Ask Ryan, Marine Explorer and Shark Expert

This is your chance to ask and have answered some of your most pressing questions about sharks, the oceans and what it is like spending a life on and under the oceans.

Question: Silver Spring, Md.: Ryan, you mention that you taught yourself how to free dive with great whites; how?! Any hair raising stories you'd care to share? Thanks, and please be careful.

Ryan: How I learned was with a friend of mine, Andre Hartman. He knew how to free dive with white sharks and because I had scientific instrumentation placed on the sea floor in great white hot spots I knew I would encounter them. So Andre took be out a couple days and we jumped in the water together.

The first time you jump in the water with a great white shark without a cage you never forget that moment because you can see every gill flutter and movement of its tail that it makes. It's something that when I close my eyes I remember that first time I hopped in the water like yesterday.

Question: Freising, Germany: What are the waters around Sharkville like? I've heard that great white sharks are usually found close to seal populations around the world, but do they prefer colder waters rather than warmer tropical waters? How do you think that a general warming of ocean waters will affect great white sharks and seals, their prey?

Ryan: Great white sharks have evolved to specialize in hunting marine mammals such as seals. Where the seals hang out is typically in the colder waters so this is where you're gonna find the great white sharks. How they survive in these waters and remain very fast and powerful predators is by elevating their body temperature above the ambient water temperature.

At present it's impossible to predict how global warming will affect the great white shark distribution. One of my doctorate students, Enrico Gennari, is trying to answer just that question through understanding their thermal ecophysiology or their ability to control their body temperature in varying water temperatures.

Question: Silver Spring, Md.: Mr. Johnson, One marine Biologist to another - what do we need to do to help "ordinary" folks understand that sharks aren't man eaters at all. It seems that, ever since Jaws, folks are just so . . . irrationally afraid. The number one questions I get when doing public presentations is "Have you ever seen any sharks" followed by "And weren't you afraid?"

Ryan: That's the most difficult question that all shark conservationists face, trying to remove this irrational fear that many humans have toward sharks. My approach is to try to highlight as many critical behaviors and facts about sharks to try and broaden the public's appreciation of these creatures.

Question: Alexandria, Va.: I keep hearing that because of how sharks have evolved, they are really vulnerable to fishing pressure. Why is this? What can be done to help protect them?

Ryan: Sharks as top predators are very slow to reach sexual maturity. They have few offspring and they live a long time (varies for different species). This means if they are fished out their ability of a population to resist fishing pressure is very poor and they are very slow to recover from overfishing.

Question: Sterling, Va.: I realize that great whites have an innate "cool" factor...but (out of curiosity) could you give a quick explanation of why we should study them? Clearly there is a lot of research that still needs to be done on the Natural World. What is the importance/impact of studying great whites as opposed to anything else? Thanks!

Ryan: As top predators sharks can have a major impact right through the marine food web. To ensure that entire marine ecologies stay stable we have to understand and protect the top of the food chain which is where sharks and the great white are positioned.

Question: What are your thoughts on shark tournaments? Do you think its a brutal event that kills sharks for the glory of a cash prize and the photo op with a bloody carcass on the docks? Or is it a way for scientists to get to observe and dissect carcasses that they would normally not get a chance to encounter? Thanks.

Ryan: I think it's a pointless activity which I could never support in any way. Sharks are captured as bicatch in commercial fishing nets and these specimens provide scientists with enough information for all their research needs. If shark fishing tournaments are carried out they should be catch and release and fishers should be taught how to handle a shark to ensure its survival following release.

Question: Washington, D.C.: I heard that a bill called the Shark Conservation Act of 2008 passed the House of Representatives earlier this month and that now Sen. John Kerry from Massachusetts has introduced it in the Senate. Do you know anything about this bill and how it would help protect sharks off of Martha's Vineyard?

Ryan: This is one of the most fantastic bills that has been introduced to protect sharks and America is the first country to introduce a bill like this that the entire world of shark scientists and conservationists admires. What it does is make illegal for any fisherman to remove the fins of a shark whilst at sea so that any carcass of a shark is returned to land and is utilized in its entirety. This will stop the incredibly wasteful practice of finning sharks and throwing the carcasses away at sea.

-This is legislation I hope the South African government will emulate shortly.

Question: Washington, D.C.: Hi Ryan, How prevalent is taking only pieces of sharks in the wild (e.g. fins for shark fin soup, other body parts as aphrodisiacs)? Do you encounter a lot of this?

Ryan: It's incredibly prevalent and probably a lot more than even I estimate. Due to the fact that most of this fishing happens unobserved. Around Africa many of the developing nations don't have any form of fishing monitoring and huge fishing vessels can do anything with impunity. When I was in Mauritius with National Geographic last month a cyclone arrived and within a day the entire harbor was filled with Asian long-line vessels of which may would have been filled with sharks.

Question: Washington, D.C.: How did you get the night images of the sharks? And what other projects are you working on? I love National Geographic Channel. Nice work.

Ryan: How we got the images was by utilizing thermal imagery cameras which highlighted the thermal fingerprint of the great whites as they exploded out of the water. The white shark elevates its body temperature 5 degrees Celsius above the ambient water temperature which showed up beautifully on the film. Secondly we used night image intensify cameras which were originally developed for military use but have recently been adapted for filming wildlife at night.

Question: New York, N.Y.: Why do sharks jump out of the water sometimes, as we recently saw this week in a photograph taken of a surfer with a shark jumping out of the water right behind him? Also, what are the most frequent causes of death of great whites aside from hunting?

Ryan: The jumping out of the water that great white sharks do is a consequence of the high-speed ambush attacks they attempt on seals. They typically patrol at around 10 meters in water depth looking up for silhouettes of seals. When spotted they accelerate as fast as they can vertically to attack the seal and the momentum carries them out of the water in what we call a breach.

What inspired you to become a marine biologist?

Growing up in New Zealand, it is impossible to be more than a few metres from the ocean, and many of my childhood activities were on the ocean, from sailing, rowing, surfing or swimming. It has been a part of me since I was born and for that reason I love it. Now days, after I have been more educated to the destruction that goes on in the ocean, my love has changed from simply enjoying the ocean to wanting to preserve it.

Why are you so passionate about studying sharks

Initially it was the excitement and adventure of been able to go live on an island (Dyer Island off Gansbaai) for a year and play with great white sharks every day! It was during this year that I discovered how sharks were been over exploited for shark fin soup and that is what has kept me in the research, trying to conserve sharks somehow. I am guilty of believing the great white was a genuine danger to humans for many years, it was only after I started getting up close and personal that my fear turned to admiration and respect.

How do you feel about satellite tagging great white sharks

It is mixed emotions, I have prided myself on developing research techniques that have the least possible impact on the subject sharks. Obviously with attaching satellite tags on dorsal fins we had to hook and constrain the sharks, meaning we were having a big impact. This guilt in impacting them was, however, minimised by knowing that we had some of the world’s top sharks vets on board treating the sharks and that the information we gained could make a tangible difference to the conservation status of the white shark. Nichol’s migration from South Africa to Australia and back was an important part of the white shark being successfully listed in CITES.

Have you ever been scared for your life?

Many times on the highway, but never by a shark. I have been injured many times, like getting hit by a tail etc. But It always has been out of a shark defending itself and not because of aggression directed at me.

Is there ways that people can get involved with your research?

Yes! We have a number of volunteer and internship programs from research to education. Go to our website www.oceans-research.com and apply we would love to have you come help!