Ocean Guardian (Shark Shield)

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Ocean Guardian Holdings Limited
SeaChange Technology (Shark Shield)
Public Private
IndustryTechnology, Shark Deterrents, Consumer Electronics
HeadquartersWarriewood, NSW, Australia,
Area served
Key people
Lindsay Lyon (CEO)
ProductsElectrical shark deterrents

Ocean Guardian is the manufacturer of devices that use Shark Shield Technology. The electrical wave-form used in the Shark Shield Technology is based on a technology originally invented by the KwaZulu-Natal Sharks Board of South Africa in the 1990s.

Shark Shield is a personal electronic device that creates an electromagnetic field to deter shark attacks and is used by surfers, scuba divers, spearfishing, and ocean kayak fishing. It has been considered one of the few electrical devices on the market that has performed independent trials to determine the effectiveness [1][2] at deterring shark attacks.[3] However note that the Shark Shield does not work in all situations[1][4][2] and divers have been attacked whilst wearing Shark Shield.[3][5]


The original wave-form used in the shark repelling technology was devised by three inventors, Graeme Charter, Sherman Ripley, and Norman Starkey, and released in 1995 by POD Holdings Ltd, a joint venture company partly owned by the Natal Sharks Board and the South African government.[6]

In the late 1990s the KwaZulu-Natal Sharks Board developed the first electrical shark deterrent, the SharkPOD (protective oceanic device or simply POD).[6] In 2001, the KwaZulu-Natal Sharks Board ceased distribution of the SharkPOD. All rights to the intellectual property were licensed to a South Australian-based company, SeaChange Technology Holdings, which developed various new application patents resulting in a commercial product line under the brand name Shark Shield in April 2002.[7]

In 2007, Shark Shield introduced the third generation of products to replace the original FREEDOM4 and DIVE01, expanding the range of products offered to include the SCUBA7 (replaced the DIVE01) and introducing two new designs: the FREEDOM7 (replaced the FREEDOM4), a versatile option that can be used by a broad range of ocean-users, including scuba divers, spearfishers, boaters, and kayakers;[8] and the SURF7, designed to be fitted onto a surfboard or stand-up paddleboard to offer surfers protection from sharks.[9]

The Shark Shield Technology was further developed by the Australian company SeaChange Technology Holdings Pty Ltd, and commercialized by its trading company Shark Shield Pty Ltd established in October 2006.[7][10] SeaChange Technology Holdings Pty Ltd changed its name to Ocean Guardian Holdings Limited in 2018 with Shark Shield Pty Ltd trading as Ocean Guardian.[11]

In 2016, with research and development funding from the Western Australian government, Ocean Guardian announced the FREEDOM+ Surf a product designed in partnership with two times World Champion surfer Tom Carroll specifically designed for surfers.[12]

The new design removed the trailing antenna of the older SURF7 being replaced with a sticker-thin antenna on the underside of the surfboard, with the fully transferable power module located in the kicker of the tail pad.[13][14]

In January 2019 the company announced the world's first handheld electrical shark deterrent based on Shark Shield Technology called the eSPEAR. The eSPEAR is designed primarily for spearfishermen, divers and snorkelers.[15] The Ocean Guardian product line was further expanded to include the BOAT01 to create a safe swimming area around vessels, and the FISH01 to assist ocean fishermen land their catch without being taken by sharks.[16]

On May 26, 2017 the Western Australian government implemented a $200 consumer rebate for scientifically proven electrical shark deterrents. The Ocean Guardian FREEDOM7 and FREEDOM+ Surf are the only products approved.[17][18]

In addition to traditional ocean sports, Ocean Guardian products are in use with various government bodies including police and navies, and were used by production members in the filming of both The Shallows and USS Indianapolis: Men of Courage.[19][20] Long-distance swimmer, Diana Nyad, in her record-breaking swim crossing from Cuba to Florida without a cage, was completed with help from Shark Shield.[21]


All chondrichthyans have highly sensitive electrical receptors called the "ampullae of Lorenzini" located in their snouts. These tiny gel-filled sacs sense electric current from prey at very close distances, typically less than one meter. The jelly is highly conductive and allows the electrical potential at the opening of the pore to be transferred to the ampulla.[22] They use these short-range sensors when feeding or searching for food. They do not use electrical receptors to track animate objects over long distances; other senses such as audition and olfaction are the primary drivers.[23][24]

Ocean Guardian devices create an electrical field that creates an unpleasant sensation impacting the shark's ampullae of Lorenzini. This effect may not be entirely reliable, with divers reportedly having sustained attacks while wearing the devices.[25] When the shark comes into the range of the field, it experiences uncontrollable muscular spasms, causing it to flee the area.[26]

The field is projected from two electrodes, which create an elliptical field that surrounds the user. Both electrodes must be immersed in the water for the field to be created. Research conducted by the South African National Space Agency in 2012 estimated the Shark Shield electrical field to be about 4–5 m in diameter.[27]

While sharks are attracted to electromagnetic pulses produced by potential prey animals, the electronic field emitted by the Shark Shield does not attract sharks to the device, so would not increase the risk of attracting sharks to the vicinity of the user.[28] A shark's sensory organs are acutely sensitive to low-voltage gradients (> 5 nVcm), enabling them to detect very low-frequency electronic fields between 1 and 8 Hz at short range, after which the other senses (sight, chemoreception, and mechanoreception) aid the shark in capturing its prey.[23][24] The range at which an electronic shark deterrent emits a field that is the equivalent of a prey-like stimulus (about 1–100 nV/cm) is much further than their short-range detection facilitates. Should a shark approach the device, the strength of the electric field gets stronger the closer it gets, and soon causes the shark extreme discomfort, forcing it to turn away.[29] Scientific studies modelling this effect show that the output produced at a 3-m distance is far greater than that produced by prey, and drops off significantly beyond a 6-m radius, where it is beyond the short-range detection ability of a shark.[27]

Testing and research[edit]

The original "SharkPOD" was tested for eight years off Dyer Island with mainly great white sharks, and was the first electronic device that was proven successful in deterring sharks when tested by Ron Taylor and Valerie Taylor in 1997 against great white sharks, tiger sharks, hammerhead sharks, and other shark species in Australia and South Africa with positive results; they made a documentary about it called "Shark POD".[30]

In 2003, C F Smit, Department of Statistics, University of Pretoria, South Africa and V Peddemors, Department of Zoology, University of Durban-Westville, South Africa (Peddemors was employed by the Natal Sharks Board at the time) researched "Estimating the Probability of a Shark Attack when using an Electric Repellent". In two series of tests of the SharkPOD, data were collected on the time needed to attack the bait, under power-off and power-on (active) conditions. Conclusions were separately drawn after completion of the first experiment (in which 8 attacks were successful in 98 five-minute active periods), and after completion of the second experiment (in which no successful attacks were recorded in 24 ten-minute active periods). In general, the probability of an attack in at most 5 minutes was reduced from about 0.70 in power-off mode to about 0.08 in power-on mode and in a period of at most 10 minutes from 0.90 to 0.16.[31]

In 2010, SafeWork South Australia, the government agency responsible for administering occupational health, safety, and welfare laws in South Australia, commissioned the South Australian Research and Development Institute to conduct a study into the effectiveness of the Shark Shield FREEDOM7 product.[32] The research team conducted field experiments testing white shark response to both a static bait (natural prey) and a dynamically towed seal decoy at Neptune Islands, South Australia, and Seal Island, South Africa, respectively, documenting their findings in a research report titled: "Effects of the Shark Shield electric deterrent on the behaviour of white sharks (Carcharodon carcharias)". A total of 116 trials using a static bait were undertaken at the Neptune Islands, South Australia, and 189 tows were conducted using a seal decoy near Seal Island, South Africa.[33] The proportion of baits taken during static bait trials was not affected by the deterrent. The deterrent increased the time it took to take a static bait, and the number of interactions per approach. The effect of the Shark ShieldTM was not uniform across all sharks. The number of interactions within 2 m of the deterrent decreased when it was activated. No breaches and only two surface interactions were observed during the dynamic seal decoy tows when the deterrent was activated, compared to 16 breaches and 27 surface interactions when the deterrent was not activated. Although the fine-scale positioning and presence/absence data collected to assess the potential of the device to attract white sharks was limited to one trip, our results did not suggest that sharks were attracted to the deterrent. The deterrent had an effect on the behaviour of white sharks, but did not deter or repel them in all situations.

In July 2016, shark researchers from the Neuroecology Group at the University of Western Australia had published a study into the effectiveness of the Shark Shield shark deterrent on PLOS ONE "How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour". The research team was funded by the Western Australian government and included UWA Oceans Institute Director Professor Shaun Collin, Associate Professor Nathan Hart and Dr Ryan Kempster. Using a modified stereo-camera system, the research quantified behavioral interactions between white sharks (Carcharodon carcharias) and a baited target in the presence of a commercially available, personal electric shark deterrent (Shark Shield Freedom7). The stereo-camera system enabled an assessment of the behavioral responses of C.carcharias when encountering a non-lethal electric field many times stronger than what they would naturally experience. Upon their first observed encounter, all C. carcharias were repelled at a mean (± std. error) proximity of 131 (± 10.3) cm, which corresponded to a mean voltage gradient of 9.7 (± 0.9) V/m. With each subsequent encounter, their proximity decreased by an average of 11.6 cm, which corresponded to an increase in tolerance to the electric field by an average of 2.6 (± 0.5) V/m per encounter. Despite the increase in tolerance, sharks continued to be deterred from interacting for the duration of each trial in the presence of an active Shark Shield. Furthermore, the findings provide no support to the theory that electric deterrents attract sharks. The results of this study provide quantitative evidence of the effectiveness of a non-lethal electric shark deterrent, its influence on the behaviour of C.carcharias, and an accurate method for testing other shark deterrent technologies.[34][35]

In reviewing the 2016 University of Western Australia[36] research, the Australian Geographic magazine published an article titled “Great White Shark Deterrent almost 100 Per Cent Effective”.[37]

In 2016, in a study conducted by the Australian consumer advocacy group, Choice magazine found that Ocean Guardian (Shark Shield) was the only independently tested shark repellent to be effective.[38]

In 2018 the New South Wales state government funded research conducted by Flinders University to test the Effectiveness of five personal shark deterrents for surfers. Flinders tested five personal shark deterrents developed for surfers Ocean Guardian FREEDOM+ Surf, Rpela, SharkBanz bracelet, SharkBanz surf leash, and Chillax Wax) by comparing the percentage of baits taken, distance to the bait, number of passes, and whether a shark reaction could be observed. A total of 297 successful trials at the Neptune Islands Group Marine Park in South Australia, during which 44 different white sharks (Carcharodon carcharias) interacted with the bait, making a total of 1413 passes. The effectiveness of the deterrents was variable, with the FREEDOM+ Surf affecting shark behaviour the most and reducing the percentage of bait taken from 96% (relative to the control board) to 40%. The mean distance of sharks to the board increased from 1.6 ± 0.1 m (control board) to 2.6 ± 0.1 m when the FREEDOM Surf+ was active. The other deterrents had limited or no measureable effect on white shark behaviour. Based on the power analyses, the smallest effect size that could be reliably detected was ∼15%, which for the first time provides information about the effect size that a deterrent study can reliably detect.[39][40]

Further reading[edit]

  • C F Smit; Victor Peddemors (2003). "Estimating the Probability of a Shark Attack when using an Electric Repellent". South African Statistical Journal.
  • Charlie Huveneers; Paul J. Rogers; Jayson M. Semmens; Crystal Beckmann; Alison A. Kock; Brad Page; Simon D. Goldsworthy (2012). "Effects of the Shark Shield electric deterrent on the behaviour of white sharks (Carcharodon carcharias)". South Australian Research and Development Institute (SARDI).
  • Ryan M. Kempster; Channing A. Egeberg; Nathan S. Hart; Laura Ryan; Lucille Chapuis; Caroline C. Kerr; Carl Schmidt; Charlie Huveneers; Enrico Gennari; Kara E. Yopak; Jessica J. Meeuwig; Shaun P. Collin (2016). "How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour". The Oceans Institute and the School of Animal Biology, The University of Western Australia.
  • Charlie Huveneers; Sasha Whitmarsh; Madeline Thiele; Lauren Meyer; Andrew Fox; Corey J.A. Bradshaw (2018). "Effectiveness of five personal shark-bite deterrents for surfers". Southern Shark Ecology Group, College of Science and Engineering, Flinders University, Adelaide, Australia. Fox Shark Research Foundation, Adelaide, South Australia, Australia. Global Ecology, College of Science and Engineering, Flinders University, Adelaide, Australia.

See also[edit]


  1. ^ a b Kempster RM, Egeberg CA, Hart NS, Ryan L, Chapuis L, Kerr CC, et al. (1 June 2016). "How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour". PLoS ONE. 11 (7): e0157717. doi:10.1371/journal.pone.0157717. PMC 4930202. PMID 27368059.
  2. ^ a b Huveneers, C. (June 2012), Effects of the Shark Shield electric deterrent on the behaviour of white sharks Carcharodon carcharias (PDF), Australia: SARDI, retrieved 3 February 2014
  3. ^ a b "Do shark repellents work?". Choice. Retrieved 5 December 2019.
  4. ^ Williamson, Brett (20 June 2012). "SA researchers trial effectiveness of electronic shark deterrent devices on Great Whites". ABC News. Retrieved 1 June 2017.
  5. ^ "Clarkson was wearing shark shield". Port Lincoln Times. 3 July 2013. Retrieved 2 June 2017.
  6. ^ a b Control of Sharks. "Patent US5566643 A". Google Patents. Retrieved 25 September 2013.
  7. ^ a b Kwa-Zulu Natal Sharks Board. "Electrical Shark Repellent". Archived from the original on 28 September 2013. Retrieved 25 September 2013.
  8. ^ Ingrid Loos Miller (2010). Fearless Swimming for Triathletes: Improve Your Open Water Skills. 79: Meyer & Meyer Verlag. p. 166. ISBN 1841261203.
  9. ^ John Liang (20 November 2014). "Shark Shield To Introduce Re-Designed, Modular Product In 2015". Retrieved 18 May 2016.
  10. ^ Paul S. Auerbach (2011). Wilderness Medicine: Expert Consult Premium Edition - Enhanced Online Features. Elsevier Health Sciences. p. 23004. ISBN 1455733563.
  11. ^ "Shark Shield rebrands to Ocean Guardian and appoints Banjo as its new creative agency". Campaign Brief. Retrieved 22 March 2018.
  12. ^ "$967,000 awarded to shark mitigation research". Department of Primary Industries and Regional Development.
  13. ^ "Risque requin: La préfecture appelle à la prudence".
  14. ^ "Shark Shield : un nouveau modèle adapté au Surf".
  15. ^ "eSPEAR – World's First Handheld Shark Deterrent". Indiegogo.
  16. ^ "The new addition to enjoying swimming off your boat!". Powerboat World.com. Retrieved 22 September 2018.
  17. ^ "More than 3,000 Western Australian surfers and divers boost their personal protection". Mirage News. Retrieved January 9, 2019.
  18. ^ "Staying Safe - Shark Deterrent Rebate". Sharksmart.
  19. ^ Ceridwen Dovey (26 April 2016). "Sharing the Sea with Sharks". Newyorker.com.
  20. ^ "Navy approves Shark Shield after attack". The Sydney Morning Herald. 6 May 2010.
  21. ^ Elizabeth Armstrong Moore (8 August 2011). "Historic 103-mile swim aided by electric shark shield". CNET.
  22. ^ Benedict King, John Long. "How sharks and other animals evolved electroreception to find their prey". Phys Org. Retrieved 13 February 2018.
  23. ^ a b Collin, SP (2010). "Electroreception in Vertebrates and Invertebrates". Encyclopedia of Animal Behavior. 1: 611–620.
  24. ^ a b Kempster, RM; McCarthy ID; Collin SP. (2012). "Phylogenetic and ecological factors influencing the number and distribution of electroreceptors in elasmobranchs". Journal of Fish Biology. 80: 2055–2088. doi:10.1111/j.1095-8649.2011.03214.x.
  25. ^ "Dive deep into one of the world's most dangerous jobs on 'Abalone Wars'". Philippine Star. 9 January 2013. Archived from the original on 7 August 2016. Retrieved 18 May 2016.
  26. ^ Ryan Kempster, Shaun Collin. "Independent Study Proves That This Shark-Repelling Device Really Does Work". Science Alert. Retrieved 8 July 2016.
  27. ^ a b South African National Space Agency (2012). "Interim report on measurement and analysis of the electric fields produced by the SharkPOD and Shark Shield". Doc No: 6035-0006-722-A1. Cite journal requires |journal= (help)
  28. ^ JA Kimber (2008). "Elasmobranch electroreceptive foraging behaviour: male-female interactions, choice and cognitive ability". dspace.lib.cranfield.ac.uk.
  29. ^ Ryan M. Kempster; Nathan S. Hart; Shaun P. Collin (2013). "Survival of the Stillest: Predator Avoidance in Shark Embryos". PLOS ONE. 8: e52551. doi:10.1371/journal.pone.0052551. PMC 3541397. PMID 23326342.
  30. ^ "SHARK SHIELD DEVELOPED TO PROTECT OCEANGOERS". Highbeam. 9 March 1997. Archived from the original on 11 September 2016. Retrieved 18 May 2016.
  31. ^ Smit, CF; Peddemors VM (2003). "Estimating the probability of a shark attack when using an electric repellent". South African Journal of Statistics. 37: 59–78.
  32. ^ Thomas P. Peschak (2014). Sharks and People: Exploring Our Relationship with the Most Feared Fish in the Sea. 83: University of Chicago Press. p. 256. ISBN 022604792X.
  33. ^ C. Huveneers (2012). Effects of the Shark Shield Electric Deterrent on the Behaviour of White Sharks (Carcharodon Carcharias): Final Report to SafeWork South Australia. SARDI Aquatic Sciences. p. 61.
  34. ^ Ryan M. Kempster, Channing A. Egeberg, Nathan S. Hart, Laura Ryan, Lucille Chapuis, Caroline C. Kerr, Carl Schmidt, Charlie Huveneers, Enrico Gennari, Kara E. Yopak, Jessica J. Meeuwig, Shaun P. Collin (2016). "How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour". PLOS One. 11: e0157717. doi:10.1371/journal.pone.0157717. PMC 4930202. PMID 27368059.CS1 maint: multiple names: authors list (link)
  35. ^ Kempster RM, Egeberg CA, Hart NS, Ryan L, Chapuis L, Kerr CC, Schmidt C, Huveneers C, Gennari E, Yopak KE, Meeuwig JJ, Collin SP (2016). "How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour". NCBI. 11: e0157717. doi:10.1371/journal.pone.0157717. PMC 4930202. PMID 27368059.
  36. ^ "Shark deterrent research reveals interesting results". The University of Western Australia. 17 June 2015. Retrieved 18 May 2016.
  37. ^ Penberthy, Natsumi. "Great white shark deterrent almost 100 per cent effective". Australian Geographic. Retrieved July 4, 2016.
  38. ^ Sydney Pead (27 January 2016). "Shark Shield deterrent gets Choice tick of approval". The Sydney Morning Herald. Retrieved 19 May 2016.
  39. ^ "Effectiveness of five personal shark-bite deterrents for surfers". PeerJ. Retrieved August 31, 2018.
  40. ^ "Research finds surfer shark deterrent significantly reduces the risk of attack". Department of Primary Industries and Regional Development. Retrieved 22 May 2018.

External links[edit]