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…
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.
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| ©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.
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| ©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.
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.
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| 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.
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| 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.
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.
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!
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.
We just came back from our first expedition of the year to Guadalupe Island, where we saw 12 different sharks. As is usual for this time of the year, the smaller males were the most frequent visitors to our cages. On our trip we saw the following sharks that are all in our photo ID database.
#107 Atlantis: He was the first shark that showed up on day one and stayed around all day.
#65 Johnny: He came really close to show off his new mutilation to his tail. He’s now sporting a cut in the center of his caudal fin.
#206 Poseidon: He was super active and made may close passes by the cage.
#97 Drogin: Drogin was his usual self. He’s a super active shark, coming at the cages from all different directions, trying to steal a hang bait.
#188: We can’t leave this shark without a name! How would you like to name him? Contact http://www.marinecsi.org/ and sponsor his name! Make it a cool one! He deserves it!
#149 Kenrick: He was one of the bigger males that showed up and swam around like he’s the boss. He’s still a sub-adult though and won’t be the dominant one, once Bruce, Bite Face, Thor etc. show up.
#168 Sad Face: He was named last year, because he had bite marks that looked like a sad face on his side. This year those marks were barely noticeable, so it’s a good thing that we can use the color markings to positively identify him.
#121 Don Julian: He’s growing up. Last time I saw him, he was probably close to a foot shorter than he is now. Maybe in a couple of years he’ll be mature.
#199 Who wants to name this awesome shark? Contact the Marine Conservation Science Institute to sponsor his name.
#186 He came by with a bunch of pilot fish. He can also be named by contacting http://www.marinecsi.org/
#83 Joker He was pretty shy and didn’t come close.
We also saw a young male with a cookie cutter bite on his head, but I didn’t get any photos of him, so I couldn’t identify him.
Tonight we leave for another trip. I can’t wait to see who else is back at Guadalupe and am ready to meet some new sharks. Last year we added 29 new sharks to our database, how many will it be this year?
Come join us and get to know these awesome creatures. How great would it be to know the individual shark, next time you watch shark week? Call 619.887.4275 or email crew@sharkdiver.com for more information on how to join.
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.
Just as we are about to embark on our first Great White Shark expedition of 2017, there is a piece about Lucy, one of our favorite sharks, in the media. The piece is by none other than Lalo Saidy, our instructor on these expeditions.
Read all about what he had to say and see some great pictures of “Lucy” here.
Come join me and Lalo on one of our expeditions this year. We have just a few spaces left. Let’s find out if Lucy is back again and see who else shows up. Experience your own “real sharkweek” and discover what it’s like to come face to face with a great white shark!
Call 619.887.4275 email crew@sharkdiver.com or visit www.sharkdiver.com for more information.
Lets 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.
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.
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.
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| “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.
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| #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.
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.
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| “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.
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| #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.
“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.
