Great White Mystery?

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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!

Cheers,
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?

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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.
Cheers,
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.

How can you have your own private “Shark Week”?

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Next week we start our 17th season at Guadalupe Island, diving with Great White Sharks.

Kinga Phillips has been coming out with us twice so far, and she’s written an excellent blog about her experience and how you can have your own private shark week.

I like how she described the Great White Shark: “The highlight of the trip is spending cage time face to face with one of nature’s most incredible examples of the perfect predatory form. So perfect evolution took one look at her design roughly 100 million years ago, dropped the mic and walked away.”

She provides a lot of insight, not just about the actual experience of diving with Great White Sharks, but about conservation and eco tourism as well.

Read her entire blog here

For more information on how you can experience your own “real sharkweek”, call us at 619.887.4275, email crew@sharkdiver.com or visit www.sharkdiver.com

Let’s go Shark Diving!

Cheers,
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.

Get to know the Great White Sharks of Guadalupe Island

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Over the last couple of weeks I wrote about a few of the Great White Sharks we encounter at Guadalupe Island. Before I introduce you to more of those, I want to tell you a bit about the sharks we are less familiar with. While we have a lot of sharks we see every year, or every other year for the females, there are many that don’t follow that pattern. Some sharks we have only seen during one season, while others visit Guadalupe at irregular intervals.

“Geoff Nuttall” was a regular from 2003 until 2011, then he wasn’t seen for 2 years, before returning to his annual returns in 2014.

“Geoff Nuttall”

Quezalcoatl, #58 in our database was first seen in 2005 and then didn’t appear until 2013, an absence of 8 years. Where did he go during those 8 years? While we have really good tracking data from the sharks that were outfitted with satellite tags, showing the migration pattern of the sharks we see regularly, we have no data on where the shark we see infrequently are going. There is so much we don’t know.

#56 Quetztalcoatl

Dr. Bob, a very curious and active 13″ sub-adult shark only visited in 2014, the now world famous “Deep Blue” was seen in 1999 and then again in 2012. “Lou”, “Oscar” and “Hefe” all had absences of 6 or more years, before showing up again. Some of these absences may simply be due to them not showing up at the cages during those years. We simply don’t know.

Below is a video of “Dr. Bob”. Check out his bite marks on the right and look at his eyes as he swims over the camera. He’s looking straight down at the divers.

My favorite shark, “Shredder” has not been seen since 2011, after 11 continuous years at Guadalupe. I hope that his absence is just like those of the other sharks that were taking a break from visiting Guadalupe, but I have to say that I’m worried about him. He’s never been the most careful individual in the first place, as evidenced by his many scars and mutilations.

Anyway, I can’t wait to go back to Guadalupe and see who’s back. I’m equally excited to meet some new sharks. In the last 2 years we added over 50 new individuals to our database! Are they going to be back? Come join us for a real “sharkweek” and find out!

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

Let’s go Shark Diving!

Cheers,
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.

Get to know the Great White Sharks of Guadalupe Island

Instagram 
Over the last couple of weeks I wrote about a few of the Great White Sharks we encounter at Guadalupe Island. Before I introduce you to more of those, I want to tell you a bit about the sharks we are less familiar with. While we have a lot of sharks we see every year, or every other year for the females, there are many that don’t follow that pattern. Some sharks we have only seen during one season, while others visit Guadalupe at irregular intervals.

“Geoff Nuttall” was a regular from 2003 until 2011, then he wasn’t seen for 2 years, before returning to his annual returns in 2014.

“Geoff Nuttall”

Quezalcoatl, #58 in our database was first seen in 2005 and then didn’t appear until 2013, an absence of 8 years. Where did he go during those 8 years? While we have really good tracking data from the sharks that were outfitted with satellite tags, showing the migration pattern of the sharks we see regularly, we have no data on where the shark we see infrequently are going. There is so much we don’t know.

#56 Quetztalcoatl

Dr. Bob, a very curious and active 13″ sub-adult shark only visited in 2014, the now world famous “Deep Blue” was seen in 1999 and then again in 2012. “Lou”, “Oscar” and “Hefe” all had absences of 6 or more years, before showing up again. Some of these absences may simply be due to them not showing up at the cages during those years. We simply don’t know.

Below is a video of “Dr. Bob”. Check out his bite marks on the right and look at his eyes as he swims over the camera. He’s looking straight down at the divers.

My favorite shark, “Shredder” has not been seen since 2011, after 11 continuous years at Guadalupe. I hope that his absence is just like those of the other sharks that were taking a break from visiting Guadalupe, but I have to say that I’m worried about him. He’s never been the most careful individual in the first place, as evidenced by his many scars and mutilations.

Anyway, I can’t wait to go back to Guadalupe and see who’s back. I’m equally excited to meet some new sharks. In the last 2 years we added over 50 new individuals to our database! Are they going to be back? Come join us for a real “sharkweek” and find out!

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

Let’s go Shark Diving!

Cheers,
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.

Get to know “Luca Arnone” Great White Shark at Guadalupe Island

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“Luca Arnone” listed as #163, is one of our recent additions to the photo ID database at Guadalupe Island. We first met him in 2013 and he has been coming back every year since.

Last year “Luca” looked a bit rough. He was partially wrapped in a thick rope, which fortunately was being removed by Dr. Mauricio Hoyos, the local researcher at Guadalupe Island. The cut caused by the rope was not too deep and since white sharks have an amazing ability to heal, it should not cause him any permanent harm.

“Luca” is a fairly small shark, probably just shy of 12′, but he doesn’t seem to mind the bigger sharks and is a frequent visitor to our cages. 

Luca was named by one of our diver, who named 2 different sharks, one after his son, Luca and the other after his daughter Milana. Naming a shark is one way you can support the ongoing research at Guadalupe Island. The Marine Science Conservation Institute, “MCSI” who maintains the photo ID has various levels of sponsorship available, including naming a shark.

Another way you can support “MCSI” is by coming on one of our “science” trips. A portion of these expeditions goes to fund the research and Nicole Lucas-Nasby, the researcher maintaining that database is coming along as the host. She is sharing the results of her research with you and if we encounter a new shark, you’ll also have an opportunity to name that shark. How cool would it be, if you see a shark that you named on “Sharkweek”?

If you want to find our for yourself what it’s like to come face to face with a great white shark and maybe name one of these sharks, come join us on one of our expeditions. We do have some spaces open and would love to introduce you to our sharks.

Call 619.887.4275, email crew@sharkdiver.com or visit www.sharkdiver.com for more information.

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.

Get to know “Luca Arnone” Great White Shark at Guadalupe Island

Instagram 
“Luca Arnone” listed as #163, is one of our recent additions to the photo ID database at Guadalupe Island. We first met him in 2013 and he has been coming back every year since.

Last year “Luca” looked a bit rough. He was partially wrapped in a thick rope, which fortunately was being removed by Dr. Mauricio Hoyos, the local researcher at Guadalupe Island. The cut caused by the rope was not too deep and since white sharks have an amazing ability to heal, it should not cause him any permanent harm.

“Luca” is a fairly small shark, probably just shy of 12′, but he doesn’t seem to mind the bigger sharks and is a frequent visitor to our cages. 

Luca was named by one of our diver, who named 2 different sharks, one after his son, Luca and the other after his daughter Milana. Naming a shark is one way you can support the ongoing research at Guadalupe Island. The Marine Science Conservation Institute, “MCSI” who maintains the photo ID has various levels of sponsorship available, including naming a shark.

Another way you can support “MCSI” is by coming on one of our “science” trips. A portion of these expeditions goes to fund the research and Nicole Lucas-Nasby, the researcher maintaining that database is coming along as the host. She is sharing the results of her research with you and if we encounter a new shark, you’ll also have an opportunity to name that shark. How cool would it be, if you see a shark that you named on “Sharkweek”?

If you want to find our for yourself what it’s like to come face to face with a great white shark and maybe name one of these sharks, come join us on one of our expeditions. We do have some spaces open and would love to introduce you to our sharks.

Call 619.887.4275, email crew@sharkdiver.com or visit www.sharkdiver.com for more information.

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.

Get to know “Scarboard” Great White Shark at Guadalupe Island

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“Scarboard” is another one of my favorite sharks. You’re probably beginning to see a pattern here. I have a lot of “favorite” sharks. It’s is amazing how all these sharks have different behaviors. Some are a bit skiddish, others are seemingly relaxed without a care in the world. Observing them for 16 years, I have grown attached to these guys and girls. However, as I always point out, I absolutely love these sharks, I’m crazy about them, but it is NOT a mutual feeling. As much as some people want you to believe that they just want to be hugged, they really don’t. They are awesome predators, not out to get us, but they are not harmless pets either.

“Scarboard”

Scarboard is a massive female shark, one of our biggest at Guadalupe Island at around 19′. When we first met her in 2002, she was already huge. Like most of our adult females, she shows up at Guadalupe Island every other year. After getting mating at Guadalupe, she is spending the year in between offshore, before giving birth off the coast of Baja or in the Sea of Cortez. She doesn’t have any mutilations, like “Lucy” and so many others, but she does have a very unique characteristic that makes identifying her easy. She has a very distinct line from her nose halfway to her dorsal fin. Where most Great White Sharks‘ lines have a continuous curve, Scarboard’s is straight.

“Scarboard”

After we first encountered her in 2002, she came back in 04 and 06, but then we didn’t see her again until 2011. We don’t know, if we simply didn’t see her, or if she stayed away from Guadalupe for 5 years.

When we don’t see a shark during the season we expect to see them, we always worry that something might have happened to them. Luckily, sometimes, like in Scarboard’s case, we worry about nothing. Where do they go during that extended time away from the Island, what do they do? There is so much we don’t know about those sharks.

The first time we saw Scarboard, after her 5 year absence, I was in the middle of our 2 cages, she slowly swam by the first cage, checking out each individual diver and when she came to me, she looked me straight into the eyes, stopped and did a 180 degree turn, looked at me again, swam off, turned and swam back at me, stopped again, turned and swam off. It looks like that she recognized me, even after a 5 year absence.

Last season “Scarboard” was being used for protection by some bait fish. I’ve never seen anything like that before. When she swam by, she looked like the “Bearded Lady”.

Scarboard the “Bearded Lady”

 
A lot of people are surprised to learn that Great White Sharks recognize individual divers. The fact that they do is not as strange as it seems. We know of lots of fish that recognize divers. Groupers that have a favorite individual they follow around, moray eels that come out of their holes when they recognize a diver, Wolf eels that wrap themselves around the neck of an individual etc. It’s important to remember though, just because White Sharks recognize individual divers, doesn’t mean that they “love” us, want to be petted, or have any feelings towards us. We need to respect them for what they are, amazing predators, neither mindless killers, nor harmless pets.

For me there is nothing quite like seeing a familiar shark and realize it recognizes me as well. It still amazes me that we keep seeing the same individuals on a regular basis. They migrate thousands of miles, but come right back to the same spot.

If you want to find our for yourself what it’s like to come face to face with a great white shark and want to learn how to identify these sharks, join us on one of our “science” expeditions. We do have some spaces open and would love to introduce you to our sharks.

Call 619.887.4275, email crew@sharkdiver.com or visit www.sharkdiver.com for more information.

Let’s go shark diving!

Cheers,

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.

Get to know “Scarboard” Great White Shark at Guadalupe Island

Instagram 
“Scarboard” is another one of my favorite sharks. You’re probably beginning to see a pattern here. I have a lot of “favorite” sharks. It’s is amazing how all these sharks have different behaviors. Some are a bit skiddish, others are seemingly relaxed without a care in the world. Observing them for 16 years, I have grown attached to these guys and girls. However, as I always point out, I absolutely love these sharks, I’m crazy about them, but it is NOT a mutual feeling. As much as some people want you to believe that they just want to be hugged, they really don’t. They are awesome predators, not out to get us, but they are not harmless pets either.

“Scarboard”

Scarboard is a massive female shark, one of our biggest at Guadalupe Island at around 19′. When we first met her in 2002, she was already huge. Like most of our adult females, she shows up at Guadalupe Island every other year. After getting mating at Guadalupe, she is spending the year in between offshore, before giving birth off the coast of Baja or in the Sea of Cortez. She doesn’t have any mutilations, like “Lucy” and so many others, but she does have a very unique characteristic that makes identifying her easy. She has a very distinct line from her nose halfway to her dorsal fin. Where most Great White Sharks‘ lines have a continuous curve, Scarboard’s is straight.

“Scarboard”

After we first encountered her in 2002, she came back in 04 and 06, but then we didn’t see her again until 2011. We don’t know, if we simply didn’t see her, or if she stayed away from Guadalupe for 5 years.

When we don’t see a shark during the season we expect to see them, we always worry that something might have happened to them. Luckily, sometimes, like in Scarboard’s case, we worry about nothing. Where do they go during that extended time away from the Island, what do they do? There is so much we don’t know about those sharks.

The first time we saw Scarboard, after her 5 year absence, I was in the middle of our 2 cages, she slowly swam by the first cage, checking out each individual diver and when she came to me, she looked me straight into the eyes, stopped and did a 180 degree turn, looked at me again, swam off, turned and swam back at me, stopped again, turned and swam off. It looks like that she recognized me, even after a 5 year absence.

Last season “Scarboard” was being used for protection by some bait fish. I’ve never seen anything like that before. When she swam by, she looked like the “Bearded Lady”.

Scarboard the “Bearded Lady”

 
A lot of people are surprised to learn that Great White Sharks recognize individual divers. The fact that they do is not as strange as it seems. We know of lots of fish that recognize divers. Groupers that have a favorite individual they follow around, moray eels that come out of their holes when they recognize a diver, Wolf eels that wrap themselves around the neck of an individual etc. It’s important to remember though, just because White Sharks recognize individual divers, doesn’t mean that they “love” us, want to be petted, or have any feelings towards us. We need to respect them for what they are, amazing predators, neither mindless killers, nor harmless pets.

For me there is nothing quite like seeing a familiar shark and realize it recognizes me as well. It still amazes me that we keep seeing the same individuals on a regular basis. They migrate thousands of miles, but come right back to the same spot.

If you want to find our for yourself what it’s like to come face to face with a great white shark and want to learn how to identify these sharks, join us on one of our “science” expeditions. We do have some spaces open and would love to introduce you to our sharks.

Call 619.887.4275, email crew@sharkdiver.com or visit www.sharkdiver.com for more information.

Let’s go shark diving!

Cheers,

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.

Get to know “Screaming Mimi” Great White Shark at Guadalupe Island

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We met “Screaming Mimi” a couple of years ago. When I first encountered her, I nicknamed her “Kinky”.  She has a 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.

Mimi is a very active and curious shark. When she encounters something new in the water, she exhibits a typical white shark trait. Unlike what most people think, white sharks don’t just attack when they encounter something they don’t know. They swim by close to check it out. It is actually quite funny some times. A couple of years ago, a beach towel blew overboard and started to drift down. 3 white sharks came by to investigate it. 2 of them jerked away and rapidly swam away, when the towel moved a little in the current. The 3rd. one kept swimming close to it, jerking away, and getting closer again. I don’t know if it eventually bit the towel or not, as I lost sight of both the shark and the towel in the distance.

Watch the video below of Mimi checking out my gopro camera that was attached to a long pole and handled from the boat.

You can see that they don’t just attack something they don’t know. The swim by and check things out first.

Screaming Mimi ©Tim Peterson

Mimi also likes to swim really close to the cages and makes eye contact with the divers.

Mimi is around 14′ long and not quite mature yet. It is amazing how big these sharks have to be, before they are mature and able to reproduce.

I hope we’ll see her again this year. She loves to swim around the cages, sometimes for hours. It never ceases to amaze me that we keep seeing the same individual sharks year after year. It’s not like they are resident sharks. The migrate thousands of miles each year, but come right back to the same spot at Guadalupe Island.

If you want to come face to face with a great white shark and would like to learn how to identify these sharks, join us on one of our “science” expeditions. We do have some spaces open and would love to introduce you to our sharks.

Call 619.887.4275, email crew@sharkdiver.com or visit www.sharkdiver.com for more information.

Let’s go shark diving!

Cheers,

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.