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>> shark on. >> shark. the very name inspires wonder and fear. vilified as the world's ultimate killing machine. but their bad-boy image is all wrong according to these guys. >> i have not had a single aggressive shark in 35 years of swimming with them on a dale lay basis . >> reporter: he owns a dive shark dive in florida. >> we have 400 billion years of

sharks shaping our ocean's health, and in the last 50 years in my watch we have literally destroyed it. >> one in six of all sharks that have been threatened with extinction. >> dr. neil is also passionate about protecting sharks. he runs the marine conservation lab at university of miami. one of his primary missions, studying sharks in the wild so policymakers can make good conservation decisions based on science. >> i can't really express the value that jim brings to a project like this. >> he relies on jim for his shark savvy. he can get to the sharks. he can figure out what the best conditions are and he can help us design and analyze the study based on behaviors. >> this is wh where you're

likely to find neil when they're in the field. they're getting ready for a five-day expedition off the shores of the bahamas. the goal to, grab and tagged tiger sharks, and "techknow" was invited as part of the mission . >> nothing threatens them. they play an important ecological role. when you remove that large predator there can be this domino affect in the community. >> i join neil and his team in miami as they pack their research gear. >> it's better to be overprepared than under prepared when you'rel in the middle of the ocean dealing with hungry sharks. >> then we boar join the crew. >> this will be your home for

the next weeks. this is the ultimate shark diving boat. >> this is my new home. >> yep. >> after a rough overnight passage through the golf stream we headed towards destination, a special place called tiger beach. it's not a beach, in fact, it's about 20 miles offshore. but it's got plenty of tigers. >> it's highly dominated by sharks, which is really interesting. why would there not be males here? would it be for reproduction? >> everything has to be prepped and ready to go. hen we send out the baits. >> bait in the water. that is nice-looking fish. >> once all eight lines are set we wait for the sharks to bite. sometimes they don't. >> not even crabs eating it? that's insulting. >> and then suddenly a sighting,

and everyone swings into action. >> yes, baby! first tiger of the trip. look at that. >> huge. >> we're fishing with these drum lines and what the drum lines allow the sharks to do. when they're hooked, they swim in these 100-foot large circles. that means they're not fighting and impairing their movement. >> get the line. get the line. get the line. >> that is immense. >> move out of the way. >> get the tail rope. wait, austin, i want to get the tail rope on. can you cut the engine? let's put it on. right after me. guys, it's a female. careful. hold that tail up. get it out of the water. >> they've been trying to pull this thing in for ten minutes.

it is huge. it's the first one of the expedition. everyone is really excited. >> get that head up. first one is always the toughest. okay, it's on. are you ready, she's so big. get that pump in. we insert this pump into the mouth. that's great. it gets to bite down on something and makes them feel better about it, but it's part officially helpinartificially helping them breathe. >> all right, guys, let's go. >> carolyn is an undergrad at the university of new england shark and research lab. she's one of the most crucial jobs using this veterinarian's ultrasound to see if the shark is pregnant. >> on tiger sharks it's tough because they're so massive. we can't get the whole uterus in

one shot. >> this showed that this shark was not pregnant. the next step to plant in acoustic transmitter in the shark. >> this has enough battery power to transmit these ultra sonic signals for seven years while the animal is swimming. then the shark is turned over, and they take detailed measurements. >> tiger sharks, which are predatory sharks are built for many cases ambush. they're built for short bursts of speed. >> when you look at the tiger shark, what can you tell me about it and it's behavior. >> the most distinctive thing you'll notice is the large blunt head. tiger sharks, they don't eat turtles or larger bray like other sharks. their teeth are designed almost

like a can open. >> blood samples are taken before the hook is removed from the mouth and the shark is released. it the whole process takes 20 minutes. >> everybody ready? one, two, three. >> it was spectacular. it swam down to the bottom and leveled off and went off. and jason stayed with it for an unbelievable amount of time while i was gasping for air. >> it's always a learning curve for an animal over one ton and does not want to be on the stern of a boat. >> it will help neil track it's every move in tiger beach. how? by sending a signal to one of these. >> this is the hydrophone. the electronic gear to live to the ping .

it will detect tiger sharks nearby. >> they hope to install 3200 hydrophones located throughout tiger beach. >> the receivers will tell you if it's a shark and allow you to analyze the data and see the patterns in the sharks around an issuingly hydrogen right now the week's work has just begun. another shark is on the platform in one test has everybody guessing. coming up next we're going to find out if she's pregnant. >> we want to hear what you think about these stories. join the conversation by following us on twitter and at al jazeera.com.

[♪ music ] >> it's taking me awhile to develop my sea legs for the water. rough seas make the smallest task a challenge. but before long i'm right at home. of course, i still have to cope with the hazards of the job. >> i always heard that shark skin is rough like stand paper but i found out firsthand how rough it is. but it's all for science. you're trying to unlock the mysteries of one of the world's top redders predators. >> they may be here gestai

ng or giving birth. >> they tagged sharks and 11 were pregnant females. you can see a pup's two eyes and mouth. this place seems particularly important for pregnant tiger sharks. why do you think that is? >> i think what's happening is sharks are spending their 10 to 15 months of gestati on periods in warm waters. >> but pregnant females is hard to come by. meanwhile the crew has another innovation to try out. it's an experiment that he hopes will make research easier on the sharks and the true. >> the reason why i like the platform is because it's bigger. you can walk all around it. the positive thing, and you'll be happy about this,

it's hypertension is on the water. it's not long before the platform is put to the test by 11.5-foot female tiger shark. >> since the shark is dorsal finish up, tissue samples are taken first and then blood is drawn. it will provide a wealth of information, the kind scientists used to only get by sacrificing the shark. >> in the past if you wanted to know what a shark is eating, you cut it open and look in its stomach. now we use fin clips and their blood to learn what they're eating.

>> the shark is flipped over and carolyn begins her ultrasound. >> she's pregnant. >> we got a pregnant one. >> inside this big bloated tiger sharks. it's really exciting, the first female that is pregnant. we need to understand their breeding behaviors, they're doing the surgery to implant the transmitter to get precise details. >> because she's pregnant she's fitted with a second device to track her moments beyond tiger beach. >> the satellite tags are bolting to the fins that have no nerves, no cartilage. we're using medical grade titanium to hold it on. and that makes sure that that tag will fall off eventually.

>> one, two, three. let her go. >> i would like her to go to the side of me. [applause] >> woo, that was awesome. >> the team will follow her wherever she goes on google earth. and of course i had to check out the ultrasound. >> you can see these definitive circles, this is a pup here. this is a pup here. >> tiger sharks have two uteri. this ultrasound shows some of the pups in one of them. >> i'm counting three or four pups in that area. >> there definitely could be more. they come in and out of focus. so it can be really difficult to know. on this one approximately ten

her side. approximately 20 total. >> we'll finish this out. >> time to swing back in action. there was a lot of action over the course of three days. the team had caught a total of 15 sharks. >> i know we call it tiger beach, but it's no beach holid holiday. >> this shark caught on day three turned out to be pure gold for research. she was a female the team had tagged before in october on their last expedition to tiger beach. >> this is our first recaptured shark of the trip. when they found it in october it was pregnant. now we get too find out what happened. >> the ultrasound shows that she is not pregnant now. that's really exciting. that means that we can use the tag data to see where she has gone to give birth. >> how huge that data point for you guys? >> oh my gosh, that data point is to some extent a holy grail for the type of science that we're doing. >> this is a recatcher, i couldn't believe it.

i was just thinking, i hope it's one of our sharks. >> this is why we're here. to try to determine things like their nursery bound. if we protect those important areas we can have a substantial cultivation that would impact the mammal. >> there are over 100 million sharks being killed every year. not just for food, but as by-catch. something needs to be done and you can't conserve an animal unless you know something it. sharks are such mysteries. as big as they are, and as much as we talk about them, we know very little about them. >> and then we see tangible results that can be adopted that will take on conservation measures. >> i think so. as we look at why tiger beach is important, they had hypotheses, but now they have evidence why it's important.

the females go there where it's warmer for gestation, more food, now they're getting solid answers. >> how dangerous is that work? i noticed the wound on your hand. >> i probably should have covered up a bit more. shark skin is incredibly rough. it's basically like sand paper. my shins were all cut up. you can see on my instagram, i was bleeding for science. but it was kind of my own fault because i should have been wea wearing a wetsuit. >> sharks have the reputation for being aggressive animals that are coming to eat us all, but that's not the case. >> going into this piece i had a certain opinion about sharks and the danger of them. what you see is the passion behind these people and evidence when they're out there petting these sharks in the ocean, it convinced me, and now i love them. you can check that out after the break.

>> on tech know, >> what if there was a miracle? >> grace's stem cells are in this box. >> that could save the live of your child... >> we're gonna do whatever we can >> would yo give it a try? >> cell therapy is gonna be the next big advance in medicine >> tech know, every saturday go where science meets humanity. >> this is some of the best driving i've every done, even though i can't see. >> tech know. >> we're here in the vortex. only on al jazeera america. >> hey gays, welcome back. i'm phil torres, you're about to see the final part of this shark

expedition. it was an incredible, intense week of hard work all filled with a passion for sharks and concern of how to help them. >> jim abernathy loves sharks. he wants you to love them, too. that's why he became a pioneer in cage free shark diving, offering people a chance to encounter them up close in the water. >> it's up to us to project them in the way they truly project. we need to protect what we love. dispel. >> i wish we could put a stop to the monster shark thing. almost every animal on the planet attacks and kills more than sharks. we don't have dog week, do we.

in florida we have a dozen fatalities from vending machines. but we don't have vending machine week. he shot most of the underwater video that you're seeing here. >> you were bitten a couple of years ago by a shark. are you ever concerned for your safety? >> no, i'm not concerned at all. the shark that bit me happened when i was tending to the bait. i had hundreds of pounds of bait in rough seas. it bit my right arm and then released me. sharks don't eat people. the only reason they bite someone is because of maken identifymistaken identify. >> oh my gosh. >> they're feeding on turtles. >> his crew are all divers who run the water and take care of its passengers. including us.

they all want to spread the same tiger shark love. >> we name these guys. emily, emma, stephanie, julia, and they come by in the water and they want us to rub their little noses. i wish people could appreciate them for what they are. >> a smile crosses my face as soon as i see them. nothing else matters. >> the last week we had not seen julia for a while. she showed up on the third or fourth day. yay, she's here. it's embarrassing now that i think about it. >> your crew gives affection to sharks on a daily basis. >> the reason why we started doing that, years ago i was trying to remove the hooks from the sharks without pulling them out of the water. and i quickly realized that sharks like affection. i could give a shark a head massage, so to speak, and then eventually when it was very trusting i could pull it in close to my face where i see the hook right in its jaw and simply

pull it out. it doesn't take very long to figure out that neil really loves sharks. he's answering the questions that the non-profits need in order to put the right rules into place where it can be very impactful for the future of sharks worldwide. >> they hope that the research at tiger beach will help answer some of those questions. >> do you have any day on the shark recaptured? >> that was the first thing that i looked at. when you look at her data, what does that tell you? she tuck around. >> she was there from when we tagged her to now. and we know that sometime between when we last saw her and now she gave birth. >> if she was there the whole time, is it possible that she gave birth at tiger beach? >> there is some days that there is a gap in the data by a handful of days.

the question is did she move off to give birth and then come back to tiger beach. i think if i play around with the data i can get some recaptures you can see the puzzle pieces come together. >> when you're processing it, it looks like that's when the research happens, that it swims away and it doesn't end there. >> definitely not. you're just seeing the precursor. while we're having this conversation the sharks are doing my work for me and collecting data. >> you know, it brought me back to my days in the rain forest. i just love that feeling of working with a team and working hard and in these tough physical conditions. i was amazed. there were two young women there who were juniors in college and out there doing this work. i'm always amazed by science careers. a lot of people out there don't quite realize what they could be doing as their summer job when they're 20. >> that was some incredible footage. how did we get that?

what was the set up? >> it was awesome. we were shooting above water. we were shooting in the water. jim abernathy had this great set up in there. just the great perspectives they were getting. and the fact that we caught and processed 15 sharks. each time the cameras focused on the different aspect of the operation. >> i guess that shark fin was not on the menu? >> no, they're quite against it. soup. i was very thankful to have a sea sickness. medicine that surprisingly i did all right. >> it was a wonderful journey that you were able to take us all on. thanthank you for take us with you. >> really, i hope it affected you as much as it affected me and my view on sharks is completely different. we'll see you next week here in "techknow."

>> go to www.aljazeera.com www.aljazeera.com/techknow. follow our contributers on facebook, google plus and more. >> this is al jazeera america. live from new york city. i'm tony harris with a look at today's top stories. president obama vows justice will be served. and americans will not be intim dated after the islamic state group kills another u.s. journalist. and the seven steps required to remove russian troops from the