1 00:00:04,400 --> 00:00:08,840 Sharks - nature's perfect solution to an underwater life. 2 00:00:11,000 --> 00:00:14,200 They've been swimming in the oceans for over 400 million years... 3 00:00:15,560 --> 00:00:17,320 ..and, as top predators, 4 00:00:17,320 --> 00:00:20,160 play a vital role in keeping our seas healthy 5 00:00:20,160 --> 00:00:21,840 and productive. 6 00:00:24,240 --> 00:00:26,760 But they're coming under increasing pressure, 7 00:00:26,760 --> 00:00:29,560 millions are hunted and killed every year. 8 00:00:32,080 --> 00:00:34,080 Never have sharks needed friends 9 00:00:34,080 --> 00:00:35,920 more than they do today. 10 00:00:40,200 --> 00:00:43,600 For three weeks, I've been in the Bahamas for Blue Planet Live. 11 00:00:45,600 --> 00:00:47,240 Watching, 12 00:00:47,240 --> 00:00:48,920 monitoring, 13 00:00:48,920 --> 00:00:53,640 and diving with one of the richest shark populations on the planet. 14 00:00:56,600 --> 00:00:59,640 I want to reveal why sharks are thriving here 15 00:00:59,640 --> 00:01:02,240 and find out if there are lessons to be learned 16 00:01:02,240 --> 00:01:05,120 from these crystal clear waters 17 00:01:05,120 --> 00:01:08,960 that could help secure their future elsewhere around the world. 18 00:01:45,960 --> 00:01:50,240 Our blue planet is home to more than a thousand species of shark... 19 00:01:51,600 --> 00:01:53,360 ..and their cousins, the rays. 20 00:01:58,160 --> 00:02:00,560 They come in a myriad of shapes... 21 00:02:05,000 --> 00:02:06,680 ..and sizes... 22 00:02:07,920 --> 00:02:10,120 ..and are found across all of our oceans... 23 00:02:11,520 --> 00:02:12,720 ..from the tropics... 24 00:02:13,800 --> 00:02:15,680 ..to the Arctic... 25 00:02:15,680 --> 00:02:17,680 ..and into the deep abyss. 26 00:02:22,520 --> 00:02:26,160 There are a few places where the number and diversity of sharks 27 00:02:26,160 --> 00:02:27,800 is unparalleled. 28 00:02:30,480 --> 00:02:33,080 The Bahamas is one of them, 29 00:02:33,080 --> 00:02:36,640 earning it the title of shark diving capital of the world. 30 00:02:41,240 --> 00:02:46,200 700 islands are scattered over 84,000 square miles of ocean. 31 00:02:51,400 --> 00:02:53,800 This location is unique - 32 00:02:53,800 --> 00:02:56,040 perched on the edge of deep water, 33 00:02:56,040 --> 00:02:59,960 where the seabed plunges to a depth of 4,000 metres. 34 00:03:03,160 --> 00:03:07,000 The meeting of shallow water and deep, open ocean 35 00:03:07,000 --> 00:03:09,440 leads to a profusion of life. 36 00:03:15,920 --> 00:03:19,240 In winter, the resident Caribbean reef sharks 37 00:03:19,240 --> 00:03:20,800 and bull sharks 38 00:03:20,800 --> 00:03:23,480 are joined by visitors, 39 00:03:23,480 --> 00:03:28,120 bolstering the shark and ray population to 78 species. 40 00:03:42,760 --> 00:03:47,920 In 2011, the Bahamas were declared a shark sanctuary, 41 00:03:47,920 --> 00:03:52,160 making it illegal to fish for or kill any species of shark. 42 00:04:00,440 --> 00:04:03,800 These protected waters offer me a unique chance 43 00:04:03,800 --> 00:04:06,080 to get close to these amazing top predators... 44 00:04:08,240 --> 00:04:10,600 ..and to see first-hand what it takes 45 00:04:10,600 --> 00:04:14,320 to have a healthy, thriving population of sharks. 46 00:04:21,200 --> 00:04:24,000 Within seconds of coming down here, 47 00:04:24,000 --> 00:04:27,800 I'm greeted with one of the most dazzling displays 48 00:04:27,800 --> 00:04:29,600 you'll ever see underwater. 49 00:04:44,320 --> 00:04:47,160 There's probably two or three different sort of shark 50 00:04:47,160 --> 00:04:50,400 at this location, but the dominant kind 51 00:04:50,400 --> 00:04:53,680 is going to be the Caribbean reef shark. 52 00:04:53,680 --> 00:04:58,120 And I can already see at least 20 of them here in the water around us. 53 00:05:00,560 --> 00:05:03,640 I guess the first question that people would ask would be, 54 00:05:03,640 --> 00:05:06,440 isn't it dangerous, isn't it risky to be surrounded 55 00:05:06,440 --> 00:05:08,720 by this many apex predators? 56 00:05:08,720 --> 00:05:10,400 And I have to say, 57 00:05:10,400 --> 00:05:13,240 I feel just as comfortable being in here, 58 00:05:13,240 --> 00:05:16,320 surrounded by all these extraordinary animals, 59 00:05:16,320 --> 00:05:19,600 as I would do going for a walk with a pack of poodles. 60 00:05:23,120 --> 00:05:28,000 These animals are so good at sensing their environment, 61 00:05:28,000 --> 00:05:30,600 they know what's prey in the water around them, 62 00:05:30,600 --> 00:05:32,680 and it's not us. 63 00:05:32,680 --> 00:05:35,600 They may well swim in close but at the last second, 64 00:05:35,600 --> 00:05:37,440 they just bank away. 65 00:05:37,440 --> 00:05:39,760 They could not be less interested, 66 00:05:39,760 --> 00:05:43,400 and the statistics about sharks prove that's true. 67 00:05:43,400 --> 00:05:48,160 Around the world, you're more likely to be killed taking a selfie 68 00:05:48,160 --> 00:05:51,040 than you are to be killed by a shark. 69 00:05:52,680 --> 00:05:55,000 In fact, statistically speaking, 70 00:05:55,000 --> 00:05:59,680 the chance of being killed by a cow, a deer or even a vending machine 71 00:05:59,680 --> 00:06:02,600 is higher than the risk posed by one of these. 72 00:06:08,320 --> 00:06:12,360 Sadly, this abundance of sharks is not typical 73 00:06:12,360 --> 00:06:14,480 across all of our oceans. 74 00:06:15,920 --> 00:06:19,280 This is not a sight that you get to see just anywhere. 75 00:06:19,280 --> 00:06:22,440 So, around the world, we human beings are taking 76 00:06:22,440 --> 00:06:26,040 at least 100 million sharks from the world's oceans 77 00:06:26,040 --> 00:06:27,480 every single year. 78 00:06:30,160 --> 00:06:35,080 In some places, sharks have declined by over 90%. 79 00:06:35,080 --> 00:06:38,640 And in the time it'll take for you to watch this programme, 80 00:06:38,640 --> 00:06:41,600 over 11,500 will be killed. 81 00:06:43,920 --> 00:06:46,680 It's a number that simply cannot be sustained. 82 00:06:46,680 --> 00:06:48,520 If it carries on like this, 83 00:06:48,520 --> 00:06:51,480 then our children will not have the opportunity 84 00:06:51,480 --> 00:06:53,480 to dive in seas like this, 85 00:06:53,480 --> 00:06:56,120 surrounded by these stunning predators. 86 00:06:58,400 --> 00:07:03,240 The Bahamas isn't the only place to offer protection to sharks. 87 00:07:03,240 --> 00:07:07,720 Today, a total of 17 sanctuaries have been created around the world, 88 00:07:07,720 --> 00:07:10,960 covering over 7.5 million square miles. 89 00:07:13,400 --> 00:07:17,080 But this still amounts to only 5% of our oceans. 90 00:07:20,080 --> 00:07:22,520 Sharks need more help, 91 00:07:22,520 --> 00:07:24,600 and if we don't give it to them, 92 00:07:24,600 --> 00:07:27,320 much of the life in our oceans will suffer. 93 00:07:29,400 --> 00:07:31,080 As apex predators, 94 00:07:31,080 --> 00:07:33,640 they remove any sick or injured animals, 95 00:07:33,640 --> 00:07:35,600 keeping fish stocks healthy. 96 00:07:37,160 --> 00:07:38,960 Animals below them in the food chain 97 00:07:38,960 --> 00:07:40,840 are kept in check. 98 00:07:40,840 --> 00:07:45,040 And removing sharks would unbalance whole ecosystems. 99 00:07:47,680 --> 00:07:51,280 Over 3 billion people depend on the ocean for their livelihoods. 100 00:07:53,280 --> 00:07:56,320 It's essential we protect sharks for our sake 101 00:07:56,320 --> 00:07:57,680 as well as theirs. 102 00:07:59,080 --> 00:08:03,760 And a vital step towards this is combatting the reputation of fear 103 00:08:03,760 --> 00:08:05,840 that many sharks still hold. 104 00:08:18,640 --> 00:08:21,120 I always had a passion for the ocean. 105 00:08:22,440 --> 00:08:24,600 I fell in love with scuba diving. 106 00:08:24,600 --> 00:08:26,720 I fell in love with everything. 107 00:08:26,720 --> 00:08:29,840 It was a calling, I think. 108 00:08:37,640 --> 00:08:42,160 Cristina Zenato left her homeland of Italy over 20 years ago, 109 00:08:42,160 --> 00:08:43,760 heading for the Bahamas. 110 00:08:46,840 --> 00:08:50,440 Ever since, she's become an advocate for sharks. 111 00:09:00,680 --> 00:09:03,280 And two decades of diving at one site, 112 00:09:03,280 --> 00:09:05,560 off the island of Grand Bahama, 113 00:09:05,560 --> 00:09:09,360 has convinced her that these animals are a long way from being 114 00:09:09,360 --> 00:09:10,800 mindless killers. 115 00:09:14,400 --> 00:09:18,120 Cristina is known locally as the Shark Dancer... 116 00:09:21,960 --> 00:09:24,400 ..and this is her stage. 117 00:09:26,920 --> 00:09:31,280 I love that there is a busy silence. 118 00:09:39,080 --> 00:09:42,720 It is the most peaceful and calming moment of my day. 119 00:09:48,640 --> 00:09:51,600 My babies are Caribbean reef sharks. 120 00:09:54,680 --> 00:09:57,320 I love watching their behaviours 121 00:09:57,320 --> 00:09:59,120 and their interactions. 122 00:10:02,200 --> 00:10:04,360 They appear to me as different 123 00:10:04,360 --> 00:10:07,280 as any other human being that I encounter. 124 00:10:08,880 --> 00:10:10,960 Some of them are more dominant. 125 00:10:12,160 --> 00:10:14,000 Some of them are shy. 126 00:10:15,880 --> 00:10:20,440 And some seemingly seek out a closer encounter with Cristina. 127 00:10:23,200 --> 00:10:27,440 The first time that shark settled in my lap... 128 00:10:29,440 --> 00:10:31,640 ..and every time, she settles in my lap, 129 00:10:31,640 --> 00:10:33,880 and I feel her weight over my legs, 130 00:10:33,880 --> 00:10:37,120 that is the most amazing feeling... 131 00:10:38,320 --> 00:10:41,800 ..and there's nothing, to this day, that beats that. 132 00:10:46,400 --> 00:10:49,320 You can feel everything about the shark. 133 00:10:49,320 --> 00:10:53,280 You can feel that it's a living, breathing creature 134 00:10:53,280 --> 00:10:56,400 that is aware of her surroundings, 135 00:10:56,400 --> 00:10:59,680 that is aware of what I am doing to her, 136 00:10:59,680 --> 00:11:02,400 that is aware of my touch. 137 00:11:02,400 --> 00:11:06,160 And the suit might actually have a nice feeling to their skin. 138 00:11:08,520 --> 00:11:11,240 These sharks are 8ft long. 139 00:11:11,240 --> 00:11:14,200 I could never force an animal of that size 140 00:11:14,200 --> 00:11:16,520 to do anything or to sit anywhere. 141 00:11:19,040 --> 00:11:21,160 It's their decision to come in, 142 00:11:21,160 --> 00:11:23,440 it's their decision to stay, 143 00:11:23,440 --> 00:11:25,680 it's their decision to go. 144 00:11:30,160 --> 00:11:35,560 There is a total disconnect from humans to sharks. 145 00:11:37,840 --> 00:11:41,680 We can swim in the ocean with sharks in a way that you could never 146 00:11:41,680 --> 00:11:45,120 walk around on the snow with a polar bear following you. 147 00:11:47,840 --> 00:11:51,080 We have to make that connection with the sharks, 148 00:11:51,080 --> 00:11:53,960 understanding they are way, way less dangerous 149 00:11:53,960 --> 00:11:55,800 than many creatures out there. 150 00:11:59,400 --> 00:12:02,480 Cristina's unique relationship with sharks 151 00:12:02,480 --> 00:12:05,480 allows her to do something quite extraordinary. 152 00:12:14,160 --> 00:12:18,200 She can take out fishing hooks that are caught in their mouths. 153 00:12:26,600 --> 00:12:31,280 Over the years, she's removed more than 300 hooks. 154 00:12:41,840 --> 00:12:43,400 We must change our ways, 155 00:12:43,400 --> 00:12:45,520 because we need to protect the oceans 156 00:12:45,520 --> 00:12:47,720 and we need to protect the sharks. 157 00:12:47,720 --> 00:12:50,040 And when you reach that message, 158 00:12:50,040 --> 00:12:51,600 then you have a victory. 159 00:12:58,120 --> 00:13:01,560 A greater understanding of these misunderstood creatures 160 00:13:01,560 --> 00:13:04,000 can undoubtedly help sharks. 161 00:13:07,880 --> 00:13:11,480 And with such a diverse and healthy population on its doorstep... 162 00:13:14,520 --> 00:13:19,200 ..the Bahamas has long been at the forefront of global shark research. 163 00:13:22,040 --> 00:13:24,080 The Bimini Biological Field Station, 164 00:13:24,080 --> 00:13:26,000 or Shark Lab, 165 00:13:26,000 --> 00:13:29,120 has been increasing our knowledge of sharks and rays 166 00:13:29,120 --> 00:13:31,000 for the last 29 years. 167 00:13:37,920 --> 00:13:40,160 Heading this institute is Matt Smukall, 168 00:13:40,160 --> 00:13:42,400 who's had a passion for the marine world 169 00:13:42,400 --> 00:13:43,840 for as long as he can remember. 170 00:13:46,200 --> 00:13:49,080 MATT: My first memories were snorkelling in the Florida Keys. 171 00:13:49,080 --> 00:13:52,480 Growing up, I always had an affinity and a connection with, you know, 172 00:13:52,480 --> 00:13:55,760 spending pretty much every weekend and all summer in the ocean. 173 00:13:55,760 --> 00:13:58,040 My favourite group of animals are the sharks. 174 00:13:58,040 --> 00:14:00,360 That's what originally brought me to the Shark Lab, 175 00:14:00,360 --> 00:14:02,320 that's what makes me enjoy waking up every day 176 00:14:02,320 --> 00:14:03,520 and doing this job. 177 00:14:04,960 --> 00:14:07,800 The Bimini Shark Lab started in 1990. 178 00:14:07,800 --> 00:14:11,040 Right now at the Shark Lab, we're studying everything from 179 00:14:11,040 --> 00:14:13,720 southern stingrays to bull sharks, tiger sharks, 180 00:14:13,720 --> 00:14:15,720 lemon sharks, hammerheads, 181 00:14:15,720 --> 00:14:19,640 but we take it from a very ecosystem-driven model, 182 00:14:19,640 --> 00:14:21,200 where we want to understand 183 00:14:21,200 --> 00:14:23,400 everything that's going on around Bimini 184 00:14:23,400 --> 00:14:25,440 and how that's impacting these big sharks. 185 00:14:29,720 --> 00:14:32,480 One of the biggest and most impressive species, 186 00:14:32,480 --> 00:14:35,400 and the focus for a number of Shark Lab studies, 187 00:14:35,400 --> 00:14:39,440 can be found a stone's throw from the heart of a busy marina. 188 00:14:46,360 --> 00:14:48,680 These are bull sharks... 189 00:14:50,120 --> 00:14:53,280 ..drawn in by the scraps discarded from fishing boats. 190 00:14:56,760 --> 00:14:59,360 They spend much of their lives in murky estuaries... 191 00:15:01,200 --> 00:15:04,440 ..so this clear water gives me a unique opportunity 192 00:15:04,440 --> 00:15:08,160 to see them up close, and Matt a chance to learn more 193 00:15:08,160 --> 00:15:11,200 about this little understood species of shark. 194 00:15:13,760 --> 00:15:16,200 I'm here on the bottom of the harbour 195 00:15:16,200 --> 00:15:19,360 and, as you can probably see, 196 00:15:19,360 --> 00:15:23,040 I'm absolutely surrounded by bull sharks. 197 00:15:28,840 --> 00:15:33,080 This is an opportunist that has a very wide array 198 00:15:33,080 --> 00:15:35,480 of different kinds of prey, 199 00:15:35,480 --> 00:15:40,440 so they'll feed on fish, on rays, on birds at the surface, 200 00:15:40,440 --> 00:15:45,480 on dolphins, they'll even bite through the shells of turtles. 201 00:15:46,920 --> 00:15:50,200 Now, all the sharks that I'm seeing around me at the moment 202 00:15:50,200 --> 00:15:53,000 are females, I haven't seen a single male. 203 00:15:54,000 --> 00:15:57,440 And they're quite big in the belly. 204 00:16:00,320 --> 00:16:02,880 Why the warm waters of the Bahamas attract 205 00:16:02,880 --> 00:16:05,400 these large, slightly rotund females 206 00:16:05,400 --> 00:16:07,320 has long been a mystery. 207 00:16:07,320 --> 00:16:11,040 One Matt and his team from Shark Lab are hoping to solve. 208 00:16:12,120 --> 00:16:14,920 But to do that, they first have to catch one. 209 00:16:17,280 --> 00:16:20,840 To go ahead and catch, say, a big female bull shark, 210 00:16:20,840 --> 00:16:23,760 what we'll do is drop a baited hook, throw it right in, 211 00:16:23,760 --> 00:16:26,320 and they pretty quickly will normally take the hook. 212 00:16:32,080 --> 00:16:34,280 All right. On, on, on. 213 00:16:34,280 --> 00:16:36,480 Hooking the bull shark is the easy part. 214 00:16:36,480 --> 00:16:40,080 As soon as they start running around with the balls and the rope, 215 00:16:40,080 --> 00:16:43,120 this is a bit of a dance between the person bringing it in 216 00:16:43,120 --> 00:16:44,400 and the shark. 217 00:16:55,960 --> 00:16:57,600 We have to be very careful 218 00:16:57,600 --> 00:17:00,640 cos they are not expecting to be caught and handled by humans. 219 00:17:03,400 --> 00:17:05,040 In order to help, number one, 220 00:17:05,040 --> 00:17:07,640 for human safety but also for shark safety, 221 00:17:07,640 --> 00:17:09,960 we'll put a tail rope on. 222 00:17:09,960 --> 00:17:13,040 That helps to secure the shark to the boat. 223 00:17:13,040 --> 00:17:14,640 Quick! Quick! 224 00:17:15,640 --> 00:17:17,960 INDISTINCT CHATTER 225 00:17:19,760 --> 00:17:21,960 With the shark safely harnessed and calm, 226 00:17:21,960 --> 00:17:24,200 the team can take the measurements 227 00:17:24,200 --> 00:17:26,280 and assess the shark's condition. 228 00:17:28,480 --> 00:17:30,520 And one of the most crucial jobs 229 00:17:30,520 --> 00:17:32,920 is to find out her reproductive state... 230 00:17:34,960 --> 00:17:36,560 ..using a very familiar method. 231 00:17:38,800 --> 00:17:40,200 Ultrasound. 232 00:17:43,280 --> 00:17:46,000 I think there's something right there. 233 00:17:49,480 --> 00:17:51,600 You can see it moving slightly there. 234 00:17:51,600 --> 00:17:52,840 That looks like the pup. 235 00:17:56,520 --> 00:18:01,080 Over 50% of the females that we catch are actually pregnant. 236 00:18:02,080 --> 00:18:03,800 They have paired uterus, 237 00:18:03,800 --> 00:18:05,400 so we check both sides. 238 00:18:05,400 --> 00:18:06,880 And we're going to try to count 239 00:18:06,880 --> 00:18:08,480 the number of pups that we can see, 240 00:18:08,480 --> 00:18:10,320 the size of pups in both sides, 241 00:18:10,320 --> 00:18:13,800 to get a better understanding of her offspring litter. 242 00:18:15,560 --> 00:18:19,840 After ten months, bull sharks give birth to up to 13 pups. 243 00:18:21,680 --> 00:18:24,360 These fully-formed pint-size sharks 244 00:18:24,360 --> 00:18:27,040 are then left to fend for themselves. 245 00:18:29,960 --> 00:18:31,880 Now that we've confirmed she's pregnant, 246 00:18:31,880 --> 00:18:34,480 we're going to go ahead and let her go on her way. 247 00:18:34,480 --> 00:18:37,120 Give her a push. 248 00:18:37,120 --> 00:18:38,680 All right, nice job. 249 00:18:40,600 --> 00:18:42,120 At the end of the procedure, 250 00:18:42,120 --> 00:18:44,680 it's great to be able to give that shark a push. 251 00:18:44,680 --> 00:18:46,640 We're blessed here with beautiful, clear water 252 00:18:46,640 --> 00:18:48,680 and we can always observe the shark, 253 00:18:48,680 --> 00:18:51,240 basically follow her to make sure that she's swimming strong 254 00:18:51,240 --> 00:18:53,000 and that she's doing well. 255 00:18:54,400 --> 00:18:57,240 And it's not just the visiting bull sharks 256 00:18:57,240 --> 00:18:59,080 who are carrying the next generation. 257 00:19:03,960 --> 00:19:06,160 Many other species found in the Bahamas 258 00:19:06,160 --> 00:19:07,760 are also pregnant. 259 00:19:13,520 --> 00:19:17,360 It's thought that the warm waters and rich feeding grounds here 260 00:19:17,360 --> 00:19:21,200 help raise the shark's metabolism and speed up gestation. 261 00:19:31,360 --> 00:19:33,600 MATT: We know a lot about sharks but there's so much more 262 00:19:33,600 --> 00:19:35,560 that we still need to understand. 263 00:19:35,560 --> 00:19:39,080 We still don't even know some of the basic reproductive biology, 264 00:19:39,080 --> 00:19:40,800 some of their life history things, 265 00:19:40,800 --> 00:19:43,320 and these are all very important for conservation. 266 00:19:43,320 --> 00:19:45,800 This is what's really going to help us manage 267 00:19:45,800 --> 00:19:47,400 the next generation of sharks. 268 00:19:49,840 --> 00:19:52,520 And it's managing this next generation 269 00:19:52,520 --> 00:19:55,560 and the habitats that are essential to their survival 270 00:19:55,560 --> 00:19:59,360 that's vital to maintaining a healthy population of sharks. 271 00:20:15,040 --> 00:20:19,440 This tangled mass of roots is the mangroves. 272 00:20:19,440 --> 00:20:21,920 It's an environment that changes constantly 273 00:20:21,920 --> 00:20:23,920 with the tides throughout the day. 274 00:20:23,920 --> 00:20:28,240 And provides the perfect spot for baby marine animals 275 00:20:28,240 --> 00:20:29,640 to hide out in. 276 00:20:31,520 --> 00:20:34,960 I'm joining Clemency White from Bimini Shark Lab 277 00:20:34,960 --> 00:20:38,160 to see how these mangroves are key to the success of sharks 278 00:20:38,160 --> 00:20:39,480 in the Bahamas. 279 00:20:43,040 --> 00:20:44,840 Whoa! Look at that! 280 00:20:45,920 --> 00:20:47,920 Yep, they're all waiting for us. 281 00:20:47,920 --> 00:20:49,320 Baby sharks! 282 00:20:50,720 --> 00:20:53,040 That's absolutely incredible. 283 00:20:58,280 --> 00:21:00,400 These are lemon sharks. 284 00:21:00,400 --> 00:21:03,560 And they've been studied by Clemency and her fellow researchers 285 00:21:03,560 --> 00:21:05,000 for over 30 years. 286 00:21:07,640 --> 00:21:09,360 It looks like they want to be fed. 287 00:21:09,360 --> 00:21:11,480 Yeah, we actually have a little bit of squid 288 00:21:11,480 --> 00:21:13,080 if you want to give it a go. 289 00:21:13,080 --> 00:21:15,160 I...I would genuinely love to. 290 00:21:17,960 --> 00:21:20,680 So, Clemency, how old are the sharks we're looking at here? 291 00:21:20,680 --> 00:21:23,120 Most of these sharks are in their first few years of life. 292 00:21:23,120 --> 00:21:25,480 So the majority of them will be maybe two or three years old. 293 00:21:25,480 --> 00:21:27,120 And some of those larger sharks you can see 294 00:21:27,120 --> 00:21:28,760 are maybe four or five. 295 00:21:28,760 --> 00:21:30,000 So this is a refuge. 296 00:21:30,000 --> 00:21:32,200 This is an area that's pretty much only accessible 297 00:21:32,200 --> 00:21:33,800 to these guys at high tide. 298 00:21:33,800 --> 00:21:36,160 So that small, narrow walkway that we walked in, 299 00:21:36,160 --> 00:21:37,720 bigger sharks can't use that. 300 00:21:37,720 --> 00:21:39,760 What sort of things are they taking shelter from? 301 00:21:39,760 --> 00:21:42,200 The biggest predator of juvenile lemon sharks is actually 302 00:21:42,200 --> 00:21:44,200 lemon sharks themselves, adult lemon sharks. 303 00:21:44,200 --> 00:21:46,880 So they're cannibalistic? Yes, they are cannibalistic. 304 00:21:46,880 --> 00:21:50,080 And also other large sharks, so maybe bull sharks, 305 00:21:50,080 --> 00:21:52,720 other species like that. 306 00:21:52,720 --> 00:21:55,320 So this genuinely is a nursery, 307 00:21:55,320 --> 00:21:58,400 it's a place where the youngsters are safe from other... 308 00:21:58,400 --> 00:22:01,080 Oh! That went right between my legs. 309 00:22:01,080 --> 00:22:04,480 Yeah. I should be wearing a cricket box or something. Um... 310 00:22:04,480 --> 00:22:05,720 Are you OK? 311 00:22:05,720 --> 00:22:07,600 THEY LAUGH No! 312 00:22:07,600 --> 00:22:09,600 Seriously, they're all making a beeline 313 00:22:09,600 --> 00:22:12,360 straight between my legs. 314 00:22:12,360 --> 00:22:13,880 This would be a disaster if 315 00:22:13,880 --> 00:22:15,880 all the things I've done in my life 316 00:22:15,880 --> 00:22:18,360 and I was to get savaged in the goolies by a baby shark. 317 00:22:18,360 --> 00:22:20,120 Well, they must like you. 318 00:22:21,760 --> 00:22:23,560 That one there's a decent size. 319 00:22:23,560 --> 00:22:26,840 Yeah, so they'll be pretty loyal to the mangrove that they were born in 320 00:22:26,840 --> 00:22:29,480 until they're about 13 years old, when they sexually mature. 321 00:22:29,480 --> 00:22:31,880 Then they'll also come back to give birth here as adults. 322 00:22:31,880 --> 00:22:33,400 So they really rely on those mangroves 323 00:22:33,400 --> 00:22:34,920 for their entire life cycle. 324 00:22:34,920 --> 00:22:37,640 What are the main threats to mangroves in the Bahamas? 325 00:22:37,640 --> 00:22:39,880 So, a lot of places, even in Bimini, 326 00:22:39,880 --> 00:22:43,120 we see the mangroves are being removed to facilitate bigger hotels, 327 00:22:43,120 --> 00:22:45,560 bigger resorts, and that in itself means 328 00:22:45,560 --> 00:22:47,720 that these pups will still be born in the same place, 329 00:22:47,720 --> 00:22:49,520 they'll still be using the same areas, 330 00:22:49,520 --> 00:22:52,280 but they won't have that same security from the larger fish. 331 00:22:52,280 --> 00:22:56,080 So, lose the mangroves and you lose the lemon sharks? Yep. 332 00:22:59,560 --> 00:23:03,000 It may not look like any other nursery you've seen before, 333 00:23:03,000 --> 00:23:05,840 but you can see how vital this environment is 334 00:23:05,840 --> 00:23:09,920 to these rather wonderful and surprisingly cute animals. Mm-hm. 335 00:23:18,280 --> 00:23:22,120 All over the world, baby sharks and rays seek refuge 336 00:23:22,120 --> 00:23:24,720 in mangroves, seagrass and estuaries. 337 00:23:31,240 --> 00:23:33,120 Throughout their lives, 338 00:23:33,120 --> 00:23:36,040 sharks need a whole variety of ocean habitats... 339 00:23:38,240 --> 00:23:40,520 ..and protecting these is essential 340 00:23:40,520 --> 00:23:42,960 if shark numbers are to bounce back. 341 00:23:55,440 --> 00:23:58,760 Most sharks take many years to reach sexual maturity. 342 00:24:00,560 --> 00:24:04,720 Female great white sharks need a whopping 33 years 343 00:24:04,720 --> 00:24:06,560 before they can breed. 344 00:24:08,240 --> 00:24:12,520 This, combined with their tendency to produce just a few offspring, 345 00:24:12,520 --> 00:24:16,760 means that shark populations are extremely vulnerable to overfishing. 346 00:24:40,600 --> 00:24:44,760 Right now, sharks are being killed at a staggering rate. 347 00:24:54,960 --> 00:24:56,960 They're deliberately caught for food. 348 00:24:59,080 --> 00:25:02,240 And accidentally caught in nets or long lines 349 00:25:02,240 --> 00:25:04,000 set for other species. 350 00:25:10,200 --> 00:25:14,040 They're also harvested in their millions for their fins, 351 00:25:14,040 --> 00:25:17,800 to make shark fin soup - 352 00:25:17,800 --> 00:25:23,560 a delicacy that's seen shark fins sell for $650 a kilo... 353 00:25:29,440 --> 00:25:32,720 ..fuelling a cruel, wasteful trade, 354 00:25:32,720 --> 00:25:36,360 which sees the rest of the shark being thrown back into the sea... 355 00:25:38,000 --> 00:25:39,640 ..often still alive. 356 00:25:43,920 --> 00:25:47,320 A third of all shark species are now threated with extinction. 357 00:25:49,400 --> 00:25:53,040 And this is being driven by human activities. 358 00:26:08,560 --> 00:26:10,520 But all is not yet lost. 359 00:26:11,520 --> 00:26:13,280 There is hope. 360 00:26:13,280 --> 00:26:15,760 And it comes from the fact that these sharks 361 00:26:15,760 --> 00:26:19,240 can be worth more alive than dead. 362 00:26:34,720 --> 00:26:37,520 I'm heading 12 miles north of Grand Bahama 363 00:26:37,520 --> 00:26:39,760 to a site of global importance. 364 00:26:50,960 --> 00:26:54,800 This could well be the best shark dive in the whole world. 365 00:26:56,440 --> 00:27:00,640 And what happens here is key to securing the future of sharks 366 00:27:00,640 --> 00:27:02,360 right across the world. 367 00:27:04,920 --> 00:27:09,200 Whoa! Great hammerhead! Amazing. 368 00:27:09,200 --> 00:27:14,080 Look at that. Powering straight in. 369 00:27:14,080 --> 00:27:15,920 That is just extraordinary. 370 00:27:17,840 --> 00:27:21,360 Drawn to the warm, productive waters, 371 00:27:21,360 --> 00:27:25,120 this is also the best place in the world to see tiger sharks. 372 00:27:28,880 --> 00:27:32,800 A tiger shark is unmistakable in form. 373 00:27:32,800 --> 00:27:35,800 It has the dappling running down its sides, 374 00:27:35,800 --> 00:27:39,240 which gives it its tiger name. 375 00:27:40,720 --> 00:27:43,560 They'll feed on just about anything they can find in the water. 376 00:27:44,800 --> 00:27:49,640 And with those teeth, they can even go through the shell of a turtle. 377 00:27:51,240 --> 00:27:54,480 This is absolutely dazzling. 378 00:27:54,480 --> 00:27:57,240 I don't know which way to look! 379 00:27:57,240 --> 00:27:59,200 Tiger sharks, great hammerheads, 380 00:27:59,200 --> 00:28:01,920 lemons, bull sharks, reef sharks. 381 00:28:04,600 --> 00:28:06,680 It's the world's greatest safari, 382 00:28:06,680 --> 00:28:09,080 it just all happens underwater. 383 00:28:11,240 --> 00:28:13,320 Here and throughout the Bahamas, 384 00:28:13,320 --> 00:28:16,040 sharks are drawn in with food 385 00:28:16,040 --> 00:28:18,440 so tourists can reliably get close to them. 386 00:28:23,600 --> 00:28:27,240 Feeding of sharks is a hotly debated topic. 387 00:28:27,240 --> 00:28:31,320 there's people who think that it's a bad idea 388 00:28:31,320 --> 00:28:34,520 and might, potentially, change the behaviour of sharks, 389 00:28:34,520 --> 00:28:37,040 and I can totally see that, 390 00:28:37,040 --> 00:28:40,800 but there's no doubt that shark tourism here in the Bahamas 391 00:28:40,800 --> 00:28:43,240 is incredibly important. 392 00:28:44,920 --> 00:28:49,160 Each year, 20,000 people come to the Bahamas to dive with sharks... 393 00:28:50,600 --> 00:28:54,000 ..making it the largest shark diving industry in the world. 394 00:28:55,520 --> 00:28:58,280 Shark diving here in the Bahamas 395 00:28:58,280 --> 00:29:05,800 is worth an estimated $114 million every year to the local economy. 396 00:29:07,800 --> 00:29:11,920 Unquestionably, the sharks are worth more alive than they are dead. 397 00:29:13,720 --> 00:29:15,360 And that's hugely important 398 00:29:15,360 --> 00:29:17,800 for the survival of these extraordinary animals. 399 00:29:28,320 --> 00:29:30,360 INDISTINCT CHATTER 400 00:29:38,720 --> 00:29:40,280 All across the world, 401 00:29:40,280 --> 00:29:44,800 shark tourism is fast becoming a thriving industry - 402 00:29:44,800 --> 00:29:47,360 not just for dive operators, 403 00:29:47,360 --> 00:29:50,320 but boat drivers, hotels, restaurants, 404 00:29:50,320 --> 00:29:53,720 and bringing much-needed income to shark hot spots 405 00:29:53,720 --> 00:29:55,560 from all over the world. 406 00:29:58,280 --> 00:30:00,240 I came from Philadelphia today 407 00:30:00,240 --> 00:30:01,760 to swim with the sharks. 408 00:30:01,760 --> 00:30:03,760 It was just invigorating. 409 00:30:03,760 --> 00:30:05,520 It's a whole 'nother world down there. 410 00:30:10,600 --> 00:30:13,400 I'm from Argentina. 411 00:30:13,400 --> 00:30:16,280 It was a long trip but it's amazing. 412 00:30:18,760 --> 00:30:22,280 It's estimated that well over half a million people 413 00:30:22,280 --> 00:30:25,040 come to watch sharks every year. 414 00:30:25,040 --> 00:30:27,520 Not only are sharks gaining more advocates, 415 00:30:27,520 --> 00:30:31,120 but they now hold an indisputable monetary value. 416 00:30:35,000 --> 00:30:38,000 And this will certainly help to secure their future. 417 00:30:45,080 --> 00:30:48,160 Shark conservation is something that will require human effort 418 00:30:48,160 --> 00:30:50,000 for many years to come. 419 00:30:50,000 --> 00:30:51,960 And right here in the Bahamas, 420 00:30:51,960 --> 00:30:54,720 there's a very special project that's training up 421 00:30:54,720 --> 00:30:57,320 the next generation of shark champions. 422 00:31:02,480 --> 00:31:06,440 Marine biologist Jillian Morris has set up Sharks4Kids. 423 00:31:11,000 --> 00:31:13,400 A charity to show children across the Bahamas 424 00:31:13,400 --> 00:31:15,920 that sharks are something to celebrate, 425 00:31:15,920 --> 00:31:17,200 not to fear. 426 00:31:19,680 --> 00:31:24,240 I really believe that the best way to change the way people see sharks 427 00:31:24,240 --> 00:31:26,360 is to let them get in the water. 428 00:31:30,840 --> 00:31:32,520 We take kids out to see sharks 429 00:31:32,520 --> 00:31:34,560 and a lot of them are very afraid. 430 00:31:34,560 --> 00:31:36,320 They don't want to get off the boat, 431 00:31:36,320 --> 00:31:38,400 they don't want to step off the beach, 432 00:31:38,400 --> 00:31:40,440 and we get them to put a mask and a snorkel on, 433 00:31:40,440 --> 00:31:42,320 and we kind of ease them in. 434 00:31:42,320 --> 00:31:44,160 And then they're snorkelling around 435 00:31:44,160 --> 00:31:46,600 and they're seeing the sharks and the rays up close 436 00:31:46,600 --> 00:31:49,120 and realising they're not trying to attack them, 437 00:31:49,120 --> 00:31:51,560 that they're actually really beautiful animals. 438 00:32:03,600 --> 00:32:06,360 It's really incredible to see students go from being terrified 439 00:32:06,360 --> 00:32:07,960 and not wanting to get in the water, 440 00:32:07,960 --> 00:32:10,080 to we're having to drag them out - 441 00:32:10,080 --> 00:32:12,080 "We've got to go. It's time to go home." 442 00:32:12,080 --> 00:32:15,440 And to see that transition happen right in front of you, 443 00:32:15,440 --> 00:32:18,000 very quickly, is really, really powerful. 444 00:32:20,600 --> 00:32:22,640 The Bahamas is a shark sanctuary, 445 00:32:22,640 --> 00:32:25,960 which is incredible and has set a standard around the world 446 00:32:25,960 --> 00:32:29,080 for shark conservation, shark diving, shark science, 447 00:32:29,080 --> 00:32:33,640 and so it's vital to have the locals involved at all levels, 448 00:32:33,640 --> 00:32:35,040 from kids to adults, 449 00:32:35,040 --> 00:32:37,680 to protect the future of this sanctuary 450 00:32:37,680 --> 00:32:39,480 and the sharks here in the Bahamas. 451 00:32:50,280 --> 00:32:52,720 While places like the Bahamas offer protection 452 00:32:52,720 --> 00:32:54,160 when the sharks are here... 453 00:32:55,960 --> 00:32:58,960 ..once beyond the invisible boundary of the sanctuary, 454 00:32:58,960 --> 00:33:01,200 sharks are immediately vulnerable. 455 00:33:05,320 --> 00:33:08,680 Knowing where they go in this vast, featureless landscape 456 00:33:08,680 --> 00:33:11,680 is essential if we're to offer them protection. 457 00:33:15,200 --> 00:33:17,640 A few miles off the coast of Andros, 458 00:33:17,640 --> 00:33:19,880 the endless blue is interrupted... 459 00:33:22,760 --> 00:33:24,360 ..by a naval buoy. 460 00:33:30,960 --> 00:33:34,800 This lone beacon is a big draw for passing travellers... 461 00:33:38,040 --> 00:33:40,760 ..providing shelter for schools of fish... 462 00:33:42,880 --> 00:33:44,880 ..which attract the hunters. 463 00:33:46,640 --> 00:33:49,480 Top of the food chain out here are these - 464 00:33:49,480 --> 00:33:51,080 silky sharks. 465 00:33:53,840 --> 00:33:56,680 They get their name from the silky sheen of their skin. 466 00:34:01,640 --> 00:34:04,400 So little is known about the migrations 467 00:34:04,400 --> 00:34:06,440 of these open ocean drifters. 468 00:34:10,800 --> 00:34:12,880 When shark biologist Tristan Guttridge 469 00:34:12,880 --> 00:34:15,840 heard rumours of this location, 470 00:34:15,840 --> 00:34:19,800 it was an opportunity for him to try and uncover these secrets, 471 00:34:19,800 --> 00:34:23,080 which might just help protect these threatened sharks. 472 00:34:28,400 --> 00:34:30,800 There's nothing that gives me more energy 473 00:34:30,800 --> 00:34:33,160 than being in the water with sharks. 474 00:34:38,040 --> 00:34:41,720 These silky sharks, they're a completely different type of animal. 475 00:34:44,360 --> 00:34:46,680 There's just something about them that, you know, 476 00:34:46,680 --> 00:34:48,880 brings them closer and draws them in to you. 477 00:34:52,280 --> 00:34:55,560 They have this curious, bold personality 478 00:34:55,560 --> 00:34:57,800 and it is a bit intoxicating. 479 00:34:57,800 --> 00:34:59,040 And I love it. 480 00:35:00,680 --> 00:35:04,520 But this inquisitiveness is this shark's Achilles heel. 481 00:35:05,920 --> 00:35:08,560 Silkies are in trouble globally. 482 00:35:08,560 --> 00:35:12,640 And, in fact, silky sharks are the second-highest caught shark species 483 00:35:12,640 --> 00:35:13,840 in the world. 484 00:35:16,120 --> 00:35:19,360 Industrial fishing often uses floating objects, 485 00:35:19,360 --> 00:35:21,280 working just like the naval buoy, 486 00:35:21,280 --> 00:35:23,520 to attract an aggregate fish like tuna 487 00:35:23,520 --> 00:35:24,840 in the open ocean. 488 00:35:28,240 --> 00:35:30,160 But they don't just attract tuna. 489 00:35:32,560 --> 00:35:35,480 Every year, hundreds of thousands of silky sharks 490 00:35:35,480 --> 00:35:37,040 get accidentally caught. 491 00:35:38,680 --> 00:35:42,920 I see the evidence of the pressures that these animals are under 492 00:35:42,920 --> 00:35:44,480 from the hooks in the mouths 493 00:35:44,480 --> 00:35:46,800 and the leader wire that's coming out of it, 494 00:35:46,800 --> 00:35:49,840 you can see these sharks are...they're in trouble. 495 00:35:49,840 --> 00:35:52,800 They've got a lot to deal with out in the open ocean. 496 00:35:55,080 --> 00:35:56,920 Tristan wants to catch a shark 497 00:35:56,920 --> 00:35:59,200 in order to attach a tracker, 498 00:35:59,200 --> 00:36:01,440 which will reveal, for the first time, 499 00:36:01,440 --> 00:36:03,040 where these curious sharks go. 500 00:36:07,120 --> 00:36:10,560 One method that we can use to catch silkies is 501 00:36:10,560 --> 00:36:13,840 that you can actually bend the top of the tail over 502 00:36:13,840 --> 00:36:18,280 and it sends them into this kind of bizarre trance-like state. 503 00:36:18,280 --> 00:36:21,320 And if you turn them upside down at the same time, 504 00:36:21,320 --> 00:36:24,560 then they're almost playing dead, they're just out. 505 00:36:24,560 --> 00:36:26,600 It's not fully understood why, 506 00:36:26,600 --> 00:36:30,080 but many shark species enter this trance-like state 507 00:36:30,080 --> 00:36:33,360 called tonic immobility when upside down, 508 00:36:33,360 --> 00:36:36,600 enabling the team to tether the shark next to the boat. 509 00:36:36,600 --> 00:36:38,360 INDISTINCT SPEECH 510 00:36:42,720 --> 00:36:45,280 A satellite tag is fixed to its dorsal fin. 511 00:36:47,560 --> 00:36:51,200 Every five minutes, this tag will record important information, 512 00:36:51,200 --> 00:36:55,120 including depth, light level and water temperature. 513 00:36:58,920 --> 00:37:01,760 After 30 days, it'll pop to the surface 514 00:37:01,760 --> 00:37:04,640 and start sending a stream of data to Tristan. 515 00:37:07,240 --> 00:37:09,800 TRISTAN: There's nothing more exciting than the few days 516 00:37:09,800 --> 00:37:11,520 when we know a tag is going to pop 517 00:37:11,520 --> 00:37:13,040 as to where it's going to pop. 518 00:37:14,560 --> 00:37:18,760 It's very important that we learn more about their migration patterns, 519 00:37:18,760 --> 00:37:20,280 their population structure, 520 00:37:20,280 --> 00:37:23,440 in order to try and put management measures in place 521 00:37:23,440 --> 00:37:25,120 to improve their conservation. 522 00:37:27,920 --> 00:37:31,000 They deserve to be on this planet. 523 00:37:31,000 --> 00:37:34,240 Like us and like anything, they deserve to be here 524 00:37:34,240 --> 00:37:38,280 and we, as humans, should be responsible. 525 00:37:38,280 --> 00:37:41,920 So it is critical that we learn more about these animals 526 00:37:41,920 --> 00:37:43,760 and it's critical that we protect them. 527 00:37:47,480 --> 00:37:51,280 Tristan's tags have shown that these sharks not only traverse oceans... 528 00:37:53,560 --> 00:37:56,800 ..but dive down to feed at depths of over 400 metres. 529 00:37:59,240 --> 00:38:01,600 Showing that if we want to protect sharks, 530 00:38:01,600 --> 00:38:04,480 we need to look after every part of our oceans. 531 00:38:13,560 --> 00:38:15,640 Satellite tags are now being deployed 532 00:38:15,640 --> 00:38:18,320 on many different species of sharks 533 00:38:18,320 --> 00:38:20,880 and they're revealing some incredible journeys. 534 00:38:24,920 --> 00:38:27,160 The greatest distance ever recorded 535 00:38:27,160 --> 00:38:30,520 was by a great white shark named Nicole, 536 00:38:30,520 --> 00:38:33,920 who swam from South Africa to Australia 537 00:38:33,920 --> 00:38:35,600 and back again - 538 00:38:35,600 --> 00:38:39,520 a staggering 12,000 miles in just nine months. 539 00:38:49,200 --> 00:38:53,480 While understanding where these top predators go is important, 540 00:38:53,480 --> 00:38:56,280 another vital piece of this conservation puzzle 541 00:38:56,280 --> 00:38:58,520 is understanding why they go. 542 00:39:08,240 --> 00:39:11,360 Just off the coast of Bimini in the Bahamas, 543 00:39:11,360 --> 00:39:14,360 there's a dive site that, for a few months each year, 544 00:39:14,360 --> 00:39:16,600 provides a close encounter 545 00:39:16,600 --> 00:39:20,640 with one of our most iconic and well-known migratory sharks. 546 00:39:24,640 --> 00:39:27,400 This is the only place in the whole world 547 00:39:27,400 --> 00:39:31,480 where you can reliably see great hammerhead sharks. 548 00:39:33,840 --> 00:39:35,720 So we have dozens of sharks around us. 549 00:39:35,720 --> 00:39:38,760 Most are like this one here. 550 00:39:38,760 --> 00:39:40,040 It's a nurse shark. 551 00:39:42,400 --> 00:39:45,200 And the reason they have this name is that when they're feeding, 552 00:39:45,200 --> 00:39:47,400 they make a sucking noise, 553 00:39:47,400 --> 00:39:50,560 kind of like a baby when it's nursing, 554 00:39:50,560 --> 00:39:53,000 when it's feeding. 555 00:39:53,000 --> 00:39:55,640 You can see that they're quite content lying on the bottom. 556 00:39:55,640 --> 00:40:00,080 They can pump water through their gills 557 00:40:00,080 --> 00:40:03,320 and they don't have to swim constantly in order to breathe, 558 00:40:03,320 --> 00:40:05,000 like many other sharks do. 559 00:40:07,200 --> 00:40:10,720 But this creature that's heading towards us now, 560 00:40:10,720 --> 00:40:13,160 that really is the main event. 561 00:40:14,360 --> 00:40:15,840 It's a great hammerhead. 562 00:40:17,560 --> 00:40:22,560 There are at least three of them around us right now. 563 00:40:22,560 --> 00:40:26,720 And while the nurse sharks are quite dopey 564 00:40:26,720 --> 00:40:29,080 and just hanging out on the bottom, 565 00:40:29,080 --> 00:40:31,840 this is a far more targeted predator. 566 00:40:33,000 --> 00:40:36,640 There is nothing else quite like a great hammerhead shark. 567 00:40:36,640 --> 00:40:38,920 The shape of the head, 568 00:40:38,920 --> 00:40:41,080 the giant dorsal fin. 569 00:40:41,080 --> 00:40:43,520 It's so unusual-looking 570 00:40:43,520 --> 00:40:46,960 and, yet, so perfectly adapted to its job. 571 00:40:48,640 --> 00:40:50,920 Shaking the hammerhead from side to side 572 00:40:50,920 --> 00:40:52,560 as it moves along the bottom, 573 00:40:52,560 --> 00:40:55,720 sensing the potential moving muscles of its prey. 574 00:41:02,880 --> 00:41:05,720 Perhaps the most incredible thing about this 575 00:41:05,720 --> 00:41:09,320 is that great hammerheads are an endangered species. 576 00:41:10,800 --> 00:41:13,800 There are very, very few of these almighty sharks left 577 00:41:13,800 --> 00:41:15,320 in the whole world. 578 00:41:17,080 --> 00:41:20,080 And right now, I think we have seven. 579 00:41:22,320 --> 00:41:24,640 I don't quite know what to say. 580 00:41:24,640 --> 00:41:26,400 I'm completely blown away. 581 00:41:33,520 --> 00:41:36,560 These great hammerheads are seasonal visitors, 582 00:41:36,560 --> 00:41:38,240 spending the winter months here, 583 00:41:38,240 --> 00:41:39,840 between December and April. 584 00:41:43,560 --> 00:41:46,000 Many return year after year. 585 00:41:49,960 --> 00:41:53,000 The scientists have at least 30 individuals 586 00:41:53,000 --> 00:41:55,240 that they know by name... 587 00:41:56,480 --> 00:41:59,600 ..and not just by name, but by personality 588 00:41:59,600 --> 00:42:01,320 and character and behaviour. 589 00:42:02,920 --> 00:42:05,960 And even in the short time since I've been here, 590 00:42:05,960 --> 00:42:09,880 I've been starting to get to know the individual personalities here. 591 00:42:11,440 --> 00:42:14,120 You might not think of a shark as having a personality, 592 00:42:14,120 --> 00:42:15,800 but they very much do. 593 00:42:15,800 --> 00:42:19,640 Some of them are quite bold and dramatic, 594 00:42:19,640 --> 00:42:22,640 and others are real gentle giants. 595 00:42:25,720 --> 00:42:30,000 This almighty great hammerhead here is called Gaia. 596 00:42:30,000 --> 00:42:32,440 She's a female. 597 00:42:32,440 --> 00:42:34,240 And the largest that they see here. 598 00:42:37,080 --> 00:42:39,120 What an absolute beauty! 599 00:42:44,440 --> 00:42:46,880 I will never, ever get tired of this. 600 00:42:49,480 --> 00:42:51,520 Holy Moley! 601 00:42:51,520 --> 00:42:53,720 HE LAUGHS EXCITEDLY 602 00:42:56,560 --> 00:42:58,520 For five months of the year, 603 00:42:58,520 --> 00:43:00,880 these hammerheads are seen virtually every day. 604 00:43:02,800 --> 00:43:05,520 But in April, they suddenly disappear. 605 00:43:16,880 --> 00:43:20,200 One female was tagged here at Bimini. 606 00:43:20,200 --> 00:43:23,000 She then headed north to the coast of the Carolinas, 607 00:43:23,000 --> 00:43:25,000 before turning south again, 608 00:43:25,000 --> 00:43:28,200 ending up off the coast of Florida. 609 00:43:28,200 --> 00:43:32,320 A journey of over 3,000 miles in less than two months. 610 00:43:40,080 --> 00:43:43,440 But what's causing these ocean wanderers to travel so far 611 00:43:43,440 --> 00:43:45,080 and so fast? 612 00:43:52,040 --> 00:43:54,280 I'm taking to the air to find out. 613 00:44:02,680 --> 00:44:05,280 This is Palm Beach, Florida. 614 00:44:05,280 --> 00:44:07,720 It's a playground for the rich and the famous. 615 00:44:07,720 --> 00:44:10,720 But little do they know that just off the coast 616 00:44:10,720 --> 00:44:13,960 is one of the greatest gatherings of large predators on the planet. 617 00:44:23,320 --> 00:44:25,280 These are blacktip sharks. 618 00:44:31,720 --> 00:44:33,640 Massing in their thousands 619 00:44:33,640 --> 00:44:37,120 before migrating north to their summer feeding grounds 620 00:44:37,120 --> 00:44:38,960 off the coast of North Carolina. 621 00:44:41,040 --> 00:44:45,440 It's these sharks that attract a host of larger predatory sharks, 622 00:44:45,440 --> 00:44:47,520 including the great hammerheads, 623 00:44:47,520 --> 00:44:51,360 which travel from the Bahamas to feast on this bounty of food. 624 00:44:54,800 --> 00:44:56,840 I've joined Stephen Kajiura, 625 00:44:56,840 --> 00:44:59,440 a professor at Florida Atlantic University. 626 00:45:01,520 --> 00:45:05,360 Each year, he takes to the air to monitor the number of sharks. 627 00:45:08,440 --> 00:45:14,320 Just a slick of sharks going on all the way parallel to the coast. 628 00:45:14,320 --> 00:45:16,160 That is absolutely fantastic. 629 00:45:17,400 --> 00:45:20,640 They stand out so well against the sandy bottom, don't they? 630 00:45:20,640 --> 00:45:22,640 That's one of the reasons we're so successful 631 00:45:22,640 --> 00:45:24,320 with the aerial surveys here. 632 00:45:24,320 --> 00:45:26,360 We have clear water, a light, sandy bottom, 633 00:45:26,360 --> 00:45:27,760 we're able to see everything. 634 00:45:27,760 --> 00:45:30,200 And they're in nice and shallow. They're nice and shallow. 635 00:45:30,200 --> 00:45:32,280 They really make it easy for you, don't they? 636 00:45:33,400 --> 00:45:35,560 But all's not what it seems. 637 00:45:35,560 --> 00:45:37,720 Stephen's long-term study has shown 638 00:45:37,720 --> 00:45:40,640 that this spectacular migration is changing. 639 00:45:42,360 --> 00:45:45,520 And this could have serious consequences. 640 00:45:45,520 --> 00:45:48,680 I've been doing these aerial surveys for the last nine years. 641 00:45:48,680 --> 00:45:51,320 We've seen this decline in the number of sharks 642 00:45:51,320 --> 00:45:52,720 over the past nine years. 643 00:45:52,720 --> 00:45:54,160 At the same time, 644 00:45:54,160 --> 00:45:56,800 we've seen an increase in the water temperature down here. 645 00:45:56,800 --> 00:45:58,840 They have a very narrow thermal tolerance. 646 00:45:58,840 --> 00:46:02,080 They like water between about 21 and 25 Celsius. 647 00:46:02,080 --> 00:46:04,320 And as water temperatures keep rising, 648 00:46:04,320 --> 00:46:06,760 we're getting fewer and fewer sharks coming this far south. 649 00:46:06,760 --> 00:46:09,480 Presumably the blacktips that you've got here, 650 00:46:09,480 --> 00:46:11,600 there are constant interactions between them 651 00:46:11,600 --> 00:46:13,360 and the larger predatory sharks 652 00:46:13,360 --> 00:46:15,840 like the tigers, the great hammerheads and the bulls. 653 00:46:15,840 --> 00:46:17,960 How is that likely to be affected? 654 00:46:17,960 --> 00:46:19,520 That's a really good question. 655 00:46:19,520 --> 00:46:22,280 If you don't have these blacktips sweeping down here 656 00:46:22,280 --> 00:46:24,640 in the tens of thousands every spring, 657 00:46:24,640 --> 00:46:26,840 there's no food for the big hammerheads 658 00:46:26,840 --> 00:46:29,280 and these blacktips are not eating all the bait fish. 659 00:46:29,280 --> 00:46:31,640 And so, we don't even know what might happen. 660 00:46:37,080 --> 00:46:38,480 You know, these ecosystems 661 00:46:38,480 --> 00:46:40,840 have remained pretty much unchanged for millennia, 662 00:46:40,840 --> 00:46:44,120 but they are dramatically changing in my lifetime, 663 00:46:44,120 --> 00:46:46,920 and where that will lead we simply don't know. 664 00:46:54,080 --> 00:46:57,560 The rate at which our seas are heating up is accelerating. 665 00:46:59,360 --> 00:47:02,440 And the effects of this warming are now being felt 666 00:47:02,440 --> 00:47:04,400 in every one of our oceans. 667 00:47:18,040 --> 00:47:21,440 Sharks are under pressure from all sides - 668 00:47:21,440 --> 00:47:24,120 fishing, their habitats changing, 669 00:47:24,120 --> 00:47:27,160 and now, in these protected waters, 670 00:47:27,160 --> 00:47:28,960 their fellow sea creatures. 671 00:47:35,600 --> 00:47:39,560 Recently, an unwanted visitor has appeared in Caribbean waters. 672 00:47:46,720 --> 00:47:49,480 This is a lionfish. 673 00:47:52,960 --> 00:47:56,960 A predator that could eat fish populations out of existence... 674 00:47:58,640 --> 00:48:01,480 ..threatening the future of the resident sharks. 675 00:48:08,000 --> 00:48:10,360 Ten years ago, I saw for myself 676 00:48:10,360 --> 00:48:14,440 just what devastating predators they are in their native waters 677 00:48:14,440 --> 00:48:15,760 off Malaysia. 678 00:48:17,720 --> 00:48:19,840 There's a small fish over here. 679 00:48:19,840 --> 00:48:21,600 The lionfish has spotted it. 680 00:48:23,000 --> 00:48:24,800 This could be trouble. 681 00:48:26,120 --> 00:48:28,360 It's moving in. 682 00:48:28,360 --> 00:48:32,000 Oh! Unbelievable! 683 00:48:32,000 --> 00:48:34,440 Did you see the speed of that strike? 684 00:48:37,320 --> 00:48:41,840 Lionfish eat about 70 different species of fish and invertebrate. 685 00:48:44,840 --> 00:48:46,680 If it fits in their mouth, 686 00:48:46,680 --> 00:48:48,400 they'll eat it. 687 00:48:53,240 --> 00:48:54,680 It did it again. 688 00:48:56,200 --> 00:49:00,400 This is just the most astounding display of feeding 689 00:49:00,400 --> 00:49:02,560 I think I've ever seen. 690 00:49:10,200 --> 00:49:13,200 Such an elegant fish is, unsurprisingly, 691 00:49:13,200 --> 00:49:15,200 a favourite of the aquarium trade. 692 00:49:16,680 --> 00:49:21,280 And in the 1980s, a few unwanted pets ended up being released 693 00:49:21,280 --> 00:49:22,720 in the seas off Florida... 694 00:49:25,360 --> 00:49:27,320 ..with devastating results. 695 00:49:31,640 --> 00:49:35,320 In just over 30 years, they've spread from coastal Florida 696 00:49:35,320 --> 00:49:36,720 with alarming speed. 697 00:49:39,000 --> 00:49:42,040 They're now found as far north as New York 698 00:49:42,040 --> 00:49:44,640 and south to Brazil. 699 00:49:45,920 --> 00:49:48,920 This is the wrong fish in the wrong place 700 00:49:48,920 --> 00:49:50,360 and at the wrong time. 701 00:49:53,800 --> 00:49:57,680 And it's threatening to unbalance the already fragile system 702 00:49:57,680 --> 00:49:59,880 upon which the sharks depend. 703 00:50:03,600 --> 00:50:05,800 This is a growing problem 704 00:50:05,800 --> 00:50:08,640 that people like marine biologist Alex Fogg 705 00:50:08,640 --> 00:50:10,480 are trying to find a solution to. 706 00:50:11,520 --> 00:50:13,640 ALEX: The reefs have changed actually quite a bit 707 00:50:13,640 --> 00:50:14,920 since I first started diving. 708 00:50:14,920 --> 00:50:18,200 I started diving about ten years ago and in this area in particular, 709 00:50:18,200 --> 00:50:19,920 lionfish weren't here yet. 710 00:50:27,000 --> 00:50:29,600 When we first started seeing lionfish on the reef 711 00:50:29,600 --> 00:50:32,760 it was one here or one there, but now you go to a reef site 712 00:50:32,760 --> 00:50:35,360 and you can see upwards of 100 lionfish. 713 00:50:35,360 --> 00:50:37,360 I mean, they're here eating everything. 714 00:50:37,360 --> 00:50:39,920 It's like an all-you-can-eat buffet, if you will. 715 00:50:41,960 --> 00:50:44,000 They're not just voracious hunters, 716 00:50:44,000 --> 00:50:46,040 they're prolific breeders too. 717 00:50:47,680 --> 00:50:53,960 A female lionfish can lay more than 20,000 eggs every four days. 718 00:50:55,800 --> 00:51:00,200 They can reach densities of over 200 adults per acre of reef 719 00:51:00,200 --> 00:51:05,320 and that quantity can hoover up nearly half a million fish a year. 720 00:51:08,600 --> 00:51:13,040 This is having a devastating effect on an already fragile ecosystem. 721 00:51:14,360 --> 00:51:16,680 But Alex has a plan. 722 00:51:20,800 --> 00:51:22,680 You can't really catch them on hook and lines. 723 00:51:22,680 --> 00:51:24,840 There's really only one way to harvest lion fish 724 00:51:24,840 --> 00:51:27,560 and that's through diving and harvesting with spears. 725 00:51:33,400 --> 00:51:35,680 And all these fish don't go to waste. 726 00:51:38,240 --> 00:51:41,480 Lionfish are definitely one of the most environmentally-friendly fish 727 00:51:41,480 --> 00:51:42,800 that you can actually eat. 728 00:51:44,600 --> 00:51:47,160 This is one fish that we want to eat into extinction. 729 00:51:48,560 --> 00:51:51,240 Hey, Chef. Got you a bunch of fish. Right, man. Appreciate it. 730 00:51:51,240 --> 00:51:52,800 Thank you very much. Thank you. 731 00:51:58,960 --> 00:52:01,560 Alex hopes that by making a commercial market 732 00:52:01,560 --> 00:52:03,800 for these lionfish, more will be caught... 733 00:52:05,160 --> 00:52:07,680 ..allowing reefs and sharks to recover. 734 00:52:10,920 --> 00:52:12,960 Ten years down the road from now, 735 00:52:12,960 --> 00:52:15,000 lionfish are still going to be here. 736 00:52:15,000 --> 00:52:17,480 Are they going to be at the numbers that we have today? 737 00:52:17,480 --> 00:52:20,840 I'm not sure. I think that if we can just get lionfish to a point 738 00:52:20,840 --> 00:52:23,160 to where the ecosystem can actually deal with it, 739 00:52:23,160 --> 00:52:25,120 or they find their space in the ecosystem, 740 00:52:25,120 --> 00:52:26,160 that's our best bet. 741 00:52:28,800 --> 00:52:32,040 The market for lionfish in restaurants is growing. 742 00:52:33,160 --> 00:52:35,480 But to fully combat this invasion, 743 00:52:35,480 --> 00:52:37,720 things are being taken a step further. 744 00:52:45,880 --> 00:52:50,800 Along the coast of America, locals have created lionfish derbies. 745 00:52:53,400 --> 00:52:57,480 The aim - to collect and remove as many lionfish as possible. 746 00:53:07,200 --> 00:53:11,000 Each fish is measured and prizes are awarded for catching the most, 747 00:53:11,000 --> 00:53:13,200 the biggest, 748 00:53:13,200 --> 00:53:15,320 and the smallest lionfish. 749 00:53:27,120 --> 00:53:29,320 Hundreds gather to share in the prize... 750 00:53:30,920 --> 00:53:32,360 ..and eat the catch. 751 00:53:42,560 --> 00:53:45,600 These derbies serve to reduce numbers, 752 00:53:45,600 --> 00:53:48,120 as well as raising awareness of a fish 753 00:53:48,120 --> 00:53:52,400 that threatens the ocean ecosystems upon which the sharks rely. 754 00:53:57,520 --> 00:54:00,040 INDISTINCT CHATTER 755 00:54:08,080 --> 00:54:11,080 Our blue planet is defined by its oceans... 756 00:54:15,840 --> 00:54:18,920 ..and if they are to stay healthy and productive, 757 00:54:18,920 --> 00:54:22,520 we need a healthy population of sharks. 758 00:54:25,560 --> 00:54:30,280 At present, sharks are being killed faster than they can reproduce 759 00:54:30,280 --> 00:54:34,120 and we're set to lose some of our most iconic species 760 00:54:34,120 --> 00:54:35,760 in the next 50 years. 761 00:54:42,080 --> 00:54:43,760 But across the globe, 762 00:54:43,760 --> 00:54:48,360 many people are working tirelessly to uncover the secrets of sharks 763 00:54:48,360 --> 00:54:50,000 in order to save them. 764 00:54:53,600 --> 00:54:56,880 People are seeing sharks in their true light 765 00:54:56,880 --> 00:54:59,200 and starting to appreciate them 766 00:54:59,200 --> 00:55:02,000 for the essential role they play in our oceans. 767 00:55:06,000 --> 00:55:08,520 There is still much work that needs to be done... 768 00:55:10,760 --> 00:55:12,760 ..but, for now, there is hope... 769 00:55:14,600 --> 00:55:18,680 ..for our oceans are packed with the ingredients for recovery. 770 00:55:23,520 --> 00:55:28,400 The seas are full of tiny, microscopic life 771 00:55:28,400 --> 00:55:33,040 just looking for somewhere to fix and make home. 772 00:55:37,720 --> 00:55:40,120 This is the Sapona. 773 00:55:44,800 --> 00:55:49,320 It was grounded here in a hurricane many decades ago, 774 00:55:49,320 --> 00:55:53,160 and ever since, it's become a living reef... 775 00:55:54,600 --> 00:55:56,920 ..absolutely bursting with life. 776 00:56:01,200 --> 00:56:02,480 So many fish. 777 00:56:05,320 --> 00:56:06,760 So beautiful. 778 00:56:12,080 --> 00:56:15,920 The superstructure makes a perfect habitat, 779 00:56:15,920 --> 00:56:19,760 places for them to hide from predators. 780 00:56:19,760 --> 00:56:24,960 And it's covered with encrusting soft corals and fans. 781 00:56:30,560 --> 00:56:33,480 All sorts of animals take up shelter inside. 782 00:56:37,960 --> 00:56:40,240 Oh, stingray! 783 00:56:44,480 --> 00:56:50,880 It's like swimming through the ribcage of an almighty whale 784 00:56:50,880 --> 00:56:52,880 lying on the bottom. 785 00:56:52,880 --> 00:56:54,480 Incredible. 786 00:56:59,800 --> 00:57:04,360 This is the basis of the food chain upon which sharks depend. 787 00:57:15,680 --> 00:57:20,120 If we protect our seas then life will bounce back in our oceans, 788 00:57:20,120 --> 00:57:21,920 if we give it the chance. 789 00:57:27,480 --> 00:57:30,960 The interconnectedness of our oceans and their inhabitants 790 00:57:30,960 --> 00:57:33,200 is intricate and far-reaching. 791 00:57:35,840 --> 00:57:38,760 Sharks depend on the creatures around them 792 00:57:38,760 --> 00:57:40,280 as these creatures in turn 793 00:57:40,280 --> 00:57:41,840 depend on the sharks. 794 00:57:44,480 --> 00:57:49,760 They've been stalking our seas for at least 400 million years. 795 00:57:49,760 --> 00:57:52,800 I hope they've got a few million more left in them yet. 796 00:57:55,680 --> 00:57:59,520 The Bahamas are at the forefront of shark research and conservation. 797 00:58:00,760 --> 00:58:03,600 And lessons learnt here now need to be applied 798 00:58:03,600 --> 00:58:05,400 all across our blue planet. 799 00:58:10,760 --> 00:58:13,720 The future of sharks is in our hands. 800 00:58:16,360 --> 00:58:20,480 And it's for us to decide where this sharks' tale goes next.