Special Great White Shark Expedition

Shark Diver is excited to announce that we will have a very special expedition to Guadalupe Island this fall. From Sept. 8-13 we will have both Nicole Nasby-Lucas, the scientist responsible for the Guadalupe Photo ID database and Tanya Houppermans, a world-renowned underwater photographer on board. Nicole has been studying the white sharks of Guadalupe Island, Mexico since 2001. Her research includes satellite tagging and tracking studies to examine migration patterns and behavior. She also…

How easy is it to dive with Sharks?

One of the big reasons why people never fulfill their dreams or take a leap of faith to try new things is because they fear the process requires a lot of work. So they throw up their hands and say “Forget it. It’s not worth it.”  We are here to tell you that the steps to experiencing an incredible life-changing adventure are easier than you think when you book with Shark Diver. It is our…

Guadalupe Great White Sharks in danger.

I started SCUBA diving and spear-fishing at Guadalupe Island in 1996, 5 years before we started shark diving there. It is during that time that we discovered the Great White Sharks that are aggregating at there. At first it was just the occasional encounter, mainly while spear-fishing, but over the years those encounters grew in frequency and it was not unheard of to see a GWS while SCUBA diving.  My first encounter with a GWS happened…

Why do sharks attack?


Why do sharks attack?

Recently there was another shark attack on a spear fisherman in California and a fatal shark bite at Cocos Island in Costa Rica.  Inevitably when someone gets bitten by a shark, there is speculation about why it happened. “Mistaken identity” is a popular explanation, and of course the people arguing “it’s their home” and the “fill in the blank” kills more people than sharks every year are always ready to chime in.

There are statistics on shark bites, like the “international shark attack files” by the Florida Museum of Natural History, and we have a pretty good idea of how many people actually get bitten by sharks each year. Most of those statistics only collect data on what happened and are recording the circumstances of the attack. Since in very few cases was the shark actually seen before it bit the victim, most of the information we have is only about what the victims were doing before they got bit. When we discount the provoked attacks, like someone pulling a nurse shark by the tail, a fisherman getting bit by a shark he hooked, or like in the case of the Manhattan Beach incident, a fishermen hooking a shark and pulling it through a group of swimmers, very little is known about what the sharks were doing prior to biting the victim.

Obviously I don’t know what those sharks were doing or thinking either, nor do I know what lead them to bite. I wasn’t there and don’t have any firsthand knowledge. What I do have is some first hand knowledge of how some of the shark species implicated in attacks on humans behave and how that behavior might determine why they attack.

I have been diving with and observing Great White Sharks for over 17 years at Guadalupe Island and been around Bull-, Tiger– and Hammerhead Sharks for more than 6. What I found is that there are a lot of misconceptions about how these animals behave. Probably the biggest mistake is that people think “A shark is a shark”, pretty much assuming they all behave the same way.

There are well over 400 species of sharks, with most of them absolutely harmless to humans. Think about it this way. We have the top 10 deadliest sharks list. With an average of fewer than 10 fatal shark bites worldwide each year, that means that if a species is listed as #10, it stands to reason that that species is responsible for fewer deaths than #1, it may in fact only be responsible for a death every 30-40 years. Most of the species responsible for deadly bites on humans are the Great White, Tiger and the Bull Shark.

So let’s take a look at a couple of those species.

Great White Shark

The Great White Shark is probably the most feared animal in the world. Movies like “Jaws” and the way the media reports any encounter with them have instilled fear into most people who contemplate going into the Ocean. The thinking that one drop of blood in the water will cause a huge frenzy and pretty much any shark within 10 miles will come and attack you is very common.

The reality looks a lot different. Did you know that Great White Sharks don’t “frenzy”. In 17 years of observing them, I have never seen a bunch of Great Whites buzzing around a food source or a prey animal. When we put tuna heads in the water, or back when we used chum to attract sharks, we sometimes have to wait for hours for a shark to approach the cages. We could see them swimming below, but even though there was fish blood and Tuna in the water, they would not come up. When multiple sharks are around a food source, they typically measure each other up in order to decide who gets first crack at the food, instead of a free for all frenzy.

If that measuring doesn’t settle it, the bigger shark tends to bite the smaller one to assert it’s dominance. It is only after the pecking order is established, that they go after the food. They give each other space, with the smaller ones only going for the food after the bigger shark is a safe distance away.

Another common belief is that Great White Sharks will attack just about anything, even if they don’t know what it is. My observations have actually shown that Great White Sharks are not only very cautious, but seem to be almost timid. For example, a couple of years ago, a beach towel fell overboard and 3 sharks came to investigate it. 2 of them jerked away and took off, like something was chasing them, while the 3rd shark kept approaching it, jerking away repeatedly, until I lost sight of both the towel and the shark. I don’t know if the shark eventually bit the towel to figure out what it was, but it clearly kept checking it out repeatedly, being very cautious in it’s approach. We have actually observed the same timidness in some sharks when they approached a Tuna head. They clearly smelled the tuna, but when it was pulled slightly when they approached, a lot of them jerked away and would not attempt to bite the tuna until the made several passes to inspect it.

Screaming Mimi, a subadult female Great White Shark swam by my go pro that I had on a 20ft. pole 3 times, coming really close and checking it out, before biting it on the 4th pass. Again, she didn’t just attack, she first checked out the go pro a few times, before she decided to take a bite at it.

Another interesting observation we made is that Great Whites attack a sea lion differently than a seal. If they are not biting their head off, the bite a seal in the butt, because seals swim with their  rear fins, while they bite sea lions in the pectoral fins, which is the way they swim. So if Great Whites know the difference between a seal and a sea lion, I think it’s unlikely they would mistake a surfer for a turtle or a sea lion.

There is a general belief that if you are bleeding, a shark can smell your blood from miles away and will come and bite you. Did you know that the Great White Sharks can differentiate between the blood from different species of fish? There is a distinct difference in how they react when they smell tuna blood, vs. yellow tail blood. So if they can tell the difference between the blood from different fish, it stands to reason that they can tell the difference between human blood and the blood of a seal or fish. Instead of increasing the chance of an attack, I actually think that if you are bleeding you might be even safer. Since your blood is giving the shark a way to know what you are, it actually might prevent an investigatory bite.

So why do White Sharks attack? There are of course different reasons. In the case of the spear fishermen who got bit in California, I believe that the shark wanted the fish and is was not actually going for the diver. When we were spear fishing at Guadalupe Island, we always put the fish on our float and didn’t attach it to our body, so that if a shark wanted the fish, it would not come for us. With surfers and swimmers, since I don’t believe in the mistaken identity, I think that most bites were actually an investigation. After they checked out the victim for a while, they took a bite, trying to figure out what it is.

However, I don’t want to take away the possibility that some of the bites are actual predatory attacks. Bites on humans by Great White Sharks are extremely rare, and the number of actual predatory attacks even rarer. While Great Whites are not mindless killers, out to get us, they are apex predators and definitely not harmless pets. There is no need to fear these animals, but we have to respect them for what they are.

Bull Sharks

We all heard that Bull Sharks are the most aggressive, because they have more testosterone than any other shark. While the testosterone part may be true, it has nothing to do with them supposedly being aggressive. People mistake aggression with hunger. When a Bull Shark is hungry, it has to eat. Unless it finds some animal that is already dead, that means it has to hunt and kill something. That’s not aggression, that’s just simply feeding. Aggression is fighting for territory, dominance etc. and that is actually something that is strangely absent from my observations. In an environment, where up to 70 bull sharks were competing for food, I’ve seen multiple sharks go for a tuna head, without any of them biting the others to get to the food. It was very rare to see a Bull Shark with a bite mark on them, something that definitely can’t be said about White Sharks.

Something I found out in Fiji really surprised me. DaShark, told me that the Bull Sharks that are taking tuna heads offered by hand from a feeder, are not the same as the ones who go for the tuna heads dropped from a trash can. He even told me that sharks that take a tuna head from one particular feeder would not take it from a different feeder. I would have thought that as soon as the sharks smell and see the tuna, they would go for it and not be picky.

Bull Sharks don’t naturally hunt for prey that is human sized, but they do hunt in brackish water, where the visibility can be quite bad. That is also the place where a lot of humans are in the ocean. So I think it’s not the “fact” that they are aggressive and attack anything, but rather their proximity to humans that makes it more likely that they are implicated in an attack. When chasing fish, Bull Sharks are not stalking. They pretty much have to attack at full speed in order to get the fish. When they are hunting, specially around humans, it’s easily possible that a foot flashes in the middle of some fish and the shark bites it by mistake. Also while more common than bites by Great Whites, Bull Shark bites tend to be less severe.

So what does all this mean for anyone going into the ocean? First and foremost, think about the rarity of a shark bite. There are far greater dangers in the oceans than sharks. Currents, waves and heat strokes have killed more people in the ocean than sharks. You are also more likely to get hurt on the way to the Ocean, than by a shark in it. There are however some common sense things you can do though to reduce the extremely small chance of getting bit even further.

1. If you see a potentially dangerous shark, get out of the water while keeping your eyes on it. Since they are stalkers, they are unlikely to attack when they first notice you and since they like to ambush their prey, they are less likely to attack if they know that you see them.

2. Don’t swim at dusk and dawn, when sharks tend to be more active.

3. Avoid shiny jewelry, sharks hunting in shallow water might mistake that for a fish.

4. Don’t go spearfishing or surfing in an area known to have big predatory sharks. In some areas that depends on the time of year.

Again, to put everything into perspective. In California, some of the most famous surf spots are in an area that seasonally has adult White Sharks. The busiest time for surfing is before and after work, dusk and dawn, the time sharks are most likely to hunt. The surfers are on the surface of the water, the most dangerous place in the water, because these sharks tend to attack from below, yet with all that, in 100 years from 1900 to 2000, there were only about a dozen fatal shark attacks. That’s about one every 9 years and those happened all over California, not just the area where White Sharks aggregate.

Bull Sharks can not only swim in salt water, but can go from salt to brackish and even fresh water. That fact means that they tend to be in waters that are also frequented by humans, which naturally increases the chances of that species being implicated in an attack. With the ever growing number of people going into the water, we would expect the frequency of bites to go up every year, something that actually hasn’t happened.

When it comes to our fear of shark, I keep thinking of a quote by President Roosevelt that says: “the only thing we have to fear is…fear itself”.

Go out and enjoy the Ocean. And if you want to observe these awesome animals yourself, let’s go shark diving!

Martin Graf
CEO Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at crew@sharkdiver.com.

Great White Mystery?

In 17 years of diving with the Great White Sharks at Guadalupe Island, we have learned a lot about these awesome creatures. From not knowing where they are heading when they leave the Island, to thinking they are heading to an area offshore to mate, to finding out that we were wrong on that and realizing that they are actually mating at Guadalupe, we have come a long way.

What never ceases to amaze me is the fact that we keep learning new things and that things we thought we knew were actually wrong. Observing them over time has given us some insights into their behavior and how the relate to each other and how their personality changes as they grow. The most important thing I have learned is that just when you definitively think you know something about them, you find out that it may not always be true.

First I have to make a disclaimer. I’m not a marine biologist, so most of what I know about their biology and migration I learned from my friends who are biologists and study these sharks. What I know about their behavior comes from literally thousands of hours spent observing them, both in the water and from above.

The latest theory that has come into question is how the shape of their teeth changes as they growand the reason for that.

Georgina French, a PhD student at the University of Sussex, published a new study that deals with that theory.

From her paper: Up until now, scientists have accepted that white sharks start out their lives with cuspidate (pointy) teeth, which are thought to be adapted for gripping onto slippery fish. When the sharks hit roughly 3m in length, they’re then thought to develop much broader teeth, which are believed to be adapted for catching and eating marine mammals like seals and dolphins. This shift in diet and tooth shape with age/size is referred to an ontogenetic shift.

©Georgina French

Her new discovery seems to be that there is a distinct difference between male and females, something I have never heard before.

She writes: Previous studies of white shark teeth have always lumped males and females in together, despite the fact that they are quite different in other aspects of their biology and ecology. I decided to explore their tooth shape/shark length relationships separately. When I combined all of the data from the photographs, the literature and the KZN jaws, I found startling differences between the sexes.  While males seem to follow the accepted pattern of broadening teeth when they get to about 3m long, females didn’t. Instead, a female of any size could have either broad, pointed or intermediately shaped teeth. Females also didn’t change the angle of their upper third teeth, while males did.

©Georgina French

As with any new discovery, there are instantly a bunch of new questions. In this case, first and foremost, 

What does this mean?

 Broadly speaking, the results indicate that either males and females are feeding on different things as they grow up, or that the tooth shape change isn’t related to diet.
When sharks mate, males hold onto the females using their teeth. It’s possible that the broadening of the teeth and the change in tooth angle found in males could be an adaptation for mating, rather than for handling different prey. Alternatively, females with broad, pointy and intermediate teeth may be specializing on different types of prey i.e. they are polymorphic. I also found significant variation in the size at which males developed their broad teeth, which combined with other evidence indicates that some individuals mature a lot more quickly than others. Polymorphism and differing rates of maturity among individuals can have pretty big ecological consequences, and these factors need to be taken into account in future studies and white shark management.

This is what I love about working and diving with Great White Sharks. Every question that gets answered opens up a lot more questions. I wonder to what new insights about Great White Sharks this new discovery leads to. Maybe we should call these sharks Great White Mysteries instead.

Let’s go shark diving and discover new and exciting things about these awesome animals!

Martin Graf
CEO Shark Diver 

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.

What causes sharks to have crooked spines?

Earthtouchnews has an article describing a bull shark with a crooked spine. That shark was found by the shark lab in Bimini. They named him “Quasimido” and are speculating on what caused that deformity.

The Bimini Shark Lab team secures “Quasimodo” for workup (a short checkup that includes taking various measurements of the animal). Image: Chelle Blais/Bimini Biological Field Station

Sarah Keartes writes: “Dr. Natalie D. Mylniczenko, a veterinarian who has spent time with the Shark Lab beforepresented several possible explanations for the bull shark’s strange skeleton. It’s possible that a deep abscess, granuloma, or slow-growing cancer is to blame – but Quasimodo’s overall state seems to suggest otherwise. If disease were at the root of the deformity, we would expect to see at least some abnormal behaviour. The more likely culprit, according to Mylniczenko, is either a congenital or traumatic incident. In either case, this would have occurred when the shark was very young, and over time, his body would have compensated and healed in a skewed position.”

Read the full story here: https://www.earthtouchnews.com/oceans/sharks/meet-quasimodo-the-bull-shark-with-a-very-crooked-spine/

Image: Chelle Blais/Bimini Biological Field Station

This Bull Shark is not the only shark with a deformed spine. At Guadalupe Island, we have our own Great White Shark with the same deformation. When we first met her a couple of years ago, I nicknamed her “Kinky” because of the very distinct kink in her tail. I have no idea what caused that kink, since she doesn’t have any obvious scars or signs of injury. She was named “Screaming Mimi” by someone through the “Sponsor a shark” program of the Marine Conservation Science Institute. That sponsor program, is one of the ways they raise funds for the Photo ID database at Guadalupe Island.

“Screaming Mimi”

Just like the “Quasimodo” in Bimini who was seen swimming around a couple of weeks after the people from the Shark Lab examined it, “Screaming Mimi” also seems to be doing well and has been very active around our cages at Guadalupe Island.

If you want to meet “Screaming Mimi”, or any of our other sharks at Guadalupe, contact us at 619.887.4275, crew@sharkdiver.com or www.sharkdiver.com

Let’s go shark diving!

Martin Graf
CEO Shark Diver
About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.

What ‘s hurting the Great White Sharks at Guadalupe?

We are coming towards the end of another great season at Guadalupe Island. Just like last year, we added a lot of new sharks to the photo ID database and saw a lot of our regulars that came back. We definitely see an increasing number of sharks, specially for sharks in the 10-12′ range. It’s great to see that conservation efforts seem to have a positive impact on shark numbers. We regularly see in excess of 20 different sharks on our expeditions, a huge increase over 10 years ago, when we were lucky to see 10 and often went whole days without seeing a single shark.

One thing that I noticed though is the increasing number of sharks with injuries caused by ropes or fishing gear. A couple of years ago it was “Luca” that swam around with a rope around his body. Luckily his rope was cut and he’s doing fine. There is just a black scar left that will disappear in a year or so.

Luca with a black scar from a wrapped rope.

This year we saw a few sharks with either fresh wounds from ropes or still having the ropes attached around them. One of these sharks is a new female.

New female with rope around her

The rope around her body is embedded in the gills on both sides.

Her underside shows a faint scar from the rope that was digging into her. (It’ kind of hard to see, just in front of her pectoral fins) The rope goes around her head and into the bottom of her gills on both sides, so it looks like the rope is still inside and the wound has closed around it. She must have gotten that rope wrapped around her quite a while ago, for it to be completely embedded.

This makes at least 3 sharks now that had a rope wrapped around them. Where do these ropes come from?

I hope that somehow this rope can get cut, otherwise I fear that this shark is not going to survive.  We also need to find out where these ropes are coming from, so that we might be able to stop the sharks from getting entangled in the future.

Martin Graf
CEO Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.

Deadly tiger shark stalks stranded diver?


The sensationalist media is at it again, or should I say still at it? This time it’s an outlet not normally prone to sensational headlines. Sky News has a headline that reads Deadly tiger shark stalks stranded diver four miles back to shore”

Tiger Shark

Turns out that a spearfisherman got separated from his boat and had to swim back 4 miles to shore. What they describe as A diver who became separated from his boat has said he is lucky to be alive after swimming miles back to shore while being stalked by a large tiger shark.” and “He swam…in shark-infested waters. I just can’t believe anybody could do that. It’s such a massive effort.”, was in reality just a really long swim, where he encountered a couple of sharks.
That “deadly” shark was just checking him out and the diver even says that “For about 500 metres the shark swam on the same path as me towards the shore and then in a moment banked and disappeared completely as if to say ‘you’re OK now, I’ll leave you alone’. So the real danger to the diver were not the sharks, but the fact that he had to swim for 4 miles to reach shore.

Tiger Shark coming close to a diver

Maybe a headline that says “Diver lost at sea has to swim 4 miles to reach shore” or something similar would be more appropriate than making the sharks out to be those mindless killers again, would be more appropriate.

Me with a Tiger Shark ©Rene Buob

We dive with Tiger Sharks in various places around the world and learned that we have to respect them, but there is no need to fear them. They are neither mindless killers, nor harmless pets, but awesome predators that are curious, but in most cases not interested in attacking us.
Martin Graf
CEO Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at crew@sharkdiver.com.

Six new sharks at Guadalupe Island

This season has started out completely different from the last. Where we had lots of juvenile females early last year, this season it has been all males so far. On our last expedition, we saw 30 different Great White Sharks, with 6 of them being first timers.

The Marine Conservation Science Institute marinecsi.org is keeping the photo ID database and you can contact them if you are interested in naming one of these sharks. I don’t want to keep referring to them as “Unknown 1” etc. Naming a shark is a great way to support the research and how cool would it be if you see “your” shark on sharkweek?

The only female we have seen so far this season is “Screaming Mimi”. She is as active and curious as she was last year and has given our divers many memorable moments.

Aside from all the new sharks, we have also been visited by a lot of our regulars. Bruce, Bite Face, Chugey, Andy, Hunter, Silent Hunter Bolton, Ace, El Diablo, Johnny, Jacques, Mickey, Sad Face, ChumChum, Thor, Atlantis, Drogin, Joker, Monkey, Hooper, Horizon along with a few that are as of now unnamed, have all made an appearance. We had 30 different individuals on our last expedition!

Here are a few of our new sharks.

To sponsor one of these beauties, contact MCSI here.

To join us on one of our expeditions, contact crew@sharkdiver.com or call 619.887.4275

Let’s go shark diving!

Martin Graf
CEO Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.

The big white sharks are back at Guadalupe!

We just got back from our second Great White Shark expedition to Guadalupe Island last night and are happy to report that the big boys are back in town! On our first day, Bite Face showed up. He has been present every single year, since we first met him in 2001. A little after Bite Face, Chugey made an appearance and chased some hangbaits by the cages. Chugey has been a regular since 2004. On day two, Bruce, one of the biggest males we regularly see came back. Bruce has also been there every season since 2001.

Chugey with the Smyth family at Guadalupe Island

It is absolutely amazing to see how these sharks come back year after year. To think that we see the same individuals for this many years just blows my mind.

Aside from these guys we originally encountered during our first year at Guadalupe back in 2001, some of our other old time favorites showed up as well. Mau whom we first met in 2006, Johnny from 2005, Joker, Drogin and El Diablo from 2007 are all back. That is eight sharks that have all been there every single years for at least 10 years!

Jeanine with El Diablo

Of our more recent acquaintances, Monkey from 2011, Hooper and Luca Arnone from 2013, #186 from 2016 (he needs a name by the way, contact MCSI to sponsor his name) and finally Husker, Mickey and Poseidon who first showed up last year all made an appearance.

#205 Mickey

This season has been different from last year, where we encountered many small females in early August. This year it’s been all males. It never ceases to amaze me that after all these years diving with the Great White Sharks at Guadalupe, they keep surprising us. For anyone trying to figure them out, in my experience, I find them to be predictably unpredictable.

Come join us on one of our expeditions and find out first hand that experiencing these amazing creatures in real life is completely different from anything you see on TV.

Call us at 619.887.4275 or email crew@sharkdiver.com for more info.

Let’s go Shark Diving!

Martin Graf
CEO Shark Diver
About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.