I'm David Shiffman (@WhySharksMatter) , a shark scientist at the University of Miami. Happy Shark Week! AMA!

Hey David, I think its great you're doing this AMA, especially timely during a Shark Week frustratingly devoid of science. Thanks for all your tweets and FB posts about shark week, I'm so grateful for your voice of reason and humor!

Do you think Discovery Channel will ever produce a Shark Week that shark scientists and conservationists can all in good conscience get 100% behind or is it a lost cause?

edit: spelling

Yes! Did you see "Alien Sharks" last night? It was SO GOOD! Natural history, real science, no sensationalism. It's exactly what Shark Week used to be.

How do you feel about the shark week controversy regarding the first documentary on the megladon? What should discovery channel do in regards to it?

In the interest of keeping language safe for work, I'll refer you to an interview I did on CNN earlier this week about the megalodon nonsense:

http://thelead.blogs.cnn.com/2013/08/07/scientist-slams-discoverys-shark-week-fake-documentary/

I think Discovery should apologize, but they won't.

There are so many true, interesting things related to sharks they could have done, why the hell did they have to start making shit up?

I look forward to Shark Week every year because I like to learn about sharks.. This is disappointing.

Preach!

Are you really supposed to punch a shark in the nose if they attack you or is that just a myth?

If I punched you in the face, would you run away or punch me back?

Hey David! Thanks for doing this AMA. Just want to say thank you. My girlfriend was a student of yours at SeaCamp when she was younger and your love for sharks shaped her into the scientist she is today. She's currently pursuing her masters degree in biological oceanography. I too work in the sciences and feel like communication with the general public about scientific issues is getting increasingly important. What's the hardest part of talking about controversial scientific issues with people who may not know a lot about them?

Hi! Tell your girlfriend hello for me.

The hardest part about communicating "controversial" science (which typically, these days, means climate change and alternative energy issues) is communicating uncertainty. Scientists often talk in terms of uncertainty, but when the public hears it, they think "scientists aren't really sure".

Second question: I don't have anything to do with marine biology, I don't live near the coast, I don't know lots of kids to teach. What can I do to help you with conservation?

There are LOTS of things that you can do to help the ocean, even far from the coast! You're doing the most important one right now: asking questions and learning about it!

The single most important thing you can do, in my opinion, is to purchase only sustainable seafood, and to encourage others to do the same. The single greatest threat facing our oceans (including sharks) is unsustainable commercial fishing.

What's the most important job sharks do?

Sharks help keep the ocean food chain healthy. Where I'm from outside of Pittsburgh, we used to have wolves. Then we killed all the wolves. Now there are too many deer and not enough food for all of them. The deer leave their traditional habitat and cause billions of dollars of property damage each year.

$Billions?? What the hell do these Pittsburgh deer eat?

If we only took care of this deer problem, we could double NASA's budget!

It's not just what they eat, it's what they destroy. Cars, fences, windows of homes.

Do you think academic universities will ever recognize this kind of outreach as equally important to lab achievements?

I remain cautiously optimistic. I'm blessed with an adviser and department that encourage me to do online outreach.

Well we (me and /u/iamapillow and many other people) are thrilled to have you joining us to answer questions. Thanks!

Thank you!

What abilities/perks does a shark possess that a human should be jealous of?

Sharks have the ability to detect electromagnetic fields given off by prey. I feel like that would be pretty sweet.

What is the craziest/scariest shark you have seen in person? What sharks are out there that haven't made it into the public eye?

I wrote my Duke admissions essay about a time in high school that I went SCUBA diving in a shark tank and stared down a 12 foot sand tiger shark. The most scared I've ever been, however, was the time I saw a bull shark on my first night dive. I was 15. And let's just say it's a good thing that my wetsuit was black.

I've always wondered though about those black wetsuits. Aren't they seal-looking like? I saw an ad the other day for a white and blue "camouflage" wetsuit and a striped "anti-shark" suit. Is there anything to that?

I'm skeptical, but they look awesome.

1. what is your favorite shark and why?

2. What were obstacles you faced in your career path?

3. Is it possible for a thirtysomething to change careers and pursue this?

1) Sandbar sharks. They were my Masters study animal have a special place in my heart.

2) I've been fortunate. I think my parents sort of always assumed that I'd grow out of this and become a lawyer or doctor, but they've been very supportive. Dad has even come on the research boat with me.

3) Totally.

awesome! I got married in an aquarium and have a picture of me and the husband with a sandbar shark in the background.

Thanks so much for doing this AMA. I want to go back to school really bad and find a few weeks long volunteering gig working with Shark researchers, to help get my foot in the door experience wise, this is inspiring me to really go for it.

Tweet me @WhySharksMatter, happy to give some more specific (and private) advice

Hi David! It's been a pleasure following you on Twitter the past few months, especially this week. I have a Masters in Epidemiology & Biostatistics, but like this commenter I've always had loved sharks and the ocean. My epidemiology degree is a public health degree but is this something that could translate to the oceans? To sharks? It would be an absolute dream to be able to do what you do.

PS - I did my undergrad at Maryland, I'm going to miss the Duke games...

Sure! There is a place for basically any scientific background to apply research towards marine science and sharks.

I'm sorry you went to Maryland, but nobody's perfect.

How do you feel about sharknado being so popular?

Pro.

Though the sequel title they chose, "SharkNado: The second one," is lame. I suggested "SharkNado Harder"

What about SHARKNADO: SHARKER, SharkNado Sharkie Goes West, SharkNado: A Good Day to Shark hard, SharkNado In Vegas: CardSharks, SharkNado in Space: Shark Trek, Thy Holy SharkNado: Noah's Shark

All better than "the second one"

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Check out SeaCamp, a marine science camp in the Florida Keys. I went there for 5 years and taught there for 2.

Hi. Thanks for doing this AMA.

I grew up in the Caribbean and some folklore said that sharks don't urinate in the wild thus making their bodies decompose very quickly after death and humans shouldn't consume their flesh. Is this based on any truth?

Very, very, very loosely. Sharks have urea in their tissues, which they use for osmoregulation. But sharks, like all animals, do excrete waste.

How difficult is it to collaborate with China for shark conservation considering shark fin soup is a delicacy there?

Attitudes are changing, particularly among the youth in China

What's one weird thing that not many people would know about a shark or sharks?

There are more than 500 species of sharks, and a new species of shark, skate, or ray has been discovered approximately every two weeks for the last decade. Most people only hear about the sharks that bite people.

There seems to have been quite an increase in shark attacks in recent years, at least around my area (Australia).

Do you think that has more to do with increasing shark numbers, more people in the water or changes in weather?

Shark "attacks" increase slightly just about every year. The leading theory is that there are just more people in the water.

1) Do sharks really have 7 sets of teeth?

2) Can sharks get cancer?

3) Does punching a shark in the snout actually do anything?

Some species of sharks have much more than 7 sets of teeth. Sharks can't go to the dentist, and they often bite big, tough animals. Teeth fall out and it's helpful to be able to replace them.

Sharks do get cancer. Every animal gets cancer. Even if they didn't, eating shark cartilage pills wouldn't help cure cancer, any more than I'd get better at basketball if I ate Michael Jordan.

What is the least scary thing about sharks?

Goblin sharks can be bubble gum pink.

What are some of the biggest misconceptions about sharks out there and what can those in the Ocean and Conservation world do to correct it?

Due in no small part to Shark Week, people are afraid of sharks. The best thing you can do is tell your friends and family the truth.

How do you feel about duck-sized horses?

Thank you for this question that I definitely didn't plant via twitter after days of preparing an answer!

People seem fascinated by this, but despite the fact that I work with sharks, I'm afraid of ducks and geese. I was attacked by a Canada goose while I was a little kid.

I'd much rather fight duck-sized horses.

Do you like dolphins?

You could say that I'm not their biggest fan.

Our official blog t-shirt says "I got your dolphins right here, pal".

I live on Cape Cod, MA, and a few of our beaches have been shut down due to sharks. What's the reasoning behind sharks swimming closer and closer to the Atlantic shores every year?

One of the leading theories for this is seal population recovery in New England. More food = more sharks.

Do all these UN-interesting shark shows during shark week piss you off as bad as they do me?

I'll refer you to an interview I did in Wired this week. http://www.wired.com/underwire/2013/08/international-shark-week/

What are some myths about sharks that people believe?

People think of sharks as mindless killing machines, but they actually have larger-than-expected brains for their body size and lots of complex social and ecological behaviors.

Hey David! Thanks for doing an AMA. Other than marine science and sharks, what are you passionate about? What other field might you have gone into?

I feel like most little boys (and a lot of little girls) go through a shark thing or a dinosaur thing. I did both, and chose sharks.

You don't get to be a shark scientist overnight, and you don't get on the boat until you've put in a lot of work. What path did you take to get to where you are now from an education/training/lab standpoint?

I studied biology and marine science at Duke University, and got my Masters in Marine Biology at the College of Charleston.

Is it sustainable/okay to eat shark?

1 in 6 species of sharks, skates, rays or chimeras are Threatened with Extinction, according to the IUCN Red List, with some species suffering reported population declines of over 90% since the 1970's.

However, some countries (the U.S. and Australia in particular) have relatively well-managed shark fisheries.

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The BP Oil Spill has been devastating to marine animals, including some species of sharks. Pollutants and toxins "bioaccumulate", which means that they increase in concentration as you move up the food chain.

Hey David! With so many shark species in decline, is it becoming harder for scientists to find enough live samples to conduct their research?

To some extent. I've been on about 60 sampling trips with my lab here in Miami, and we've caught 0 sharks on 4 of them. It depends on the research question, as some require higher sample sizes than others.

Are there any cultural norms within ocean science? For example, jokes that everyone gets, or common rites of passage?

See the first rule about Fight Club. For good measure, also see the second rule about Fight Club. :)

What are your thoughts on the culling of sharks on Reunion Island? The officials at the island have banned entering the water and are now culling 45 bull sharks and 45 tiger sharks for "scientific purposes". This was caused by a large amount of shark attacks on the island.

Here's an article about it for anyone interested

"Culling" is stupid, ineffective, short-sighted, and environmentally harmful.

Hey David, I'm an undergrad at the University of Miami studying Marine Affairs and Anthropology. I've been interning at the Cape Eleuthera Institute doing shark research for the last two months. Besides applying for an internship with RJ Dunlap what other ways can I get involved with shark conservation in Miami? Thanks, Alice

Hi Alice! I may be biased, but applying to work with our lab is probably your best bet for hands on shark research in the Miami area.

Just out of curiosity, is the research site in Bimini still ongoing?

Yup

Do you have any predictions of what the oceans would be like without sharks? Does climate change put sharks at risk?

The loss of sharks will have a variety of negative ecological consequences. It won't be pretty.

Climate change isn't great for most animals, but sharks face a much, much, much greater threat from commercial overfishing.

What is your favorite beer at WetLab?

Whatever's on special. There are no bad choices for beer at WetLab.

WetLab, for those who don't know, is the on-campus bar at the University of Miami's marine lab. The motto is "providing scientific support services".

Have you ever or would you ever eat shark? What does it taste like?

Yes. It tastes like grouper, a very rich flavor. I don't recommend it because of sustainability issues, but the ones I ate were sacrificed for another scientist's research project, and there was no sense wasting it.

Do sharks only exist to a certain level of depth in the ocean? Also, how come shark isn't as common as a food source as other undersea life?

Sharks can go pretty deep, but not to the absolute bottom of the deepest parts of the ocean.

You did a great job of getting kids to love the ocean and everything about it at Seacamp. Your passion definitely rubbed off on us, and I thank you for that. Charismatic Megafauna was the best class I ever had in my 5 years of Secamp. Sorry this wasn't a question.

(And you're the only reason I know how to do the Cotton-Eyed Joe)

Thanks! FB message me so I know which one of my former students this is!

Hi David, thanks for doing this! In your opinion, when did the trouble with Discovery Channel's Shark Week really start? Do you think the vocal frustration directed towards the current state of Shark-related programming is a recent development, or has it been bubbling under the surface for a while in marine biologist circles?

Thanks again!

Shark Week used to be about science, about inspiring wonder towards the natural world. Some of it, like "Alien Sharks" last night, still is.

What shark do you think is the most badass And why?

Greenland sharks have been found with polar bears, the largest land predator on Earth, in their stomach.

What do you know about the correlation of heightened stress hormones in sharks linked to decreased immune function? I know that increased and prolonged levels of stress in mammals weakens the immune system and am wondering if something similar occurs with sharks.

I'm not trained extensively in stress physiology, but heightened stress hormones have a variety of sublethal effects and I believe that a weakened immune system is among them.

What is the single fact that makes sharks the most amazing animal in the planet?

There were animals recognizable as sharks swimming in the oceans many millions of years before there were dinosaurs. These are ancient vertebrates.

Hi David, I was wondering if you could comment on Tara Reid's recent discussion regarding the generation of whale sharks. Are these the offspring of a kinky dolphin-whale-shark-animal-mammal orgy as Reid implied, or is there an actual scientific evolutionary explanation for the "Whale shark?"

Tara Reid is...not an expert.

Whale sharks are sharks. Fish. Not whales. They're called whale sharks because they're really big.

Hey David,

Outside of this Megalodon chicanery, what was the worst, facepalm-inducing moment you've had when it comes to the media's portrayal of sharks?

Also, if the Megalodon were to face a juvenile Sharktopus, who would win?

"Top 10 Sharkdown" was pretty bad this year. Literally every sentence that wasn't an interview with a scientist had at least one wrong thing in it.

Sharktopus has steel-tipped tentacles, right?

Hi David!

When you lecture or discuss why sharks are important, do you ever discuss why the math on shark attacks doesn't match up to the math? With hundreds of different types sharks, so few that have attacked people, and so many people who DON'T get attacked...

What's a good statistic to share with people who are unreasonably scared of sharks?

Here are some of my favorites:

More people are bitten by OTHER PEOPLE on the New York City Subway each year than by sharks in the whole world.

More people are killed by vending machines, toasters, lawn mowers, and flower pots each year.

How much of your job is spent doing what you imagined you would before you entered the field? In your opinion, is that good or bad?

Also, what is your favorite shark?

My typical day is probably pretty similar to most of your typical days. I answer e-mail and do data entry in Excel. However, I go on about 30-40 shark research trips a year, and those are awesome. If you're with a high school class, community group, etc, you should come RJD.Miami.Edu/participate

Hey David, thanks for the AMA. I lived in the caribbean for a couple of years and was fortunate to encounter nurse sharks and reef sharks diving and snorkeling, on multiple occasions, naturally (not in chummed water or a feeding frenzy), and not once did I feel threatened. Watching shark week yesterday, there was a show about people who had, unfortunately, lost limbs to shark bites. That was it. The whole premise to the show was, people scared who had limbs amputated as a result of a shark attack. I thought shows like that one and the megladon "documentary" are doing way more harm by instituting fear of sharks. What are your thoughts on shows highlighting attacks and instilling fear that there is a large carnivorous shark prowling the oceans?

I'll refer you to a recent interview I gave in Wired http://www.wired.com/underwire/2013/08/international-shark-week/

What are some things that you would suggest to a college student who wishes to follow in your footsteps?

Study math and science, volunteer in labs, read, read, read.

You mentioned that you were recently the victim of a toaster attack. DETAILS.

A certain someone who shall remain nameless didn't clean up the crumbs tray, which almost resulted in a small fire when I tried to make an English muffin.

Would you rather fight a shark sized duck or 100 duck sized sharks?

100 duck sized sharks.

As a shark expert, what was your professional opinion of the movie Sharknado?

Almost as good as "mega shark vs. giant octopus"

With the recent discussions on the decoding of the Mammoth genome, do you think it would be wise to clone and resurrect the species (I ask because you study living creatures and their place in the world) and if so, are there any shark species you would like to see brought back?

I'd prefer that we focus our efforts on not letting current species go extinct. Many extinct animals became extinct because their food source or habitat isn't there anymore, and de-extinction won't fix that. However, I'd love to see a Stellar's Sea Cow (basically a giant manatee), an animal that sailors hunted to extinction in just a few decades.

Hi David, I have been (and would love to go again) shark cage diving with great whites in South Africa: do I risk disturbing the animals in their environment or even worse getting them used to humans when doing so or is it an acceptable practice?

There are dive operators that are extremely responsible.

Have you seen any of:

• mega shark vs giant octopus
• sharktopus
• Shark in venice

If so what did you think?

Loved 'em, particularly mega shark vs. giant octopus.

David - I've really enjoyed your writing and work!

What sites/sources do you read on a daily basis to keep up with sharks, the oceans, etc (Aside from Southern Fried Science, of course)?

This is a shameless plug, but a good friend and I have been working to build a site to try to amplify great writing and conversations about the Oceans and SCUBA in particular - http://www.daily-scuba.com . . .

We'd absolutely love your thoughts on the site sometime . . . we're trying hard to create a great resource for people who love the oceans.

Thanks!

My Google Reader was full of over 200 marine science news sites and blogs, including Daily SCUBA. I know use Feedly, but it ain't the same. I miss my Google Reader.

I have an argument with my marine biologist friend in which she insists that tiger sharks are better than great whites, while I insist the opposite is true. Can I count on you, as an expert in this field, to back me in this noble endeavor, or have you also fallen victim to the propaganda that seeks to dethrone the great white from its rightful place at the top?

Also, thanks for the AMA, sharks are awesome!

I prefer great hammerheads. :)

Ok, everyone! After hundreds of questions and 3 hours, I'm exhausted. You can find me on twitter @WhySharksMatter and I'll answer your questions later. Thanks for having me, reddit!

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I'm skeptical of their effectiveness, but they look awesome.

Hi!

I wanted to know what your least favorite shark/marine animal is

And also, if you had a pet shark what would you name it?

Thank you!

My least favorite shark at the moment is the nurse shark, because one recently slapped my ass so hard with it's tail that I couldn't sit for three days. I also don't particularly care for dolphins, but that's longstanding.

If I had a pet shark, his name would be Steve.

Why do sharks matter?

As top predators, they help keep the ocean ecosystem in balance.

Have you had any scary encounters with sharks? Like one tried to attack you or a student/coworker?

I've never been bitten, and I've interacted with over 3,000 animals both in the water and on the boat. I have hundreds of pictures of sharks, and most are of them swimming away, because that's what they do when they see us.

Do you think that sharks matter in terms of ecosystem stability and resilience? Could you provide some peer reviewed research to support where you think the weight of evidence lies.

Are there some potential benefits to low shark abundance that outweigh the benefits of high shark abundance?

GO!

Here's a good review of shark ecosystem importance that's freely available online: http://www.fmap.ca/ramweb/papers-total/Heithaus_etal_2008.pdf

There are no benefits to low shark abundance that I'm aware of.

Do you think Shark Week does more harm or more good for the study and appreciation of sharks? It realy seems like a double-edged sword to me. On the one hand, raising awareness of ocean science seems important. On the other, 99% of it seems to be scary-voice "documentaries" with lots of slow motion black and white footage and titles like "Sharks: Nature's Most Lethal Killer." And it seems to me that a significant portion of it is just reinforcing peoples misconceptions about sharks in particular, and predators/wildlife in general.

Please see my recent article in Zocalo Public Square about this topic http://www.zocalopublicsquare.org/2013/08/08/dont-gnash-your-teeth-over-shark-week-shark-lovers/ideas/nexus/

Hi David!

It sounds like you're passionate about your job, and I think that's fantastic!

This is kind of a question, kind of not. When I was in grade 7, we watched documentaries on commercial fishing for tuna, and the techniques they use to find tuna (basically, throw a net in an area around dolphins, since dolphins feed off tuna)... bringing the "dolphin friendly" slogan so many tuna companies now write on the can. The trouble is, my seven grade class wrote letters to these "dolphin friendly" companies, asking if they could explain their alternative "dolphin friendly" technique. Their response (from more than one commercial tuna company) was basically "you're in grade 7. You wouldn't understand." Since I read their responses, I have not had a single bite of any sea or lake dwelling creature, because it made me realize how easy it would be to exploit creatures of the sea, (think of all the over-fishing which has been clearly proven) and I wanted no part of it. It's been 18 years!

What information could you give me about this? I feel like the ocean is the forgotten land of animals - even "vegetarians" I know eat fish - and this AMA is the first time I've heard mention of sustainability. Could you point me in the right direction? Also - because then I will have a better retort when people bug me about how I'm weird and picky for not eating fish (in fact, I loved it). And then, maybe I can enjoy seafood again - responsibly and sustainably.

Tl;dr - I think I was a fish in another life. I don't eat fish. I'd like to learn more about sustainability, and also, what effect fishing has on oceanic environments.

Edit: clarity

"Sustainability" is confusing. I like the Monterrey bay Aquarium's seafood watch guide. http://www.montereybayaquarium.org/cr/seafoodwatch.aspx

Does Megalodon exist?

Not anymore. They've been extinct for between 1.5 and 2 million years.

How do you try to invoke change in friends/family members that reply to your conservation posts by saying things like "I love Shark fishing, I just like to hook the big ones."

My family has a lot of fishermen in it, but they've always been ahead of the curve in conservation and catch-and-release. In the hypothetical situation you're describing, I'd explain the ecological importance of sharks and they're threatened status.

Who are your heroes and mentors? Who inspired you to go into science, and who inspires you today?

I liked the ocean long before I knew I could study it professionally. One of my heroes is Eugenie Clark, who I recently met (and, despite being in her late 80's, still hangs out at bars with grad students and is generally awesome).

Hey David, if I cut the bottom of my foot on let's say a shell in the ocean and I bleed, at what distance could a shark pick up on the blood scent? Thanks!

Scent doesn't work at distance. Molecules need to actually touch the chemoreceptors (which means that when you smell something nasty, tiny particles of that something are physically in your nose). But sharks can detect blood in very low concentrations.

What has been your favorite place in the world to dive?

I like Sylvia Earle's answer to this, "anywhere 50 years ago" (i.e. before overfishing.

But the wreck of the Yongala in Australia was my favorite.

What do you think about Nelson the Shark found in the subway a few days ago?

Also, I've always wanted to pet a shark to see how they feel. DETAILS MISTER.

New Yorkers, man. Weird folk.

Sharks are smooth in one direction and feel like sandpaper in the other direction.

What's your hypothesis for the White Shark Cafe?

Also have you tried Hakarl?

The leading hypotheses for the White Shark Cafe (as with just about any aggregation site for animals) deal with reproduction or feeding.

I have not tried Hakarl, but I'm an adventurous eater and would probably try a bite. I expect it's not as tasty as sea turtle.

I was snorkeling in Hawaii and I saw a sea turtle. I was ecstatic at first but then I was terrified because my cousin (who lives in hawaii) told me that wherever there are turtles, there are most likely sharks. How terrified should I have been?

Not at all. There probably were sharks nearby, though (not because there are turtles, but because you're in the ocean).

How many species of sharks do you think that we have still yet to discover?

Scientists have discovered a new species of shark, skate, or ray about every 2 weeks for the last decade or so.

Aside from the recent controversy surrounding the legitimacy of the Megladon documentary on Discovery, how do you think Shark Week has changed public perception on sharks? Do you think Shark Week has helped, hurt, or increased the prominence of sharks in a neutral way?

I'll refer you to an article I wrote on this topic for Zocalo Public Square this week: http://www.zocalopublicsquare.org/2013/08/08/dont-gnash-your-teeth-over-shark-week-shark-lovers/ideas/nexus/

What is you Doctoral Thesis covering? And what led you to decided on that topic? I am applying for doctoral programs in marine biology and am curious how you finally select the project you wanted to cover.

Thank you for doing this AMA, it's great for scientist to reach out the public and interpret the findings in a way everyone can understand rather than the esoteric research journals.

I'm in an interdisciplinary Ph.D. program. I'm studying how sharks impact the food chain, and also how different stakeholder groups (fishers, scientists, conservation activists) perceive how sharks impact the food chain. In other words, Why Sharks Matter

What is the ultimate impact mercury pollution will have on Sharks and other apex, ocean predators?

Can we assume mercury poisoning will lead to erratic behavior for sharks, as it does in other animals?

Mercury does bioaccumulate, moving up the food chain. It may impact shark behavior and physiology, but I don't think this has yet been confirmed.

The biggest threat facing sharks is commercial overfishing, though.

I envy you! I've been intrested/studying sharks since I was 8 and got certified for Scuba at age 12 so that I can dive with sharks. I too live in Miami and have dove all over south Miami and the keys. I've also dove with sharks in Belize. My wife and I are ocean fanatics, she even has an associates in marine biology on top of her bachelors in Business management.

What I would do to have a career in Elasmobranchology

See my blog post on this topic http://www.southernfriedscience.com/?p=8400

What makes sharks so difficult to track and follow? Is it technology-related and if so, are there efforts to improve what tools you as scientists have available?

A fisheries scientist once said that counting fish is like counting trees, except they move around and they're invisible. Radio waves don't transmit through water. Most available technology requires that the shark be at the surface to transmit, which, depending on the species, may not happen that often.

Is the attitude to sharks worse in Florida than other parts of the country?How common are shark attacks along the Florida coast, and how much of a danger are they? Also, is it possible to observe small sharks and other marine life while snorkeling along the coast, or is it better to just stay away from their habitats?

Shark attacks are incredibly rare, even though Florida is the "shark attack capitol of the world". Tens of millions of people go swimming, and like 30-40 a year are bitten. You're more likely to get bitten by another person on the NYC subway, and more likely to be killed by a vending machine, toaster, or lawnmower.

I swim with sharks all the time.

What is one of the scariest facts you have learned about sharks? Also what made you go into this field?

The scariest fact about sharks is that they're one of the most Threatened (in the IUCN Red List sense of the word) group of animals on the planet, with 1 in 6 species Threatened with extinction.

I've always loved sharks, even though I grew up hundreds of miles from the ocean.

CoC! I was raised in Georgetown. Have Great Whites always been present off of the SC coast and it simply seems like a new thing because of advances in tracking or is their presence indeed a new thing?

There's nothing to suggest that great whites weren't always there. I suspect we're just noticing them now because of satellite tracking.

Is there actually a chance the megalodon is still alive?

No.

Hi David! Thanks for doing this! Keep up the good work, like I told you yesterday!! Have you seen or heard from my advisor lately? ;)

E-mail only. He's somewhere in Europe I think.

What's the most intelligent thing Sharks are capable of?

We put GPS satellite tags on some tiger sharks in the Bahamas. They swam over a thousand miles into the middle of the Atlantic ocean...and then came right back to the same beach we tagged them at.

I remember my sister telling me a few years ago about a co-worker who was fishing and ended up being scratched by a sharks tooth on his arm when he was unhooking it. It ended causing extensive nerve damage in his arm and led to a painkiller addiction. Do you know anything about this type of thing? Was it the actual shark tooth that caused it or some sort of bacteria or something that happened to be on its tooth? I've always been curious but she no longer works with him.

I'm obviously not familiar with this specific case, but a sharp object could cause nerve damage if it cut the right place. In general, bacterial infection (from the ocean itself as well as from the shark's mouth) is a bigger problem.

If the Sharknado was real, what would be the best evasive action?

If it was real? Wait, that wasn't a documentary?

I think the lead had the right idea with his strategy of holding a chainsaw above his head. Seemed to work pretty well.

How did you feel about the discovery channel trying to pass off the "megaladon" as a real shark living today?

I'll refer you to my CNN interview on this topic http://thelead.blogs.cnn.com/2013/08/07/scientist-slams-discoverys-shark-week-fake-documentary/

What's the closest you've ever been to getting bitten or injured by a shark?

I got a fishing hook through my hand once. And shark fishing hooks are quite large.

I've never been seriously injured by a shark, but on a recent research trip, a nurse shark slapped my butt and upper thighs so hard that I couldn't sit for three days.

Shark skin is covered in tiny teeth called denticles, and interacting with them leads to what our research team refers to as "SharkBurn". It is quite uncomfortable.

How the hell did that shark got on the subway/

New Yorkers, man.

Do you know Tickle?

I'd rather know Blimp from Voodoo Sharks. But Tickle seems fun. And I loves me some moonshine.

What's your shoe size?

10 1/2, 3E wide. I have weirdly shaped feet.