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Shark OFF at Shark Lab

Lose the Fear

Love the Ocean

                 Deet you

         know that bug

      repellents are

   effective for

 keeping bugs

away but are  bad

for sharks?


The Science - Do Shark Repellents Really Work?

How it Works

You know sharks have superpowers, right? You’ve heard they can smell blood in the water for long distances. It’s true. But did you also know sharks (and rays) can feel the teeniest amount of electricity imaginable? Our patented, non-magnetic active element uses that sensitivity against them harmlessly and naturally.

It’s kryptonite for sharks!

Shark OFF - How it Works

Shark OFF - How it Works

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Want to Know How Shark Repellents Work?

Over 450 million years of evolution have created one awesome apex predator (sharks!). You may have heard that sharks can smell blood from long distances, which is true, but did you also know that they can sense the most minute electrical impulses? Using sensors called the ampullae of Lorenzini (elasmobranchs like sharks and rays have them), they can pick up ridiculously tiny electric signals. 5/1,000,000,000ths of a volt in fact (yes, that’s billionths). This sense is so fine that sharks can detect the heartbeat of another fish. Scientists suspect the ampullae of Lorenzini may be used for hunting – finding other fish in distress, or in murky waters, or even hiding under sand. 

Shark Sensory System Diagram
Shark Snout

Shark OFF turns those very senses against the shark – and over stimulates them. While a super low voltage field (like the rapidly beating heart of an injured fish) may attract sharks, Shark OFF’s higher voltage field repels them. Our patented active element gives off enough voltage to make the shark jerk away from it but it is imperceptible to us. The proprietary alloy that makes up the active element emits an electric field in water of about 1.5 volts – billions of times stronger (literally) than what the shark’s ampullae of Lorenzini can feel. The effect on the sharks is absolutely blinding – but you don’t feel a thing.


Still Not Convinced?

Let's start from the beginning... Shark OFF was born in bed. No, it’s not a bad joke. The founders of Shark OFF, Shea & Geoff Geist, were in bed watching TV one night. Along came a PBS NOVA program (yup, that’s a plug for public TV) called Hunting The Elements - kryptonite for Sharks. David Pogue of NOVA was interviewing one of the scientists that discovered the technology used in Shark OFF. 

As David and Dr. Patrick Rice discussed the shark repellent properties of rare earth elements, we were totally blown away. We were amazed that we had never seen a product using this technology. Why was this not in beach shops EVERYWHERE? 

After pursuing it further, we found that this research was dedicated to the reduction of shark bycatch in commercial fishing and not as a deterrent against human interaction. Inspired by Shea’s debilitating fear of the ocean and the vision of this unmet need, we dived in to bring this amazing technology to beachgoers around the world. 

So, here we are. We love to help people overcome their misguided fears and allow them to better enjoy the peace and beauty of the oceans – all while providing education about sharks, the extremely limited risk of shark attack, and their important role in the ecosystem.

Our commitment to the product and the science doesn’t end here. After successfully testing the product ourselves in July 2018 with the preeminent Shark Lab (Bimini Biological Field Station) in the Bahamas, and another independent study off the piers at Bimini Big Game Club with Neal Watson in 2019, we continue to research and test new alloys. As science evolves, expanding our understanding of the oceans' ecosystems, Shark OFF will take a leading role in bringing those advances, and advantages, to you. 

Smart People

Getting Into It Now?

NOAA Study shark repellent

Exhaustive research has been done into the myriad elasmobranch sensory systems. For the purposes of our research Hueter et al 2004 – Sensory Biology of Elasmobranchs summed up those abilities and offered a relatively simple yet comprehensive explanation of our focus - the ampullae of Lorenzini.

NOAA Technical Memorandum

NMFS-PIGSC-16 November 2008

Shark Deterrent and Incidental Capture Workshop

NOAA Study

Science backed by the world's leading researchers

As the PBS special indicated, these rare earth elements caused strong reactions in elasmobranchs (sharks and rays) using their ampullae of Lorenzini against them. Since this discovery many experiments have been conducted. The studies cited below tested differing lanthanide alloys in a wide variety of water temperatures, locations, depths, species, captive animals, wild animals, tanks, pens, baits, and methods. These present strong evidence showing the efficacy of electropositive metals as a deterrent, especially in the environments we see our products most being used – shallower, warmer and lower-visibility waters.

Shark defense shark repellent study
Shark Defense.JPG

SharkDefense Technologies LLC

NONE of this would be possible without the groundbreaking discovery and continued research of Dr. Eric Stroud and Dr. Patrick Rice at SharkDefense Technologies LLC. While working diligently to save millions of sharks from incidental death, they gave birth to a technology that will help millions experience the ocean with less fear. You would literally not be reading this right now if they had not dedicated their careers to saving millions of sharks accidentally killed by long-line fishing every year.

Shark OFF is proud and blessed to be the sole licensee of  SharkDefense Technologies LLC's electrochemical patent 8,951,544 B2 and to have their full support and incredible knowledge backing our work. Check out their website for all the information you could ever want to read on all the shark repellents they have patented.

Glutton For Punishment, Huh?


Bimini Sharklab

There is no better place in the world for field research on sharks than the Bimini Biological Field Station Foundation. Fact check me. I double dog dare you. Dearly departed Dr. Samuel "Doc" Gruber's crew down in the Bahamas are a top notch group of researchers, PHD's, graduates, students, staff and dedicated volunteers. You will find no shark authority more respected than Doc was and his crew still is.


Shark OFF LLC is grateful beyond words for all of the help, guidance, encouragement and sincere friendship of such amazing people. Doc (RIP), Angela, James, Kristine, Vital, Sofie, Tory and Nikki to name a few will be in our hearts forever. We look forward to many years of testing in the Bahamas, and around the world, to continually make Shark OFF the best.

Shark Lab shark tagging
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Scientific Citations

Shark OFF shark repellent testing
  • Robert E. Hueter, David A. Mann, Karen P. Maruska, Joseph A. Sisneros, Leo S. Demski

       2004 - Biology of Sharks and Their Relatives​

  • Allan W. Stoner, Stephen M. Kaimmer

       2008 - Reducing elasmobranch bycatch: Laboratory investigation of  rare earth metal and magnetic deterrents with spiny dogfish and Pacific halibut​

  • Eric Stroud, Patrick Rice, Shark Defense Technologies, LLC

       2008 – NOAA Shark Deterrent and Incidental Capture Workshop - A Small Demonstration of Rare Earth Galvanic Cell

  • Brill, R., Bushnell, P., Smith, L., Speaks, C., Sundaram, R., Stroud, E., Wang, J.,

       2009 - The repulsive and feeding-deterrent effects of lanthanide metals on juvenile sandbar sharks (Carcharhinus plumbeus).

  • Tallack, S. M. L., Mandelman, J. W.

       2009 - Do rare-earth metals deter spiny dogfish? A feasibility study on the use of electropositive “mischmetal” to reduce the bycatch of Squalus...

  • M.R. Hutchinson, J.H. Wang, K. Holland, Y. Swimmer, S. Kohin H. Dewar, J. Wraith, R. Vetter, C. Heberer, J. Martinez

       2010 - The effects of electropositive metals on shark catch rates and behavior​

  • W.D. Robbins, V.M. Peddemors, S.J. Kennelly

       2011 - Assessment of permanent magnets and electropositive metals to reduce the line-based capture of Galapagos sharks, Carcharhinus galapagensis

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