Estimating the Probability of a Shark Attack When Using an Electric Repellent 

C F Smit, Department of Statistics, University of Pretoria, Pretoria, 0002, South Africa and V Peddemors, Department of Zoology, University of Durban-Westvill, Durban, 4000 South Africa Smit-Electric repellent.pdf 


Key Research Findings;
  1. Shark Shield prevented the sharks from feeding off the bait

  2. The probability of an attack was reduced from 0.70 to about 0.08

The video below provides an overview by Shark Shield to assist in explaining the results achieved in the Smit & Peddemors study of Shark Shield as a deterrent against a shark attack.


Effects of the Shark Shield Electric Deterrent on the Behaviour of White Sharks (Carcharodon Carcharias) 

C. Huveneers, P.J. Rogers, J. Semmens, C. Beckmann, A.A. Kock, B. Page & S.D. Goldsworthy  Huveneers-et-al-2012-Shark-Shield-testing_SafeWork-SA.pdf


Key Research Findings;
  1. Static Test: the Shark Shield significantly increased the time it took the sharks to take the bait, >2x

  2. Dynamic Test; with the Shark Shield turned on there were zero breaches, it stopped and deterred sharks attacking the seal decoy

  3. Shark Shield’s do not attract sharks

The video below provides an overview by Shark Shield and explains the results achieved in the Huveneers study to test Shark Shield as a deterrent against a shark attack.


 

 

Electroreception in Vertebrates and Invertebrates (Shark Shields Do Not Attract Sharks)

Collins S.P. (2010) In: Breed M.D. and Moore J., (eds) Encyclopedia of Animal Behavior, volume 1, pp. 611 - 620 Oxford: Academic Press

This research deals with the common misconseption that Shark Shield's electrical impulses attract sharks, which it does not. As commented to Shark Shield by Collins: "It is true that the electroreceptive system is extremely sensitive (in the µV range). So when extrapolated to moving the positive and negative terminals of say a battery apart (and very long distances), one can say that this amount of charge would be theoretically detected. However, in practical terms and this has been borne out in many behavioural tests, the electroreceptive system is a relatively short distance sense often working in the 30-60cm range. Since these animals use this sense to detect the presence of living prey items that may not be otherwise detected (i.e. under the substrate), they are really working at their detection limits. Therefore, although theoretically the ampullae of Lorenzini can detect very low strength electric fields, they do not use them to track animate objects over these long distances (where other senses such as audition and olfaction are the primary drivers)."
 


 

Ampullae of Lorenzini

The ampullae of Lorenzini are small vesicles and pores that form part of an extensive subcutaneous sensory network system.  These vesicles and pores are found around the head of the shark and are visible to the naked eye.  They appear as dark spots in the photo of a porbeagle shark head below.  The ampullae detect weak magnetic fields produced by other fishes, at least over short ranges.  This enables the shark to locate prey that are buried in the sand, or orient to nearby movement.  

Recent research suggests that the ampullae may also allow the shark to detect changes in water temperature. Each ampulla is a bundle of sensory cells that are enervated by several nerve fibers.  These fibers are enclosed in a gel-filled tubule which has a direct opening to the surface through a pore. The gel (a glyco-protein based substance) has electrical properties similar to a semiconductor, allowing temperature changes to be translated into electrical information that the shark can use to help detect temperature gradients.

READ MORE ABOUT AMPULLAE OF LORENZINI HERE