Don’t ever watch Jaws the night before an underwater adventure with your metal detector!
I wish someone had given me that same advice last summer.
If you’re about to embark on a scavenger hunt below sea level, I don’t blame you for being nervous about a shark approaching you.
I can’t guarantee you won’t, but I can promise you one thing.
Sharks are not attracted to metal detectors, no matter what you’ve read.
So, if you’re looking for a pep talk or a reason to be hopeful, you’ve come to the right place.
Do Metal Detectors Attract Sharks: the Facts
In 2021, there were a total of 137 shark attacks worldwide, 73 of which were classified as unprovoked.
According to the Florida Museum of Natural History’s IASF, 9 of the 73 attacks ended in a fatality.
Of the 9 fatalities, only 1 occurred in the United States.
Now I’m not saying that it isn’t scary, but considering the number of beachgoers, surfers, and divers each year, the total attacks are extremely low.
But hey, you’re going deeper than a surfer. And you’ve got a metal detector sending out a pulsing signal that suddenly feels like a target on your back.
So for my underwater Diggers, let’s talk about it.
Some might consider sharks the premier predator of the seas. With how movies and sometimes actual events portray them, it’s only natural to have a healthy amount of fear in their presence.
There are many tools a shark uses to hunt for prey, one being electroreception.
Electroreception is the sensitivity a shark possesses toward electromagnetic fields. Their level of electrical sensitivity is the greatest of any living non-human species.
Not only do they use their electroreceptor organs to navigate the oceans, but it’s also a way to locate their target (i.e., fish).
These organs, known as the ampullae of Lorenzini, are spectacular at detecting the electromagnetic fields that every living thing generates.
In fact, the bigger the shark, the longer its ampullary tubes are, making them more sensitive than others.
You might be shouting at me right now; electromagnetic fields are how my metal detector works!
We’ll get to that in a second.
What’s important to know is that sharks are attracted to a frequency of only 20 to 60 cycles per second.
For those metal detectorists familiar with the frequency of your metal detector, 60 cycles per second are equivalent to 60 Hertz, or 0.06 kHz.
Frequencies higher than this don’t attract sharks to your area.
Below is a data table from a study by the Institute of Marine Science at the University of Miami.
Scientists could establish a relative baseline when testing the attraction levels of different low-range frequencies.
Metal Detector Facts
Ok, now for your metal detector.
What role does it play, and how does it answer the question, are sharks attracted to metal detectors?
Let’s say you use a Minelab Excalibur II metal detector with a maximum depth of 200 feet of underwater performance.
Its lowest frequency setting of 1.5 kHz is way too high to attract a shark.
That’s a signal of 1500 Hertz, compared to the 60 Hertz a shark is tuned to.
As far as metal detectors go, 1.5 kHz is reasonably low. Actually, most detectors operate with a low of 3 kHz and above.
So no matter the model you use underwater, you won’t need to worry about drawing the attention of nearby sharks.
Does Metal Repel Sharks?
What about the metal in your metal detector? Or the metal you uncover while down below?
Believe it or not, some metals do repel sharks.
An American chemist, Eric Stroud, discovered that magnets can overwhelm the electroreceptor organs of sharks within 10 inches of proximity, creating an electrochemical repellent.
Here’s a video demonstrating his 2004 discovery.
Magnets aren’t the only metal that repels sharks.
Any metal classified as electropositive will have this effect because of its ability to generate substantial voltage when submerged in seawater.
Some elements found in these metals are sodium, lithium, cesium, and potassium.
Unfortunately, the repulsion power of magnets and other EPMs lasts just 48 hours before corrosion sets in.
Why Do Sharks Not Attack Scuba Divers?
Just because magnets create a minimal barrier against shark attacks doesn’t mean you need to cover yourself in them.
Sharks don’t typically attack scuba divers, with or without a metal detector.
The biggest reason is that humans aren’t very appetizing to a shark.
When they attack, it’s generally out of confusion or the sense that they are threatened.
You see, if you’re diving alone and the waters are murky, a shark might mistake you for a different kind of prey.
Or if you see a shark nearby and start panicking, splashing about as you try to swim away, the shark could switch to the old fight or flight mode; usually, fight.
Another good reason sharks don’t attack scuba divers is that you’re deep underwater.
Usually, a shark goes into hunter mode near the surface when other animals are generally injured or dead. At this point, they’re an easy target.
How to Fight Off a Shark
If a shark attacks, your best method of fighting it off is to attack its exposed areas of weakness.
They have tough skins, so the main points of focus should be their gills, eyes, and snout.
You’re not going to knock out a shark, but you can make it feel like retreating is the safest option.
Use whatever you can to do this. For metal detecting divers, use that metal detector to do as much damage as possible.
When in doubt, use your hands to claw at the vulnerable areas, always being sure to keep the shark in front of you to avoid attacks from your blind spot.
I’m not trying to scare you, but it’s better to know this stuff than feel completely helpless.
What to Do if a Shark Approaches You?
So we know that a metal detector won’t attract any sharks. And you also have some general idea of how to fight against an attack.
But in a perfect world, if a shark comes swimming by, there are two actions to take to ensure your safety.
First, if a shark approaches you, the first thing to do is to not panic and remain still.
Most likely, the shark will pass by without any care for what you’re doing.
Second, gather around others for support.
Hopefully, you’re diving with a group or friend. If so, signal them without any sudden movements or flashing of lights.
You don’t want to give the shark any reason to have their guard up.
Gathering together as a group will tell the shark that you’re not an easy target if they mistake you for food.
Almost every time, doing these two things will send your shark back the way it came.
Finally, keep these last thoughts in mind before you submerge as some experienced bit of advice when metal detecting underwater.
- Only dive when the visibility is good. Sunrise and Sundown are not your friends.
- Don’t detect in an area where there are groups of smaller fish that might be of interest to a shark.
- Leave your jewelry on the boat. Shiny watches, bracelets, or even neon lanyards could look awfully like a fish destined to be a meal.
Are Sharks Friendly?
Hmm, it’s an interesting question. While you’re down below metal detecting, you might come into contact with a curious shark nosier than the rest.
I’ll just say you’re braver than I am if you’re trying to make friends.
But to be fair, not all sharks are bad. I suppose many of them you could consider to be friendly.
The trick is to know the different species of sharks.
For instance, the leopard shark is the friendliest, actually seeking out human interaction without the intent of using its teeth.
And while there are over 300 different species, human attacks are rare.
Is that friendly enough for you?
But I wouldn’t test your luck if you’re in the wild. An aquarium setting is different as those sharks are more used to human interaction.
However, I don’t think you’d find anything interesting with your metal detector in a shark tank.
To wrap up, sharks are not attracted to metal detectors. So if you’re excited yet nervous about your first trek underwater, don’t worry about being the main course of someone else’s meal.
The frequency of your metal detector is too high to confuse a shark into thinking you’re bait.
But the safest approach is staying calm with others nearby when you’re in the presence of a shark while metal detecting.
And if you’re looking for a top-notch metal detector to take with you, pop over to my review of the best metal detectors for the beach and water.
Until next time Diggers!