohibits people from rescuing entangled animals — this prohibition has been called "heartless and cruel".
Shark barrier
![Coogee Beach gnangarra-215](https://upload.wikimedia.org/wikipedia/commons/b/b2/Coogee_Beach_gnangarra-215.jpg)
A
shark barrier A shark barrier (otherwise known as a "shark-proof enclosure" or "beach enclosure") is seabed-to-surface protective barrier that is placed around a beach to protect people from shark attacks. Often confused with shark nets, shark barriers form a ful ...
(otherwise known as a "shark-proof enclosure" or "beach enclosure") is seabed-to-surface protective barrier that is placed around a beach to separate people from sharks. Shark barriers form a fully enclosed swimming area that prevents sharks from entering.
Shark barrier design has evolved from rudimentary fencing materials to netted structures held in place with buoys and anchors. Recent designs have used plastics to increase strength and versatility.
When deployed in sheltered areas shark barriers offer complete protection and are seen as a more environmentally friendly option as they largely avoid bycatch. However barriers are not effective on surf beaches because they usually disintegrate in the swell and so are normally constructed only around sheltered areas such as harbour beaches.
A
shark barrier installed at Middleton beach in
Albany, Western Australia
Albany ( ; nys, Kinjarling) is a port city in the Great Southern region in the Australian state of Western Australia, southeast of Perth, the state capital. The city centre is at the northern edge of Princess Royal Harbour, which is a ...
cost to install, with annual maintenance budgeted at per annum.
On
Réunion Island in 2015 two shark proof enclosures cost €2 million to install and €1 million a year to maintain.
[
]
Drum lines
A drum line is an unmanned aquatic trap used to lure and capture large sharks using baited hooks. They are typically deployed near popular swimming beaches with the intention of reducing the number of sharks in the vicinity and therefore the probability of shark attack. Drum lines were first deployed to protect users of the marine environment from sharks in Queensland
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, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, establishe ...
, Australia in 1962. During this time, they were just as successful in reducing the frequency of shark attacks as the shark nets. More recently, drumlines have also been used with great success in Recife
That it may shine on all ( Matthew 5:15)
, image_map = Brazil Pernambuco Recife location map.svg
, mapsize = 250px
, map_caption = Location in the state of Pernambuco
, pushpin_map = Brazil#South A ...
, Brazil where the number of attacks has been shown to have reduced by 97% when the drumlines are deployed.[ While shark nets and drum lines share the same purpose, drum lines are more effective at targeting the three sharks that are considered most dangerous to swimmers: the ]bull shark
The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in ri ...
, tiger shark
The tiger shark (''Galeocerdo cuvier'') is a species of requiem shark and the last extant member of the family Galeocerdonidae. It is a large macropredator, capable of attaining a length over . Populations are found in many tropical and tempera ...
and great white shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large Lamniformes, mackerel shark which can be found in the coastal surface waters of all the major ocean ...
. SMART drumlines can also be utilised to move sharks, which greatly reduces mortality of sharks and bycatch to less than 2%.
In 2014 a three-month trial utilising up to 60 drum lines in Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
cost .
Drum line programmes that involve culling
In biology, culling is the process of segregating organisms from a group according to desired or undesired characteristics. In animal breeding, it is the process of removing or segregating animals from a breeding stock based on a specific tr ...
have been criticized for being environmentally destructive and speciesist
Speciesism () is a term used in philosophy regarding the treatment of individuals of different species. The term has several different definitions within the relevant literature. A common element of most definitions is that speciesism involves t ...
, and have sparked public demonstrations and vocal opposition, particularly from environmentalists, animal welfare advocates and ocean activists. Conservationists say the death of sharks on drum lines harms the marine ecosystem
Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the sur ...
.[Alana Schetzer (8 May 2017). http://pursuit.unimelb.edu.au/articles/sharks-how-a-cull-could-ruin-an-ecosystem ''"Sharks: How a cull could ruin an ecosystem".'' Science Matters. University of Melbourne – via Pursuit. Retrieved September 20, 2018.] The current drum line program in Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, establishe ...
has been called "outdated, cruel and ineffective".[https://www.ntd.tv/2018/09/04/video-endangered-hammerhead-sharks-dead-on-drum-line-in-great-barrier-reef/ ''Endangered Hammerhead Sharks Dead on Drum Line in Great Barrier Reef.'' Jack Phillips. Ntd.tv. Retrieved September 20, 2018.] However environmental damage from drumlines is minor compared to commercial fishing with estimates of 50 million sharks caught unintentionally each year.
Other protection methods
Moving sharks
Moving sharks is a way of reducing shark attacks and reducing shark mortality, by capturing, transporting and releasing the sharks further shore. In Recife, Brazil, sharks that were near shore were captured and physically moved offshore with 70% of potentially aggressive sharks and 78% of other animals caught released alive. Sharks that were moved did not return to the same location. This technique has also been successfully demonstrated in the NSW North Coast SMART drumline trial (Australia) where 99% of targeted sharks and 98% of other animals caught were released alive.
Electronic shark deterrents
Electronic devices create an electromagnetic field to deter shark attack
A shark attack is an attack on a human by a shark. Every year, around 80 unprovoked attacks are reported worldwide. Despite their rarity, many people fear shark attacks after occasional serial attacks, such as the Jersey Shore shark attacks of 1 ...
s and are used by surfers
Surfing is a surface water sport in which an individual, a surfer (or two in tandem surfing), uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suitable ...
, scuba divers, snorkelers, spearfishers, ocean kayak fishers, swimming areas off boats and for ocean fishing. The Ocean Guardian devices are considered one of the few electrical devices on the market that has performed independent trials to determine the effectiveness at deterring shark attacks. Whilst it is noted the Shark Shield Technology does not work in all situations and divers have been attacked whilst wearing Shark Shield, new modelling research from Flinders University states that the proper use of personal electronic deterrents is an effective way to prevent future deaths and injuries. It is estimated that these devices can save up to 1063 Australian lives along the coastline over the next 50 years.
The West Australian government in 2017 announced that they are supporting the Ocean Guardian FREEDOM7 and the Ocean Guardian FREEDOM+ Surf via a $200 subsidiary.
Shark tagging and tracking
Across the world a sample of sharks have been tagged with electronic devices that transmit their location. Acoustic tags transmit pulses which are detected by underwater listening stations when the sharks swim close by, typically within 500 metres. Fin-mounted satellite tags are also commonly used. These tags allow shark movements and behaviour to be monitored and studied and swimmers and surfers can be warned if a shark is detected close to shore.
However a limitation with the system is the tagging will only highlight a very small portion of the dangerous sharks present. It also may lead people into a false sense of security.
Shark spotting
Shark-spotting programs using drone
Drone most commonly refers to:
* Drone (bee), a male bee, from an unfertilized egg
* Unmanned aerial vehicle
* Unmanned surface vehicle, watercraft
* Unmanned underwater vehicle or underwater drone
Drone, drones or The Drones may also refer to:
...
s, fixed-wing aircraft, helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...
s, patrol boat
A patrol boat (also referred to as a patrol craft, patrol ship, or patrol vessel) is a relatively small naval vessel generally designed for coastal defence, border security, or law enforcement. There are many designs for patrol boats, and the ...
s, beach patrol
Beach Patrol is a half-hour television series airing on truTV. The show features lifeguards and police working together to apprehend criminals and save lives.
Each of the program's four seasons have focused on a different city San Diego, Miami ...
s, observation tower
An observation tower is a structure used to view events from a long distance and to create a full 360 degree range of vision to conduct long distance observations. Observation towers are usually at least tall and are made from stone, iron, an ...
s and even blimp
A blimp, or non-rigid airship, is an airship (dirigible) without an internal structural framework or a keel. Unlike semi-rigid and rigid airships (e.g. Zeppelins), blimps rely on the pressure of the lifting gas (usually helium, rather than hy ...
s, are being used and trialled in various locations across the globe. However visibility issues with water clarity can be a problem particularly with aerial patrols, which have been found to identify less than 20% of sharks present. There is also the financial cost of hiring aircraft and/or personnel to conduct the surveillance.
Personal shark repellents
A shark repellent is any method of driving shark
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachi ...
s away from an area and includes magnetic shark repellent
Magnetic shark repellents utilize permanent magnets, which exploit the sensitivity of the Ampullae of Lorenzini in sharks and rays (electrosense). This organ is not found on bony fish (teleosts), therefore, this type of shark repellent is selectiv ...
, electropositive shark repellent Electropositive metals (EPMs) are a new class of shark repellent materials that produce a measurable voltage when immersed in an electrolyte such as seawater. The voltages produced are as high as 1.75 VDC in seawater. It is hypothesized that this vo ...
s, electrical repellents (including Shark Shield) and semiochemical
A semiochemical, from the Greek wiktionary:σημεῖον, σημεῖον (''semeion''), meaning "signal", is a chemical substance or mixture released by an organism that affects the behaviors of other individuals. Semiochemical communication c ...
s. One example is a product called Anti-Shark 100 which is an aerosol can that contains an extract of dead shark tissue. There is a range of evidence that supports the effectiveness of this product. Chemical repellents have been researched since before the 1940s, some of which have raised concerns as to their effectiveness. The semiochemical used in the Anti-shark 100 product have been independently tested & verified on Caribbean reef sharks, however there are concerns it may attract Tiger and White sharks.
Other examples of personal shark protection technologies include wearing interruption patterned or camouflage wetsuits, magnetic repellents incorporating a small magnet in a band worn on the wrist or ankle, acoustic repellents that mimic the sound of orcas
The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pat ...
and changing surf board colours. However, either the products associated with these technologies have not been independently tested, or independent tests highlighted that they did not work.
In 2018 independent tests were carried out on five Shark Repellent technologies using Great white shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large Lamniformes, mackerel shark which can be found in the coastal surface waters of all the major ocean ...
s. Only Shark Shield’s ''Ocean Guardian Freedom+ Surf'' showed measureable results, with encounters reduced from 96% to 40%. Rpela (electrical repellent technology), SharkBanz bracelet & SharkBanz surf leash (magnetic shark repellent
Magnetic shark repellents utilize permanent magnets, which exploit the sensitivity of the Ampullae of Lorenzini in sharks and rays (electrosense). This organ is not found on bony fish (teleosts), therefore, this type of shark repellent is selectiv ...
technology) and Chillax Wax (semiochemical
A semiochemical, from the Greek wiktionary:σημεῖον, σημεῖον (''semeion''), meaning "signal", is a chemical substance or mixture released by an organism that affects the behaviors of other individuals. Semiochemical communication c ...
) showed no measureable effect on reducing shark attacks.
Protection by dolphins
There are documented instances of bottlenose dolphins protecting humans from shark attacks, one off the coast of New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
in 2004 and one attack on a surfer in northern California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
in August 2007. There is no accepted explanation for this behavior; as mentioned in the ''Journal of Zoology'', "The importance of interactions between sharks and cetaceans has been a subject of much conjecture, but few studies have addressed these interactions". In some cases, sharks have been seen attacking, or trying to attack dolphins. The presence of porpoises does not indicate the absence of sharks as both eat the same food and surfers have been attacked by sharks whilst in the presence of dolphins.
Shark sonar
In September 2015, a shark sonar created by Ric Richardson was tested in Byron Bay
Byron Bay (Minjungbal: ''Cavvanbah)'' is a beachside town located in the far-northeastern corner of the state of New South Wales, Australia on Bundjalung Country. It is located north of Sydney and south of Brisbane. Cape Byron, a headla ...
, Australia. It is a passive sonar device that does not interfere with animals like dolphins. The final device will sit on the ocean floor and claimed to detect sharks over 2,5 meters long when they are 100 meters away. An alarm will notify people that they have to go out of the water. Other shark sonar systems have been tested, however results have concluded that the shark sonar systems are not effective.
By country
Australia
Queensland and New South Wales
In Queensland and NSW systematic long term shark control programs using shark nets and drumlines are utilised to reduce the risk of shark attack. Since 1936 sharks nets have been utilised off Sydney beaches. Nowadays they are employed on both NSW and Queensland beaches; 83 beaches are meshed in Queensland compared with NSW's current 51.
The technique of setting drum lines is also used in Queensland and New South Wales, where they have been used in association with shark nets. Before 1962, there were 82 recorded attacks. Since the policy was implemented there has only been one recorded death, at Amity Point in January 2006. 21-year-old Sarah Kate Whiley was attacked by as many as three sharks in Rainbow Channel. The attack occurred in an unpatrolled area. Queensland Fisheries Minister John McVeigh has described the longevity of the netting and drum line program as being "a good indicator that it had the support of most Queenslanders".
The baited drum lines attract sharks from within a 3–5 km radius, preventing sharks from reaching swimming areas. They also capture less bycatch than shark nets.[
There were a total of 97 fatalities attributed to shark attacks in Queensland between 1858 and 2014. In New South Wales there were a total of 96 fatalities attributed to shark attack between 1771 and 2014.
The current shark mitigation programs in Queensland and New South Wales have been called culls, and have been criticized by environmentalists, who say removing sharks harms the marine ecosystem.] Between 1950 and 2008, 577 great white sharks and 352 tiger sharks died in the nets in New South Wales — also during this period, 15,135 marine animals were caught and died in the nets, including whales, turtles, rays, dolphins, and dugongs.[https://web.archive.org/web/20181002102324/https://www.marineconservation.org.au/pages/shark-culling.html Marineconservation.org.au. Shark culling (archived). Retrieved November 30, 2018.] In Queensland, from 2001 to 2018, a total of 10,480 sharks died on drum lines.
= NSW North Coast shark net and smart drumline trial
=
Following 11 shark attacks along the NSW north coast between 2014 and 2016, including two fatalities, Shark nets
A shark net is a submerged section of gillnets placed at beaches designed to intercept large marine animals including sharks, with the aim to reduce the likelihood of shark attacks on swimmers. Shark nets used are gillnets which is a wall of ne ...
and SMART drumlines were deployed in December 2016 to cover five additional beaches along the NSW North Coast in a two-year trial. Five nets were deployed off Seven Mile Beach off Lennox Head; Sharpes, Shelly and Lighthouse beaches off Ballina; and Main Beach at Evans Head. Twenty five drumlines were also deployed among nets at Ballina and Evans Head beaches (15 off Ballina; 10 off Evans Head). The trial was successful with no shark attacks occurring at the protected beaches. The SMART drumline caught 230 targeted sharks with 99% of targeted sharks and 98% of other animals caught were released alive. The SMART drumlines are now being expanded to other NSW regions. The shark net trial caught 11 targeted sharks and had a 54% survival rate for all animals caught and will not be continued.
Western Australia
In August 2018 following continual shark attacks and public pressure the West Australian state government announced a trial of "smart" drumlines along Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
's South West coast, near Gracetown. On the 12 May 2021 the trial ended after only two white sharks were captured and it was concluded the trial did not reduce the risk of shark attack.
Western Australia also deploys shark enclosures in a range of locations as well as aerial shark spotters, beach patrols, shark tagging efforts and associated tracking and notification systems.
There were a total of 114 unprovoked shark attacks in West Australia between 1870 and 2016, including 16 fatalities since 2000.
South Australia
In South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
, spotter planes and a small number of patrolled swimming beaches are the only methods used to mitigate the risk of shark attack. On 6 February 2014, Port Lincoln tuna " baron" Hagen Stehr
Dr Hagen Heinz Stehr AO (born 1941) is a German-born multi-millionaire businessman, tuna fisherman and founder of the Stehr Group.
Career
Stehr lives in Port Lincoln, South Australia where he manages his business interests in fishing and aquac ...
expressed his support for the Western Australian shark cull
The Western Australian shark cull is the common term for a former state government policy of capturing and killing large sharks ( shark culling) in the vicinity of swimming beaches by use of baited drum lines. The policy was implemented in 20 ...
. He also stated that his business' spotter planes had observed increases in great white shark numbers off the west coast of Eyre Peninsula
The Eyre Peninsula is a triangular peninsula in South Australia. It is bounded by the Spencer Gulf on the east, the Great Australian Bight on the west, and the Gawler Ranges to the north.
Originally called Eyre’s Peninsula, it was named af ...
. He acknowledged that his tuna farming operations attract some sharks. He told '' The Advertiser'' that he believed "selected culling of sharks is a must. It is crazy stuff to put them under protection so it becomes a major offence to kill them." Critics of Stehr's stance note that a cull of sharks in SA would be beneficial to his business, as tuna is a major source of food for sharks. Shark attack survivor turned conservationist Rodney Fox
Rodney Winston Fox (born 9 November 1940) is an Australian film maker, conservationist, survivor of an attack by a great white shark, and one of the world's foremost authorities on that species. He was inducted into the International Scuba D ...
has spoken out against the cull, saying "When a shark attacks someone, we go 'the shark needs to be punished'. They don't live under our laws. It's a different world down there and it should be treated differently."
At September 2014, there had been a total of 82 shark attacks in South Australia
As of 2014, there have been 82 recorded shark attacks in South Australia since the establishment of the colony in 1836. 20 of those have involved a single fatality. Victims were involved in a range of aquatic activities, including surfing, divin ...
since 1836, including 20 fatalities.
South Africa
In KwaZulu-Natal, South Africa a long term shark control program utilising a combination of shark nets and drum lines are used to mitigate the risk of shark attack. The region's shark attack statistics primarily reflect the effectiveness of netting, as drum lines were only introduced recently, following their successful use for over 40 years in Queensland, Australia. The KwaZulu-Natal Sharks Board
A notice at a beach protected by the Board
The KwaZulu-Natal Sharks Board (KZNSB), previously the Natal Sharks Board and Natal Anti-Shark Measures Board is an organisation that maintains a "shark control" program (using shark nets and drum lines ...
(KZNSB) says "Both types of equipment function by reducing shark numbers in the vicinity of protected beaches, thereby lowering the probability of encounters between sharks and people at those beaches." The KZNSB says, "At Durban
Durban ( ) ( zu, eThekwini, from meaning 'the port' also called zu, eZibubulungwini for the mountain range that terminates in the area), nicknamed ''Durbs'',Ishani ChettyCity nicknames in SA and across the worldArticle on ''news24.com'' from ...
, from 1943 until the installation of shark nets in 1952, there were seven fatal attacks. Since the installation of nets there have been no fatalities at Durban and no incidents resulting in serious injury." The KZNSB also says, "At KwaZulu-Natal's other ettedbeaches, from 1940 until most of those beaches were first netted in the 1960s, there were 16 fatal attacks and 11 resulting in serious injury. In the three decades since nets were installed, there have been no fatal attacks at those beaches and only four resulting in serious injury." The presence of nets has greatly reduced the number of shark attacks along Natal beaches. It is unclear whether more sharks caught on drum lines survive when compared to shark net captures in KwaZulu-Natal, but the lines have shown reduced non-target species bycatch. Drum lines set in the region are baited with 500 grams of meat per hook and are believed to only attract sharks from several hundred metres away.
Seasonal and temporary bathing bans and "discretionary bathing" are additional strategies employed in the region. Bans often follow net displacement or damage due to storms or swell, or net removal due to whale stranding. Nets are also removed during the annual sardine run
The KwaZulu-Natal sardine run of southern Africa occurs from May through July when billions of sardines – or more specifically the Southern African pilchard ''Sardinops sagax'' – spawn in the cool waters of the Agulhas Bank and move northwar ...
to limit the degree of bycatch during the event. Pressure from the tourism industry to reinstate nets during the sardine run has previously proven "disastrous", resulting in large numbers of shark and dolphin mortalities.
The "shark control" program in KwaZulu-Natal has been called "archaic" and "disastrous to the ecosystem" (by environmentalists). In a 30-year period, more than 33,000 sharks have died in KwaZulu-Natal's shark mitigation program — also during this period, 2,211 turtles, 8,448 rays, and 2,310 dolphins died. Environmental groups say KwaZulu-Natal's "shark control" program is unethical and harms the marine ecosystem. Activists in Durban say that Durban's shark nets serve no purpose.
United States
In Hawaii
Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...
, seven short term shark culls utilising long-lines took place between 1959 and 1976. During this time, 4,668 sharks were caught, at a cost of US$300,000. Although the Hawaiian resident and tourist human population increased dramatically, the number of shark attacks remained constant (in contrast to Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
, where the number of shark attacks has increased in line with human population increases) and the short term programs were not considered a success by the authors of a shark culling study. The study concluded that the culls "do not appear to have had measurable effects on the rate of shark attacks in Hawaiian waters".
The publication came at a time during intense community debate over culling in Hawaii, documented by local journalist Jim Borg in his 1993 book, ''Tigers of the Sea, Hawaii’s Deadly Tiger Sharks''. Borg detailed the debates between the study's authors and other scientists who argued that the experiences of South Africa's KwaZulu-Natal Shark Board demonstrated the effectiveness of the culling. The debate began with the November 1991 shark attack which resulted in the death of Martha Morrell off Maui and embroiled the subsequently formed Hawaii Shark Task Force, Borg writes.
Statistics from 2013 showed the number of shark attacks in Hawaii was spiking.
Brazil
Drumlines and long lines have been used successfully in Recife
That it may shine on all ( Matthew 5:15)
, image_map = Brazil Pernambuco Recife location map.svg
, mapsize = 250px
, map_caption = Location in the state of Pernambuco
, pushpin_map = Brazil#South A ...
in a long term program, where shark attacks have been reduced by around 97%. Sharks are initially caught on baited drum lines. Once captured, the sharks (if found alive) are humanely handled and tagged. They are then relocated offshore and their movements are tracked. The project is known as the Shark Monitoring Program of Recife (SMPR). A report assessing the program's performance was published in 2013. It stated: "Overall, the SMPR seems to be less detrimental than shark meshing strategies while clearly contributing for enhancing bather safety; thus, it may provide an effective, ecologically balanced tool for assisting in shark attack mitigation."[
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Réunion Island (France)
The prevalence of shark attacks at Réunion Island—there were 19 attacks between 2011 and 2016, including seven which were fatal—prompted Réunion island's government to carry out a range of systematic long term shark protection activities, including a shark cull, utilising "smart" drumlines and longlines. In the five years to August 2016, more than 170 sharks died as part of the cull.
In 2015, two shark-proof fences were strung at beaches to the west of the island, at a cost of €2 million. Maintenance of the fences is projected to cost €1 million a year. The protective nets / shark enclosures at the two beaches have a total length of just under 1 mile and are subject to damage from heavy swell. On 27 August 2016 a surfer lost an arm and a foot from a shark attack while surfing within one of the enclosures. It was reported that at the time of the attack there was a two-meter hole in the nets, most probably caused by the swell.
References
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Safety practices