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These are the user uploaded subtitles that are being translated: 1 00:00:42,160 --> 00:00:44,600 In the course of making Blue Planet II, 2 00:00:44,680 --> 00:00:48,400 we've explored every corner of the underwater world. 3 00:00:50,640 --> 00:00:53,600 We've encountered extraordinary animals, 4 00:01:00,000 --> 00:01:05,160 and discovered new insights into how life is lived beneath the waves. 5 00:01:11,280 --> 00:01:15,400 For years we thought that the oceans were so vast 6 00:01:15,480 --> 00:01:18,800 and the inhabitants so infinitely numerous 7 00:01:18,880 --> 00:01:22,400 that nothing we could do could have an effect upon them. 8 00:01:22,480 --> 00:01:24,560 But now we know that was wrong. 9 00:01:25,400 --> 00:01:30,800 The oceans are under threat now as never before in human history. 10 00:01:32,360 --> 00:01:34,320 In this final episode, 11 00:01:34,400 --> 00:01:39,520 we will meet the pioneers who are striving to turn things around. 12 00:01:44,280 --> 00:01:49,160 People who are helping to save the ocean's most vulnerable inhabitants 13 00:01:51,520 --> 00:01:55,760 and dedicating their lives to protecting the seas. 14 00:01:58,640 --> 00:02:00,840 But is time running out? 15 00:02:02,920 --> 00:02:07,400 Many people believe that our oceans have reached a crisis point. 16 00:02:07,920 --> 00:02:11,720 So just how fragile is our blue planet? 17 00:02:27,360 --> 00:02:30,320 Winter in the Arctic Circle. 18 00:02:32,600 --> 00:02:36,000 Every year, the waters of Norway are the setting 19 00:02:36,080 --> 00:02:39,560 for one of the greatest wildlife spectacles in the ocean. 20 00:02:40,960 --> 00:02:45,320 Over a billion herring pour into these fields. 21 00:02:47,400 --> 00:02:50,320 The Blue Planet II team spent three years 22 00:02:50,400 --> 00:02:52,920 documenting this astonishing event. 23 00:02:57,360 --> 00:03:00,760 Such a wealth of prey attracts predators 24 00:03:00,840 --> 00:03:02,880 in extraordinary numbers. 25 00:03:06,160 --> 00:03:07,600 Orcas 26 00:03:12,600 --> 00:03:14,520 and humpback whales. 27 00:03:35,120 --> 00:03:39,520 But this migration hasn't always been so bountiful. 28 00:03:40,440 --> 00:03:44,400 Leif Notastad is a Norwegian fisheries scientist. 29 00:03:45,240 --> 00:03:48,000 It's been one of the most important fisheries 30 00:03:48,120 --> 00:03:51,800 that we had for centuries along the whole coast of Norway. 31 00:03:51,880 --> 00:03:53,880 But in the late 1960s 32 00:03:53,960 --> 00:03:57,760 the herrings that we see around us here was on the brink of collapse. 33 00:04:02,560 --> 00:04:05,560 50 years ago, fishing was so intensive 34 00:04:05,640 --> 00:04:08,320 that the herring had all but disappeared. 35 00:04:10,680 --> 00:04:12,920 Orcas were seen as rivals 36 00:04:13,000 --> 00:04:15,120 and hundreds of them were killed. 37 00:04:22,040 --> 00:04:26,400 It was only after the Norwegian government imposed severe restrictions 38 00:04:26,480 --> 00:04:28,680 that the herring began to recover. 39 00:04:35,200 --> 00:04:39,960 Today, this is once again an immensely productive fishery, 40 00:04:40,840 --> 00:04:44,240 closely monitored by teams of scientists. 41 00:04:47,960 --> 00:04:50,280 Marine biologist Eve Jourdain 42 00:04:50,360 --> 00:04:53,360 is one of the resident orca experts. 43 00:04:53,920 --> 00:04:56,920 From 1982, orcas got protected in Norway 44 00:04:57,000 --> 00:05:01,640 and we have clearly one of the largest orca population in the world out here. 45 00:05:04,040 --> 00:05:06,880 There are now over a thousand orcas here. 46 00:05:07,080 --> 00:05:10,560 But with so many mouths to feed, including ours, 47 00:05:10,640 --> 00:05:13,240 can the mistakes of the past be avoided? 48 00:05:15,520 --> 00:05:17,720 To answer this vital question, 49 00:05:17,800 --> 00:05:21,840 Eve and her team are using multi sensor camera tags. 50 00:05:24,080 --> 00:05:29,720 With the tags we try to see how the orcas interact with their prey. 51 00:05:29,800 --> 00:05:33,320 How they hunt and all about the underwater behaviour 52 00:05:33,400 --> 00:05:35,680 that we are not able to see from the boat. 53 00:05:37,960 --> 00:05:40,160 A tag has to be attached 54 00:05:40,240 --> 00:05:42,480 to the orca in exactly the right position. 55 00:05:45,520 --> 00:05:47,720 Here it goes. Here it comes. 56 00:05:52,160 --> 00:05:53,840 Oh, that's a good shot. 57 00:05:58,160 --> 00:06:01,120 It is the least invasive method. It is suction cups. 58 00:06:01,280 --> 00:06:03,720 So it is not a scratch on the whale afterwards 59 00:06:03,800 --> 00:06:05,520 which is something we really like. 60 00:06:08,880 --> 00:06:10,720 While studying the orcas, 61 00:06:10,800 --> 00:06:14,320 Eve noticed a worrying change in their behaviour. 62 00:06:15,240 --> 00:06:18,440 They had worked out the easiest way to get a meal. 63 00:06:19,840 --> 00:06:22,080 We have seen that the orcas are waiting 64 00:06:22,160 --> 00:06:24,640 for those fishing boats to drop the net. 65 00:06:26,080 --> 00:06:27,960 It acts like a dinner bell 66 00:06:28,040 --> 00:06:30,880 and then all the orcas of the area gather. 67 00:06:31,840 --> 00:06:33,600 Quite a lot of herring slip from the net 68 00:06:33,680 --> 00:06:36,320 and this is exactly what the orcas are looking for. 69 00:06:39,760 --> 00:06:44,000 But this new tactic is dangerous, as Eve has witnessed. 70 00:06:45,280 --> 00:06:48,280 We were there to monitor the behaviour of the orcas 71 00:06:48,360 --> 00:06:50,520 scavenging around the nets. 72 00:06:50,600 --> 00:06:53,600 And we realised that one large adult male 73 00:06:53,680 --> 00:06:55,720 was actually trapped inside the net. 74 00:06:56,800 --> 00:06:59,080 When the fishermen started to retrieve the net 75 00:06:59,160 --> 00:07:01,760 the orca was obviously starting to panic 76 00:07:01,840 --> 00:07:05,000 and trying to pull as much as he could. 77 00:07:05,080 --> 00:07:07,520 This orca was really fighting for his life. 78 00:07:09,680 --> 00:07:12,000 Stringent rules require fishermen 79 00:07:12,080 --> 00:07:14,840 to get permission before they open their nets. 80 00:07:16,680 --> 00:07:18,200 But that took time. 81 00:07:23,080 --> 00:07:25,000 It was such a long process. 82 00:07:25,720 --> 00:07:29,840 We thought that the whale was going to die of exhaustion. 83 00:07:33,640 --> 00:07:36,400 Thankfully, the fishermen finally got the clearance 84 00:07:36,480 --> 00:07:39,960 to release their net freeing the exhausted orca. 85 00:07:51,280 --> 00:07:55,960 It was a huge relief to see that this orca made it until the end 86 00:07:56,040 --> 00:07:58,600 and finally got back to his family. 87 00:08:01,800 --> 00:08:05,600 With marine mammals and humans competing so directly 88 00:08:05,680 --> 00:08:07,920 accidents are inevitable. 89 00:08:12,320 --> 00:08:14,800 Two days after tagging an orca, 90 00:08:14,880 --> 00:08:17,720 it's released and Eve collects it. 91 00:08:21,200 --> 00:08:23,280 This tag is full of secrets, you know, 92 00:08:23,360 --> 00:08:25,560 because it has been on the whale for several days 93 00:08:25,640 --> 00:08:28,800 and will just reveal exactly what the whales have been doing. 94 00:08:29,440 --> 00:08:33,760 Pictures from the tag reveal the hunting technique in detail. 95 00:08:40,240 --> 00:08:43,160 They dive below the ball of fish 96 00:08:46,000 --> 00:08:47,800 and then back flip. 97 00:08:51,120 --> 00:08:55,040 The tail slap stuns the herring. 98 00:08:57,520 --> 00:09:01,600 Eve can even work out how many fish the orcas are taking. 99 00:09:02,400 --> 00:09:06,360 They can kill up to 30 herring with just one tail slap. 100 00:09:06,440 --> 00:09:08,320 And then what is pretty amazing is 101 00:09:08,400 --> 00:09:11,440 all the individuals of the group share the dead herring. 102 00:09:13,000 --> 00:09:15,760 And it's not just the orcas feeding here... 103 00:09:17,920 --> 00:09:21,440 Humpback whales are also drawn to the feast. 104 00:09:34,880 --> 00:09:37,320 They too are being tagged and monitored 105 00:09:37,400 --> 00:09:39,360 giving fishery scientist Leif 106 00:09:39,440 --> 00:09:42,880 a complete picture of how much herring is being eaten. 107 00:09:43,840 --> 00:09:47,680 The whales, they take probably less than 1%. 108 00:09:48,680 --> 00:09:51,920 The fishermen take less than 10%. 109 00:09:52,640 --> 00:09:56,440 So the balance there is that there is enough for everybody. 110 00:09:56,520 --> 00:09:59,400 Given that we manage to stock in sustainable 111 00:09:59,480 --> 00:10:01,320 and a long term sustainable way. 112 00:10:10,480 --> 00:10:14,960 But it's estimated that almost a third of ocean fisheries 113 00:10:15,040 --> 00:10:17,160 are being over exploited. 114 00:10:21,480 --> 00:10:24,240 The remarkable recovery of the herring here 115 00:10:24,320 --> 00:10:28,160 demonstrates what can happen if a fishery is carefully managed. 116 00:10:46,080 --> 00:10:49,200 Our maltreatment of the seas has many effects. 117 00:10:51,000 --> 00:10:52,640 Some are predictable, 118 00:10:53,680 --> 00:10:57,360 but there are others that are rather more surprising. 119 00:11:06,040 --> 00:11:07,720 Southeast Asia. 120 00:11:09,960 --> 00:11:13,960 The coral reefs here are among the richest on the planet. 121 00:11:24,000 --> 00:11:26,680 Marine biologist Steve Simpson, 122 00:11:26,760 --> 00:11:29,680 is discovering how important sound is 123 00:11:29,760 --> 00:11:33,200 to the animals that live in these bustling coral cities. 124 00:11:34,920 --> 00:11:37,400 We're only now just realising by listening underwater 125 00:11:37,480 --> 00:11:39,440 that the fish are making all these sounds. 126 00:11:39,720 --> 00:11:42,360 They use sound to attract a mate. 127 00:11:42,440 --> 00:11:44,600 To try and scare away a predator. 128 00:11:45,720 --> 00:11:49,560 You hear pops and grunts and gurgles and snaps. 129 00:11:52,160 --> 00:11:53,960 There's a whole language underwater 130 00:11:54,040 --> 00:11:56,440 that we're only just starting to get a handle on. 131 00:12:15,880 --> 00:12:19,880 Using an advanced multi directional hydrophone, 132 00:12:19,960 --> 00:12:23,800 Steve is trying to make sense of this extraordinary chorus 133 00:12:23,880 --> 00:12:27,600 by working out who is making which noise. 134 00:12:30,520 --> 00:12:33,480 One fish is especially talkative. 135 00:12:36,360 --> 00:12:39,440 It's perhaps the reef's most famous resident. 136 00:12:40,560 --> 00:12:42,040 The clownfish. 137 00:12:44,720 --> 00:12:46,520 While filming for the series, 138 00:12:46,600 --> 00:12:50,840 we followed this particular family of saddleback clownfish 139 00:12:50,920 --> 00:12:54,160 as they search for a suitable place to lay their eggs. 140 00:12:57,640 --> 00:13:00,000 It's a noisy affair. 141 00:13:14,800 --> 00:13:17,040 For clownfish sound really is everything. 142 00:13:17,120 --> 00:13:19,600 They spend all day talking to each other. 143 00:13:20,360 --> 00:13:22,160 You've got dominance and submission. 144 00:13:22,240 --> 00:13:24,400 You've got all the others calling to each other. 145 00:13:26,120 --> 00:13:29,080 It seems that they also use sound 146 00:13:30,240 --> 00:13:35,000 in protecting themselves from the many predators that hunt around the reef. 147 00:13:40,920 --> 00:13:43,520 Including coral trout. 148 00:13:57,360 --> 00:14:01,080 Will this model trout fool the clownfish? 149 00:14:07,480 --> 00:14:10,040 They react almost immediately. 150 00:14:12,600 --> 00:14:14,080 By mimicking a predator, 151 00:14:14,160 --> 00:14:19,200 Steve manages to record their alarm calls without putting them at risk. 152 00:14:20,160 --> 00:14:23,480 You can really hear the deeper pulsing sound of the female 153 00:14:23,560 --> 00:14:26,000 as she tries to scare the coral trout away. 154 00:14:27,760 --> 00:14:30,120 And all the little ones are just popping... Pop, pop, pop. 155 00:14:30,200 --> 00:14:32,480 As if to say, "I'm still okay. I'm still alive." 156 00:14:34,320 --> 00:14:37,520 So they've got this real language of sounds that they're using 157 00:14:37,600 --> 00:14:40,760 just to try and defend the colony against this coral trout. 158 00:14:44,120 --> 00:14:47,760 But that discovery has led to a serious worry. 159 00:14:50,880 --> 00:14:54,040 The fish were really popping away at the predator. 160 00:14:54,120 --> 00:14:57,720 But as soon as the boat came over they looked completely distracted. 161 00:14:57,800 --> 00:15:00,800 With all that noise it completely changed how the fish were behaving. 162 00:15:02,480 --> 00:15:05,680 Unable to make themselves heard above the noise of boats, 163 00:15:05,760 --> 00:15:08,400 the family can't warn each other of danger. 164 00:15:08,480 --> 00:15:11,320 And so they are now vulnerable to attack. 165 00:15:12,600 --> 00:15:14,600 You think about how many boats are driving around. 166 00:15:14,680 --> 00:15:17,560 All of the ships, all of the offshore drilling. 167 00:15:17,640 --> 00:15:19,400 All the noise that we're making in the ocean 168 00:15:19,480 --> 00:15:21,400 you realise just how much we're drowning out 169 00:15:21,480 --> 00:15:23,400 this natural biological noise, 170 00:15:23,480 --> 00:15:27,440 robbing animals of their ability to be able to talk to each other. 171 00:15:31,240 --> 00:15:35,840 All this noise may have serious consequences for many reef fish 172 00:15:35,920 --> 00:15:40,080 because their babies, as soon as they hatch are swept out to sea. 173 00:15:44,000 --> 00:15:47,760 There they feed and grow until strong enough to swim back. 174 00:15:49,720 --> 00:15:53,640 And to find the reef, they use sound. 175 00:15:54,720 --> 00:15:57,680 They listen in. They eavesdrop to the noises that they can hear 176 00:15:57,760 --> 00:16:00,960 and they use that to choose which reef they want to make their home. 177 00:16:01,160 --> 00:16:03,720 But obviously because we're adding all this noise to the ocean 178 00:16:03,800 --> 00:16:06,200 it's a wonder whether they can even hear the reef at all. 179 00:16:11,400 --> 00:16:15,000 Man-made noise is now everywhere in the ocean. 180 00:16:15,120 --> 00:16:18,760 And it has an effect on marine creatures of all kinds. 181 00:16:20,880 --> 00:16:22,840 From tiny fish 182 00:16:24,480 --> 00:16:26,840 to gigantic whales. 183 00:16:30,040 --> 00:16:33,160 But Steve believes there are solutions. 184 00:16:33,800 --> 00:16:36,360 Noise in the ocean is a real problem. 185 00:16:36,440 --> 00:16:38,560 But, it's something that we can control. 186 00:16:38,640 --> 00:16:40,160 We can choose where we make the noise. 187 00:16:40,240 --> 00:16:42,160 We can choose when we make the noise. 188 00:16:42,240 --> 00:16:45,600 We can directly reduce the amount of noise that we make 189 00:16:45,680 --> 00:16:47,480 and we can start doing that today. 190 00:16:55,480 --> 00:16:57,720 We're only now beginning to realise 191 00:16:57,800 --> 00:17:01,880 what an impact our noise is having on the inhabitants of the ocean. 192 00:17:04,880 --> 00:17:08,040 Other forms of pollution are only too familiar. 193 00:17:15,040 --> 00:17:17,720 Since its invention some hundred years ago, 194 00:17:17,800 --> 00:17:21,680 plastic has become an integral part of our daily lives. 195 00:17:21,760 --> 00:17:25,400 But every year, some eight million tonnes of it 196 00:17:25,480 --> 00:17:27,360 ends up in the ocean. 197 00:17:27,440 --> 00:17:29,680 And there, it could be lethal. 198 00:17:34,960 --> 00:17:37,240 While filming Blue Planet II, 199 00:17:37,320 --> 00:17:40,720 the crews found plastic in every ocean. 200 00:17:42,200 --> 00:17:45,400 Even in the most remote locations. 201 00:17:49,920 --> 00:17:51,360 South Georgia. 202 00:17:53,440 --> 00:17:55,880 900 miles north of Antarctica, 203 00:17:55,960 --> 00:17:59,160 this isolated wilderness is the breeding place 204 00:17:59,240 --> 00:18:02,840 for vast numbers of penguins and elephant seals. 205 00:18:12,960 --> 00:18:15,520 It's also a favourite nesting site 206 00:18:15,600 --> 00:18:17,680 for the largest bird in the sky. 207 00:18:19,720 --> 00:18:21,640 A wandering albatross. 208 00:18:25,080 --> 00:18:27,640 Here we learn of the extraordinary lengths 209 00:18:27,720 --> 00:18:32,320 ancient parents go to give their chicks the best chance of survival. 210 00:18:35,080 --> 00:18:39,800 Each devoted parent travels thousands of miles searching for fish and squid 211 00:18:39,880 --> 00:18:41,800 to feed their hungry chick. 212 00:18:45,280 --> 00:18:47,200 But despite all their efforts, 213 00:18:47,280 --> 00:18:50,280 the albatross colony here is in trouble. 214 00:18:52,120 --> 00:18:56,400 Lucy Quinn is part of the British Antarctic Survey team 215 00:18:56,480 --> 00:18:59,960 studying the birds here for the last 40 years. 216 00:19:01,120 --> 00:19:03,240 Its only through looking at long terms studies 217 00:19:03,320 --> 00:19:05,760 that you get a sense of these creatures. 218 00:19:05,840 --> 00:19:10,960 And the albatrosses here have, over the past 10 years, been in decline. 219 00:19:12,440 --> 00:19:15,480 There are a number of possible reasons. 220 00:19:15,560 --> 00:19:17,320 While foraging at sea, 221 00:19:17,400 --> 00:19:21,360 albatross can get entangled and drowned by fishing gear. 222 00:19:23,120 --> 00:19:25,840 But Lucy is particularly alarmed 223 00:19:25,920 --> 00:19:28,960 by what the parents are bringing back for their chick. 224 00:19:29,240 --> 00:19:31,840 Albatrosses have the ability to cough up 225 00:19:31,920 --> 00:19:34,240 bits of food that they can't digest. 226 00:19:34,320 --> 00:19:37,160 And from that we can tell what they've been eating. 227 00:19:38,080 --> 00:19:42,240 A healthy albatross chick in its diet should really have things like squid. 228 00:19:42,320 --> 00:19:46,080 So we can find the squid beaks that come out of the pellet. 229 00:19:46,160 --> 00:19:49,720 And also things like fish so we can find fish bones as well. 230 00:19:51,960 --> 00:19:56,520 But these chicks are being fed something very different. 231 00:19:57,320 --> 00:20:02,360 We have some plastic that this poor chick has had to bring up. 232 00:20:03,600 --> 00:20:04,960 Plastic bag. 233 00:20:08,040 --> 00:20:11,160 Here we have some food packaging. Looks like rice. 234 00:20:11,960 --> 00:20:16,160 Luckily for this chick, he has managed to get this out of his stomach. 235 00:20:16,240 --> 00:20:19,360 So, fingers crossed he doesn't have any more plastic left in there 236 00:20:19,440 --> 00:20:20,640 before he fledges. 237 00:20:24,040 --> 00:20:27,720 For other chicks, plastic can be fatal. 238 00:20:29,640 --> 00:20:32,360 Unfortunately, there is a plastic toothpick 239 00:20:32,440 --> 00:20:34,560 that have actually gone through the stomach. 240 00:20:34,640 --> 00:20:39,000 Something just as small as that has actually has managed to kill the bird. 241 00:20:39,080 --> 00:20:40,680 It's really sad to see. 242 00:20:43,120 --> 00:20:48,200 Lucy collects and records what plastic she finds around the nests. 243 00:20:51,280 --> 00:20:56,280 These are items that were regurgitated just from last season. 244 00:20:56,360 --> 00:20:59,320 And that's gonna be a vast underestimation 245 00:20:59,400 --> 00:21:02,240 because that's just ones that we happen to find. 246 00:21:02,320 --> 00:21:06,000 There'll be many more that we never see being brought back. 247 00:21:09,160 --> 00:21:12,080 To find out where all this rubbish is coming from, 248 00:21:12,160 --> 00:21:17,640 Lucy and her team have attached GPS trackers to adult birds. 249 00:21:23,120 --> 00:21:25,800 It's showing where they're going to find food for themselves 250 00:21:25,880 --> 00:21:28,440 and to find food to bring back for their chicks. 251 00:21:29,400 --> 00:21:32,240 It really shows us that they could be picking up plastic 252 00:21:32,320 --> 00:21:34,720 from thousands of miles away. 253 00:21:35,480 --> 00:21:38,280 Plastics coming from either being dumped at sea 254 00:21:38,360 --> 00:21:40,960 or also from people's homes. 255 00:21:41,040 --> 00:21:44,760 Plastic gets into the rivers and then the rivers flow into the sea. 256 00:21:45,360 --> 00:21:48,920 So this isn't just a problem around these remote parts. 257 00:21:49,000 --> 00:21:51,000 This is happening worldwide. 258 00:21:51,080 --> 00:21:53,760 And it's our rubbish that's going into the oceans. 259 00:21:53,840 --> 00:21:56,320 It's our problem that we need to solve. 260 00:22:01,040 --> 00:22:02,920 In some parts of the ocean, 261 00:22:03,000 --> 00:22:08,080 it's estimated that there are now over one million pieces of plastic 262 00:22:08,160 --> 00:22:09,840 for every square mile. 263 00:22:11,160 --> 00:22:12,920 And we're only beginning to discover 264 00:22:13,000 --> 00:22:16,440 just how seriously that affects marine life. 265 00:22:24,040 --> 00:22:26,800 On the east coast of the United States, 266 00:22:26,880 --> 00:22:31,960 researchers are investigating the mysterious deaths of young dolphins. 267 00:22:41,000 --> 00:22:44,480 The team is led by Dr Leslie Hart. 268 00:22:45,600 --> 00:22:47,840 It looks to be a young animal. 269 00:22:47,920 --> 00:22:49,680 Maybe a little bit over a year. 270 00:22:49,760 --> 00:22:53,080 So we're gonna try to find out more information on why this dolphin died. 271 00:23:01,440 --> 00:23:03,840 Looking at young dolphins... 272 00:23:03,920 --> 00:23:06,640 The very young dolphins, it's always heart-breaking. 273 00:23:14,360 --> 00:23:17,080 Leslie takes tissue samples. 274 00:23:17,760 --> 00:23:21,360 Their chemical analysis could provide crucial evidence. 275 00:23:22,400 --> 00:23:26,520 We are often shocked by the high levels of toxins 276 00:23:26,600 --> 00:23:28,400 that we detect in these animals. 277 00:23:29,920 --> 00:23:33,200 These young calves are dying for a number of reasons. 278 00:23:33,280 --> 00:23:37,280 But we suspect man-made toxins are playing a large role. 279 00:23:39,840 --> 00:23:42,600 And plastic could be part of the problem. 280 00:23:52,720 --> 00:23:54,280 Once in the ocean, 281 00:23:54,360 --> 00:23:57,440 plastic breaks down into tiny fragments. 282 00:23:58,320 --> 00:24:00,160 Micro plastics. 283 00:24:03,400 --> 00:24:07,440 Along with all the industrial chemicals that have drained into the ocean 284 00:24:07,520 --> 00:24:10,600 these form a potentially toxic soup. 285 00:24:16,840 --> 00:24:18,760 The really small organisms 286 00:24:18,840 --> 00:24:22,240 can mistake these tiny, tiny plastics as food. 287 00:24:22,320 --> 00:24:25,000 Then the larger organisms eat the plankton. 288 00:24:25,080 --> 00:24:27,640 Then the larger fish eat the smaller fish, 289 00:24:27,720 --> 00:24:29,160 and so on and so forth. 290 00:24:31,200 --> 00:24:34,400 Dolphins are at the top of this food chain 291 00:24:34,480 --> 00:24:38,040 and it's now thought that pollutants may be building up in their tissues 292 00:24:38,120 --> 00:24:43,760 to such a degree that a mother's contaminated milk could kill her calf. 293 00:25:01,840 --> 00:25:06,200 Industrial pollution and the discarding of plastic waste 294 00:25:06,280 --> 00:25:10,600 must be tackled for the sake of all life in the ocean. 295 00:25:26,440 --> 00:25:30,120 Around the world, people are now devoting their lives 296 00:25:30,200 --> 00:25:33,400 to saving some of the most threatened sea creatures. 297 00:25:35,480 --> 00:25:38,080 As here in the Caribbean. 298 00:25:41,760 --> 00:25:44,640 Every year on just a few islands, 299 00:25:44,720 --> 00:25:47,360 a remarkable event takes place. 300 00:25:57,120 --> 00:25:59,680 As the sun sets, 301 00:25:59,760 --> 00:26:02,760 giant reptiles begin to emerge. 302 00:26:17,040 --> 00:26:20,640 This magnificent creature preparing... 303 00:26:20,720 --> 00:26:22,680 Whoops. 304 00:26:22,760 --> 00:26:25,200 Preparing to lay her eggs 305 00:26:25,280 --> 00:26:28,160 is the largest of all turtles. 306 00:26:28,240 --> 00:26:29,600 A leatherback. 307 00:26:30,520 --> 00:26:34,320 They can grow up to half a tonne in weight. 308 00:26:34,400 --> 00:26:38,240 And they have an ancestry that goes back a hundred million years 309 00:26:38,320 --> 00:26:40,320 to the age of the dinosaur. 310 00:26:41,560 --> 00:26:46,680 But in recent times their numbers have fallen catastrophically. 311 00:26:47,680 --> 00:26:51,840 Here, however, in the Caribbean there is hope. 312 00:26:56,480 --> 00:26:58,880 Leatherback turtles leave the sea 313 00:26:58,960 --> 00:27:02,120 in order to lay their eggs in the dry sand. 314 00:27:04,520 --> 00:27:09,480 But out of water, these huge creatures are easy targets for hunters. 315 00:27:13,200 --> 00:27:16,000 In a small fishing village in Trinidad, 316 00:27:16,080 --> 00:27:19,920 Len Peters has experienced this first hand. 317 00:27:21,200 --> 00:27:25,600 I grew up in a household where the presence of turtle meat was normal. 318 00:27:25,680 --> 00:27:27,480 The fridge was always full of it. 319 00:27:27,560 --> 00:27:30,600 Everybody... Everybody harvested turtles, including my parents. 320 00:27:31,560 --> 00:27:34,040 It's only when I became exposed to things 321 00:27:34,120 --> 00:27:35,920 that were being published about leatherbacks 322 00:27:36,000 --> 00:27:37,440 who were on the verge of extinction. 323 00:27:37,520 --> 00:27:39,080 And nobody cares. 324 00:27:39,160 --> 00:27:40,640 That piqued my interest. 325 00:27:41,680 --> 00:27:45,720 Len took the leatherback's future into his own hands. 326 00:27:47,600 --> 00:27:51,440 He began patrolling the beach at night to protect the turtles. 327 00:27:52,000 --> 00:27:53,640 A brave thing to do. 328 00:27:57,360 --> 00:28:00,160 We were met with tremendous resistance. 329 00:28:00,240 --> 00:28:02,000 People would pelt us at night. 330 00:28:02,080 --> 00:28:04,240 I have had persons insult me. 331 00:28:04,320 --> 00:28:05,880 I've had persons curse me. 332 00:28:05,960 --> 00:28:10,680 I've had persons physically try to wrestle me with a machete. 333 00:28:10,760 --> 00:28:13,400 So it was really a hostile time back then. 334 00:28:13,480 --> 00:28:16,200 If Len was going to save these turtles 335 00:28:16,280 --> 00:28:19,040 he needed to win over the whole community. 336 00:28:21,240 --> 00:28:25,480 We had to find a way to get the villagers to benefit 337 00:28:25,560 --> 00:28:27,600 from the presence of these animals. 338 00:28:30,720 --> 00:28:34,440 He began to encourage tourists to visit the beach 339 00:28:34,520 --> 00:28:37,440 and trained some villagers to be their guides. 340 00:28:41,560 --> 00:28:44,120 To help secure the turtles' future, 341 00:28:44,200 --> 00:28:47,280 he took the message to the next generation. 342 00:28:47,840 --> 00:28:51,840 Now what's... What's the largest size a leatherback can grow to? 343 00:28:52,200 --> 00:28:54,280 Uh, Shanie. 344 00:28:54,560 --> 00:28:56,440 - 2,000 pounds. - That's correct. 345 00:28:56,520 --> 00:29:00,280 Leatherbacks can grow to 2,000 pounds. 346 00:29:00,360 --> 00:29:01,920 Well, that's a big turtle. 347 00:29:02,560 --> 00:29:04,600 Len's hard work paid off. 348 00:29:04,680 --> 00:29:07,000 And now, attitudes have changed. 349 00:29:10,760 --> 00:29:14,280 It took us a while to reach out to the villagers. 350 00:29:14,360 --> 00:29:16,800 But gradually we got them involved as well. 351 00:29:16,880 --> 00:29:19,840 We got some of the poachers who would be hunting the animals to 352 00:29:20,040 --> 00:29:21,800 be part of the conservation programme. 353 00:29:24,440 --> 00:29:26,920 As well as protecting the adult turtles, 354 00:29:27,000 --> 00:29:31,280 the team also collect any eggs that might be flooded at high tide. 355 00:29:34,320 --> 00:29:37,160 If the eggs are laid too close to the sea, 356 00:29:37,240 --> 00:29:39,840 we relocate the eggs and rebury them. 357 00:29:41,200 --> 00:29:43,800 Thanks to the efforts of this community, 358 00:29:43,880 --> 00:29:47,400 these turtles have had an extraordinary change in fortune. 359 00:29:49,600 --> 00:29:52,120 This is now thought to be one of the densest 360 00:29:52,200 --> 00:29:55,000 leatherback nesting beaches in the world. 361 00:29:58,880 --> 00:30:02,400 When we started at the height of the nesting season, 362 00:30:02,480 --> 00:30:06,160 the numbers will be 30-40 turtles a night. 363 00:30:06,240 --> 00:30:07,960 Now, it's over 500. 364 00:30:08,080 --> 00:30:11,360 So, we have seen an increase from 40 turtles 365 00:30:11,440 --> 00:30:14,400 to 500 turtles a night in just around 20 years. 366 00:30:18,040 --> 00:30:21,800 Precious new hatchlings are also given a helping hand. 367 00:30:25,360 --> 00:30:28,440 Any that emerge during the day are collected 368 00:30:28,520 --> 00:30:33,240 to be released safely back to the sea, away from hungry birds. 369 00:30:40,400 --> 00:30:45,040 This little leatherback will have to face a thousand hazards 370 00:30:45,120 --> 00:30:49,480 before it returns as an adult to this beach where it hatched. 371 00:30:50,360 --> 00:30:53,560 And those dangers will be greatly increased 372 00:30:53,640 --> 00:30:56,840 because of damage that we have done to the ocean. 373 00:30:58,760 --> 00:31:00,200 Good luck, little leatherback. 374 00:31:31,680 --> 00:31:34,040 Protecting breeding sites on beaches 375 00:31:34,120 --> 00:31:38,560 may improve the fortune of some marine animals, 376 00:31:38,640 --> 00:31:42,800 but safeguarding them while they roam the high seas is much more difficult. 377 00:31:47,800 --> 00:31:50,720 Out here, there is little protection. 378 00:31:59,560 --> 00:32:05,600 Every night, thousands of miles of fishing lines laden with hooks are set. 379 00:32:07,960 --> 00:32:11,280 There's enough, it's said, to wrap twice around the world. 380 00:32:16,240 --> 00:32:19,520 Nets large enough to engulf cathedrals 381 00:32:19,600 --> 00:32:22,840 trap hundreds of tonnes of fish at a time. 382 00:32:25,520 --> 00:32:30,000 Long distance travellers such as sharks are particularly at risk. 383 00:32:36,280 --> 00:32:40,560 It's estimated that tens of millions are killed every year, 384 00:32:40,640 --> 00:32:45,440 including the biggest fish in the sea, the whale shark. 385 00:32:57,480 --> 00:33:01,160 Shark biologist Jonathan Green is concerned 386 00:33:01,240 --> 00:33:04,640 that time is running out for these extraordinary creatures. 387 00:33:05,840 --> 00:33:08,560 We know that they're being fished possibly at a massive rate. 388 00:33:09,040 --> 00:33:12,480 They may be taken by the thousands, possibly tens of thousands a year. 389 00:33:13,160 --> 00:33:14,880 If that is indeed true, 390 00:33:14,960 --> 00:33:18,440 we don't know how long they can withstand that kind of fishing pressure. 391 00:33:20,240 --> 00:33:23,160 To save them, Jonathan is trying to solve 392 00:33:23,240 --> 00:33:25,880 the mystery of where they give birth. 393 00:33:31,960 --> 00:33:36,320 And, for the first time, he has a clue as to where this might be. 394 00:33:43,600 --> 00:33:47,680 Pregnant whale sharks are thought to be travelling from across the Pacific Ocean 395 00:33:47,760 --> 00:33:50,480 to Darwin Island in the Galapagos. 396 00:33:59,160 --> 00:34:01,360 Jonathan is going to try and attach 397 00:34:01,440 --> 00:34:04,920 a multi-sensor camera tag to a pregnant female. 398 00:34:05,880 --> 00:34:07,280 Okay. We're good to go. 399 00:34:15,840 --> 00:34:19,000 These sharks only stay in the area for a few days. 400 00:34:19,960 --> 00:34:21,880 This may be his only chance. 401 00:34:34,160 --> 00:34:39,520 Jonathan has to attach the tag before the shark dives to dangerous depths. 402 00:34:58,680 --> 00:35:02,000 The tag will remain on the giant's fin for two days 403 00:35:02,080 --> 00:35:04,160 before it's automatically released. 404 00:35:06,840 --> 00:35:10,760 Once retrieved, it reveals some unusual behaviour. 405 00:35:13,440 --> 00:35:14,920 Oh, beautiful, beautiful. 406 00:35:17,480 --> 00:35:21,840 There's a silky rubbing up against the front. Next to her right. 407 00:35:22,240 --> 00:35:25,960 The silky sharks are brushing up against her rough skin, 408 00:35:26,040 --> 00:35:28,320 perhaps to scrape off parasites. 409 00:35:30,160 --> 00:35:34,920 These predatory sharks make the surface waters very unsafe places 410 00:35:35,000 --> 00:35:37,200 for young fish of any kind. 411 00:35:40,080 --> 00:35:42,280 There is a surprise in store. 412 00:35:44,000 --> 00:35:47,000 The tag's depth sensor reveals that she dived 413 00:35:47,080 --> 00:35:49,720 to a depth of 600 metres. 414 00:35:51,880 --> 00:35:55,320 But down there, it's too dark for the camera. 415 00:36:01,560 --> 00:36:04,800 The only way Jonathan can prove if they're giving birth 416 00:36:05,680 --> 00:36:07,480 is to go down and look. 417 00:36:31,000 --> 00:36:34,800 Out of the gloom, a shape materialises. 418 00:36:37,360 --> 00:36:39,440 Another massive whale shark. 419 00:36:41,320 --> 00:36:44,480 Oh, look at her. She's having a look at us. She's looking right at us. 420 00:36:49,600 --> 00:36:51,640 She is huge. 421 00:36:51,760 --> 00:36:54,160 And look at the belly. Absolutely massive. 422 00:36:55,440 --> 00:36:57,200 That's a large pregnant female. 423 00:36:58,160 --> 00:37:00,120 She's turning around. She's turning around. 424 00:37:06,200 --> 00:37:08,960 Goes to show we can follow them. We can follow them in the submarine. 425 00:37:12,840 --> 00:37:15,880 She leads them down into the darkness. 426 00:37:18,720 --> 00:37:22,720 Rover control. Passing 100 metres, descending. 427 00:37:25,200 --> 00:37:28,800 Heading down. I think she's accelerated slightly. 428 00:37:32,520 --> 00:37:34,320 She's too fast. 429 00:37:35,360 --> 00:37:39,320 And with the strong current running against them, the sub can't keep up. 430 00:37:44,040 --> 00:37:47,680 But, for the first time, Jonathan can see for himself 431 00:37:47,760 --> 00:37:49,600 exactly where she's headed. 432 00:37:52,240 --> 00:37:54,320 What specifically Darwin could provide 433 00:37:54,400 --> 00:37:59,160 is a safe refuge for those new-born pups where predators can't access. 434 00:38:00,920 --> 00:38:03,560 Perfect conditions for the formative years 435 00:38:03,640 --> 00:38:05,480 of these ocean-travelling giants. 436 00:38:13,360 --> 00:38:14,960 That was unbelievable. 437 00:38:16,600 --> 00:38:18,360 Dream of a lifetime. 438 00:38:21,080 --> 00:38:23,240 His discovery that pregnant whale sharks 439 00:38:23,320 --> 00:38:26,280 are visiting this very deep patch of the sea floor 440 00:38:26,360 --> 00:38:30,520 is strong evidence that this is indeed where the giants produce their young. 441 00:38:33,280 --> 00:38:36,680 If I can actually prove that they are giving birth in this area, 442 00:38:36,760 --> 00:38:38,840 then we'll have the information necessary 443 00:38:38,920 --> 00:38:40,920 to go to governments and actually say, 444 00:38:41,000 --> 00:38:44,200 "You must preserve those routes that they're migrating through." 445 00:38:44,280 --> 00:38:47,640 And then, and only then, can we really truly afford protection 446 00:38:47,720 --> 00:38:49,800 for this beautiful ocean traveller. 447 00:38:57,680 --> 00:38:59,840 Today, less than one percent 448 00:38:59,920 --> 00:39:02,600 of our international waters are protected. 449 00:39:05,480 --> 00:39:08,880 And the creation of marine reserves is vital 450 00:39:08,960 --> 00:39:12,920 if we're to safeguard the future of many ocean creatures. 451 00:39:18,800 --> 00:39:21,440 It will require international cooperation. 452 00:39:22,880 --> 00:39:24,800 But here, too, there is hope. 453 00:39:27,120 --> 00:39:29,280 We can turn things around. 454 00:39:30,000 --> 00:39:31,960 We've done so once before. 455 00:39:32,880 --> 00:39:36,640 For centuries, the sea-going nations of the world 456 00:39:36,720 --> 00:39:39,680 hunted the great whales until they were close to extinction. 457 00:39:40,560 --> 00:39:44,840 And then, in 1986, those nations got together 458 00:39:44,920 --> 00:39:48,800 and agreed to put a stop to commercial whaling. 459 00:39:52,560 --> 00:39:56,320 Today, although a few nations continue to hunt whales, 460 00:39:56,400 --> 00:39:59,160 some of the great whales are making a recovery. 461 00:40:07,520 --> 00:40:10,280 In the tropical seas surrounding Sri Lanka, 462 00:40:10,360 --> 00:40:13,840 there are stories of vast gatherings of whales. 463 00:40:18,000 --> 00:40:21,480 When the civil war ended in 2009, 464 00:40:21,560 --> 00:40:25,440 locals here were able once again to fish these waters. 465 00:40:28,200 --> 00:40:31,720 There were soon reports of assemblies of sperm whales, 466 00:40:31,800 --> 00:40:34,960 the likes of which had not been seen for centuries. 467 00:40:37,160 --> 00:40:41,120 Marine guide Daya was determined to get to the truth 468 00:40:41,200 --> 00:40:43,520 behind these fishermen's tales. 469 00:40:44,480 --> 00:40:46,720 The fishermen told me that there are lots of whales 470 00:40:46,800 --> 00:40:48,000 a little bit north from here. 471 00:40:48,920 --> 00:40:51,320 They didn't actually tell me a number, 472 00:40:51,400 --> 00:40:54,760 but in big numbers, not one or twos. 473 00:40:54,840 --> 00:40:56,800 Er, many. 474 00:41:01,280 --> 00:41:03,600 It took him three years, 475 00:41:03,680 --> 00:41:08,240 but eventually, he found evidence to support these rumours. 476 00:41:54,720 --> 00:41:58,000 We saw about 15 sperm whales go past us. 477 00:42:07,760 --> 00:42:09,800 Then, another four came past us. 478 00:42:13,160 --> 00:42:16,600 After about 40 then passed me, I started counting. 479 00:42:21,640 --> 00:42:24,080 Still, they kept coming, so I lost count. 480 00:42:26,440 --> 00:42:29,480 I estimated that we saw about 300 sperm whales. 481 00:42:37,000 --> 00:42:40,960 Sperm whales were once killed in vast numbers 482 00:42:41,080 --> 00:42:43,880 and it's thought that if the slaughter had continued, 483 00:42:43,960 --> 00:42:47,360 the species would be in danger of extermination. 484 00:42:50,640 --> 00:42:55,360 But now, here at least, they are being seen in huge numbers. 485 00:42:56,840 --> 00:43:00,680 I believe they come here to feed, mate, and raise their young. 486 00:43:00,800 --> 00:43:03,320 So, this must be a holiday spot for them, you know. 487 00:43:03,640 --> 00:43:06,960 At the moment, I don't know of any other place in the world 488 00:43:07,040 --> 00:43:09,760 that, er, sperm whales gather like this. 489 00:43:13,160 --> 00:43:16,800 Although some whale populations are still in decline, 490 00:43:16,880 --> 00:43:21,600 scenes like this prove that when sea-going nations come together, 491 00:43:21,680 --> 00:43:24,720 they can achieve astonishing results. 492 00:43:32,600 --> 00:43:38,080 But today, the oceans face threats on a truly global scale. 493 00:43:43,840 --> 00:43:45,800 The Great Barrier Reef. 494 00:43:48,240 --> 00:43:51,680 The largest coral reef system in the world. 495 00:43:54,360 --> 00:43:59,640 Here, we filmed stories which reveal just how smart fish can be. 496 00:44:05,320 --> 00:44:08,080 This ingenious tuskfish, for example, 497 00:44:08,160 --> 00:44:12,560 used a favourite coral anvil to smash open shellfish. 498 00:44:14,840 --> 00:44:18,320 This astonishing behaviour has been closely studied 499 00:44:18,400 --> 00:44:20,840 by local scientist Alex Vail. 500 00:44:22,600 --> 00:44:25,080 We're calling Percy "Percy the Persistent" 501 00:44:26,400 --> 00:44:29,600 because he took, like, an hour to open the first shell. 502 00:44:35,040 --> 00:44:37,440 He must have hit it well over 50 times, 503 00:44:37,520 --> 00:44:40,400 but he just kept on going and finally got it open. 504 00:44:49,840 --> 00:44:52,880 Alex grew up on the Great Barrier Reef 505 00:44:52,960 --> 00:44:55,760 on one of its more remote islands, Lizard. 506 00:44:58,120 --> 00:45:00,400 He knows the reef intimately. 507 00:45:05,720 --> 00:45:09,480 But, in 2016, while he was filming for Blue Planet II, 508 00:45:09,560 --> 00:45:12,080 Alex witnessed a catastrophe. 509 00:45:14,040 --> 00:45:16,920 When we started filming, everything was pretty much fine. 510 00:45:17,000 --> 00:45:19,080 All of the corals were basically healthy. 511 00:45:21,200 --> 00:45:24,480 But in the last few weeks, everything changed. 512 00:45:25,520 --> 00:45:28,240 I have never seen anything like this before. 513 00:45:31,440 --> 00:45:33,600 A combination of a warming ocean 514 00:45:33,680 --> 00:45:37,280 and an unpredictable weather event called El NiƱo 515 00:45:37,360 --> 00:45:40,000 raised sea temperatures to record levels. 516 00:45:45,000 --> 00:45:48,280 And this had a disastrous effect on the corals. 517 00:45:49,800 --> 00:45:54,040 The heat causes reef-building corals to lose their nourishing algae, 518 00:45:55,040 --> 00:45:57,560 exposing their white skeletons. 519 00:46:02,440 --> 00:46:06,560 When temperatures remain high, bleached corals die off. 520 00:46:09,440 --> 00:46:12,400 The bleaching this year has been the worst in history 521 00:46:12,480 --> 00:46:13,920 for the Great Barrier Reef. 522 00:46:14,000 --> 00:46:16,440 About 90 percent of the branching corals 523 00:46:16,520 --> 00:46:18,880 on the reef out here at Lizard Island are dead. 524 00:46:21,840 --> 00:46:24,520 It also has disastrous consequences 525 00:46:24,600 --> 00:46:26,760 for the other creatures that live here. 526 00:46:30,320 --> 00:46:33,000 Percy swimming around out there. 527 00:46:33,120 --> 00:46:36,080 The really sad thing is that his castle's starting to bleach. 528 00:46:37,360 --> 00:46:40,600 If we lose our coral, there's a chance we're going to lose our tuskfish. 529 00:46:42,560 --> 00:46:46,160 It's incredibly sad to see areas that you've dived on 530 00:46:46,240 --> 00:46:49,440 since you were a little kid just turn to rubble. 531 00:46:52,600 --> 00:46:54,720 I cried in my mask, when I saw, 532 00:46:54,800 --> 00:46:56,920 you know, some of the devastation from this bleaching. 533 00:47:04,840 --> 00:47:06,720 In the last three years, 534 00:47:06,800 --> 00:47:09,720 over two-thirds of the world's coral reefs 535 00:47:09,840 --> 00:47:13,520 are thought to have suffered from rises in ocean temperatures. 536 00:47:26,320 --> 00:47:28,680 This is not the only challenge they face. 537 00:47:31,360 --> 00:47:33,800 Research is revealing how the fundamental 538 00:47:33,880 --> 00:47:36,160 chemistry of the ocean is changing. 539 00:47:39,680 --> 00:47:42,880 Professor Chris Langdon shows me what this might mean 540 00:47:42,960 --> 00:47:47,840 for the future of our seas by pouring dilute acid over shells. 541 00:47:52,840 --> 00:47:56,480 And how much more acidic is this than the present ocean? 542 00:47:57,120 --> 00:48:00,600 This is more concentrated than the pH of the ocean 543 00:48:01,200 --> 00:48:04,480 but it accelerates the process so we can see something visually. 544 00:48:05,000 --> 00:48:08,280 So, what's happening is, these shells, they're made out of calcium carbonate, 545 00:48:09,000 --> 00:48:10,560 and the acid is dissolving them. 546 00:48:11,160 --> 00:48:14,920 And coral reefs are made out of the same material as these shells here. 547 00:48:15,840 --> 00:48:19,840 But surely this is not happening in the ocean now. Right now? 548 00:48:19,920 --> 00:48:23,400 What we're seeing here is more dramatic than what's happening in the ocean. 549 00:48:23,480 --> 00:48:28,160 But the shells and the reefs are really truly dissolving. 550 00:48:28,240 --> 00:48:31,360 Coral reefs could be gone by the end of this century. 551 00:48:34,560 --> 00:48:38,040 And the cause of this? Carbon dioxide. 552 00:48:39,800 --> 00:48:43,280 Dissolved in the sea water, it forms carbonic acid. 553 00:48:44,200 --> 00:48:46,720 The more carbon dioxide in the atmosphere, 554 00:48:46,800 --> 00:48:49,120 the more acidic the ocean becomes. 555 00:48:51,320 --> 00:48:54,120 Evidence points to the burning of fossil fuels 556 00:48:54,240 --> 00:48:58,800 as the primary cause for these increasing levels of carbon dioxide. 557 00:49:00,640 --> 00:49:03,200 And this is man-made beyond question. 558 00:49:03,280 --> 00:49:04,480 Beyond question. 559 00:49:08,600 --> 00:49:11,680 But Chris believes all is not lost. 560 00:49:13,200 --> 00:49:17,160 All we have to do, and I say all, is reduce our CO2 emissions. 561 00:49:17,240 --> 00:49:21,360 We can switch to renewable fuels, wind and solar, 562 00:49:21,440 --> 00:49:23,400 instead of natural fossil fuels. 563 00:49:23,480 --> 00:49:25,160 And so, none of this has to 564 00:49:26,080 --> 00:49:28,480 - develop to the worst case. - And that could fix it? 565 00:49:28,560 --> 00:49:33,160 Yeah, absolutely. So, this future does not have to play out. It's up to us. 566 00:49:44,080 --> 00:49:47,680 As the climate changes, the seas warm. 567 00:49:47,800 --> 00:49:50,680 Our oceans are being seriously affected. 568 00:49:53,240 --> 00:49:57,560 And this is nowhere more apparent than at the poles. 569 00:50:06,520 --> 00:50:08,120 Antarctica. 570 00:50:12,040 --> 00:50:16,560 For the Blue Planet II team, this was their most ambitious expedition. 571 00:50:19,240 --> 00:50:23,120 For the first time in history, a manned submersible 572 00:50:23,200 --> 00:50:26,680 will try to dive to a depth of 1,000 metres 573 00:50:26,760 --> 00:50:29,160 and reach the Antarctic seabed. 574 00:50:30,560 --> 00:50:33,360 A true journey into the unknown. 575 00:50:49,960 --> 00:50:53,240 Control rover. Passing 40 metres. Over. 576 00:50:59,280 --> 00:51:02,240 Leading the team on this historic dive 577 00:51:02,320 --> 00:51:04,560 is deep sea scientist John Copley. 578 00:51:12,360 --> 00:51:15,920 We get our first glimpse of this landscape. 579 00:51:18,640 --> 00:51:22,280 And the carpet of life around us is astounding. 580 00:51:23,040 --> 00:51:24,320 It's beautiful. 581 00:51:33,280 --> 00:51:38,000 Diving in a submersible gives John an entirely new understanding 582 00:51:38,080 --> 00:51:40,760 of how this rich ecosystem works. 583 00:51:42,480 --> 00:51:45,560 But it also offers him a unique opportunity 584 00:51:45,640 --> 00:51:48,560 to investigate how the ocean here is changing. 585 00:51:49,840 --> 00:51:51,800 While we're observing the marine life down there, 586 00:51:51,880 --> 00:51:54,200 the subs are also recording what the environment is like, 587 00:51:54,280 --> 00:51:56,640 so we're getting measurements of temperature, of salinity. 588 00:51:56,720 --> 00:51:59,000 It's hopefully gonna enable us to understand the changes 589 00:51:59,080 --> 00:52:01,240 that are happening in this vital part of our planet. 590 00:52:04,280 --> 00:52:06,880 To get a fuller picture, John also lowers 591 00:52:06,960 --> 00:52:09,200 a deep sea temperature probe. 592 00:52:14,520 --> 00:52:18,200 His data is contributing to an international attempt 593 00:52:18,280 --> 00:52:21,920 to chart the rise in both sea and air temperatures. 594 00:52:25,080 --> 00:52:27,240 What shocks me about what all the data show 595 00:52:27,360 --> 00:52:29,880 is how fast things are changing here. 596 00:52:32,520 --> 00:52:35,320 We're headed into uncharted territory. 597 00:52:42,520 --> 00:52:44,560 To truly comprehend 598 00:52:44,640 --> 00:52:46,840 the effect of the temperature increases here, 599 00:52:46,920 --> 00:52:49,040 John takes to the skies. 600 00:52:50,200 --> 00:52:53,520 From here, he can record the number and size 601 00:52:53,600 --> 00:52:58,080 of the icebergs being produced as the ice shelves melt and break apart. 602 00:53:00,640 --> 00:53:04,080 The bergs we're seeing all around us give you some idea 603 00:53:04,160 --> 00:53:08,520 of how huge this process is that's taking place on the Antarctic. 604 00:53:09,840 --> 00:53:13,560 As the floating shelves break up, they allow water, 605 00:53:13,640 --> 00:53:17,120 which has been locked up on land as ice for thousands of years, 606 00:53:17,200 --> 00:53:19,000 to empty into the sea. 607 00:53:20,840 --> 00:53:24,080 And this is predicted to push up sea levels. 608 00:53:28,560 --> 00:53:31,760 If the ice shelves break up, then that opens the flood gates. 609 00:53:32,600 --> 00:53:34,720 Ice on land flows faster into the sea 610 00:53:34,800 --> 00:53:36,440 and that's what pushes up the sea levels. 611 00:53:38,360 --> 00:53:42,120 So, what's happening here right now affects all of us. 612 00:53:56,520 --> 00:54:00,520 Already, cities like Miami here are under threat. 613 00:54:01,400 --> 00:54:04,560 Scientists predict that by the end of the century, 614 00:54:04,640 --> 00:54:08,440 the sea levels could have risen by a metre or even two. 615 00:54:09,080 --> 00:54:13,640 Were that to happen, parts of this city would certainly be submerged. 616 00:54:18,360 --> 00:54:22,920 Around the world, hundreds of millions of people live near the coast, 617 00:54:23,000 --> 00:54:27,520 and as sea levels rise, their lives will be seriously affected. 618 00:54:40,760 --> 00:54:44,800 It's now clear that our actions are having a significant impact 619 00:54:44,880 --> 00:54:46,640 on the world's oceans. 620 00:54:51,320 --> 00:54:54,760 During the four years it took to make this series, 621 00:54:54,840 --> 00:54:57,920 we've witnessed many of these changes first-hand. 622 00:55:06,800 --> 00:55:09,880 But we've also worked alongside men and women 623 00:55:09,960 --> 00:55:13,720 dedicating their lives to safeguarding the ocean's future. 624 00:55:21,200 --> 00:55:24,440 The oceans provide us with oxygen, 625 00:55:24,520 --> 00:55:26,480 they regulate temperature, 626 00:55:26,560 --> 00:55:29,600 they provide us with food and energy supplies. 627 00:55:30,240 --> 00:55:35,080 And it's unthinkable to have a world without a healthy ocean. 628 00:55:38,960 --> 00:55:41,720 I still think we have the capability 629 00:55:41,800 --> 00:55:44,880 to change the manner in which we're wasting resources, 630 00:55:44,960 --> 00:55:46,920 in which we're poisoning our oceans, 631 00:55:47,040 --> 00:55:50,600 and we can look to a future with healthy oceans. 632 00:55:53,120 --> 00:55:57,600 When I look forward, I believe that if what we are doing 633 00:55:57,680 --> 00:56:00,120 can be duplicated just a little bit. 634 00:56:00,240 --> 00:56:03,080 These animals will have a chance of surviving. 635 00:56:04,640 --> 00:56:09,040 It comes down, I think, to us each taking responsibility 636 00:56:09,160 --> 00:56:11,760 for the personal choices that we make in our everyday lives. 637 00:56:11,840 --> 00:56:14,680 That's all any of us can be expected to do. 638 00:56:14,760 --> 00:56:17,320 And it is those everyday choices that add up. 639 00:56:32,760 --> 00:56:35,680 We are at a unique stage in our history. 640 00:56:36,600 --> 00:56:40,520 Never before have we had such an awareness 641 00:56:40,600 --> 00:56:42,560 of what we are doing to the planet. 642 00:56:43,600 --> 00:56:48,640 And never before have we had the power to do something about that. 643 00:56:50,720 --> 00:56:54,560 Surely, we have a responsibility to care for our blue planet. 644 00:56:55,680 --> 00:56:58,480 The future of humanity, 645 00:56:58,560 --> 00:57:01,800 and indeed all life on Earth, 646 00:57:01,880 --> 00:57:04,160 now depends on us. 54866

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