0:00:05 > 0:00:08The waters round the UK
0:00:08 > 0:00:13hide treasures and surprises we rarely get to see.
0:00:13 > 0:00:16Powered by Arctic currents to the north
0:00:16 > 0:00:19and the Gulf Stream from the south,
0:00:19 > 0:00:22our island occupies a unique position in the Atlantic Ocean.
0:00:25 > 0:00:27I'm explorer Paul Rose.
0:00:27 > 0:00:31I was base commander of the British Antarctic survey for ten years,
0:00:31 > 0:00:35and I've scuba-dived all around the world.
0:00:35 > 0:00:38Three, two, one, now. OK, that's them firing.
0:00:40 > 0:00:45But now I've come home to lead a team of specialists
0:00:45 > 0:00:48to uncover the secrets beneath our seas.
0:00:50 > 0:00:52Divers up.
0:00:52 > 0:00:55Joining me is marine biologist Tooni Mahto.
0:00:55 > 0:00:56Her underwater expertise
0:00:56 > 0:01:00will reveal the unexpected riches of British marine life.
0:01:00 > 0:01:05There's a vast amount of stinging power in those tentacles.
0:01:05 > 0:01:09Journalist and underwater archaeologist Frank Pope
0:01:09 > 0:01:12will examine the bigger picture of our relationship with the sea,
0:01:12 > 0:01:16and explore our maritime history.
0:01:16 > 0:01:19We are coming up the starboard side here.
0:01:19 > 0:01:21You get a sense of the scale of this ship.
0:01:24 > 0:01:29This series will take us on a journey right around our British seas,
0:01:29 > 0:01:33to uncover the most startling underwater wonders.
0:01:38 > 0:01:41This time we're exploring the waters around Scotland,
0:01:41 > 0:01:45home to some of the most rugged and isolated places in Britain.
0:01:45 > 0:01:49And that makes these seas perfect for some very special wildlife,
0:01:49 > 0:01:53but also for some very secret human activities.
0:01:56 > 0:01:59Beneath our waves is a world of secrets.
0:02:08 > 0:02:11The waters around our northern shores are wild and cold,
0:02:11 > 0:02:14and the weather can change in an instant.
0:02:14 > 0:02:19Our expedition begins on a glorious morning in the port of Dunbar.
0:02:21 > 0:02:25Scotland is renowned for its wildlife,
0:02:25 > 0:02:30perhaps none more so than its spectacular variety of seabirds.
0:02:30 > 0:02:33But over the past ten years,
0:02:33 > 0:02:37numbers of some species have declined dramatically.
0:02:37 > 0:02:40So, around the UK we have lost
0:02:40 > 0:02:4440% of our herring gulls, kittiwakes and fulmars in the last ten years.
0:02:44 > 0:02:48- That's a vast amount.- That's a huge number!- But there is one species
0:02:48 > 0:02:51that is doing rather better, and that's the northern gannet.
0:02:51 > 0:02:54They are doing exceptionally well in British waters.
0:02:54 > 0:02:58That's what I want to get to the bottom of, the fact that our gannets are doing well
0:02:58 > 0:03:01when the rest of world's seabirds are in decline.
0:03:03 > 0:03:06- Cheers, Frank.- Bye, guys. Have a good one!- See ya, Frank.
0:03:06 > 0:03:09To find out why the gannets are thriving,
0:03:09 > 0:03:15Tooni and I are heading out to one of the most amazing wonders of the natural world.
0:03:23 > 0:03:26Just two kilometres offshore,
0:03:26 > 0:03:30jutting out of the North Sea, is Bass Rock.
0:03:30 > 0:03:31This volcanic outcrop
0:03:31 > 0:03:34is the largest single-island colony of gannets in the UK,
0:03:34 > 0:03:36and a protected seabird sanctuary.
0:03:38 > 0:03:41This is such an unbelievable place.
0:03:41 > 0:03:44It is covered in bird poo.
0:03:44 > 0:03:46Urgh!
0:03:46 > 0:03:51So we're looking at over 100,000 gannets on Bass Rock at the moment,
0:03:51 > 0:03:52and come the end of breeding season,
0:03:52 > 0:03:56that will be about 150,000 after the chicks have hatched and matured.
0:03:56 > 0:04:02- Oh, there's a chick.- Where?- A tiny little chick's head poking out.
0:04:02 > 0:04:03Yeah, I can see them.
0:04:03 > 0:04:08To get a better understanding of the reasons behind the gannets' success,
0:04:08 > 0:04:11we've come to the island at nesting time.
0:04:11 > 0:04:15The rock is packed with breeding pairs and their chicks.
0:04:15 > 0:04:18While I'll be observing them underwater,
0:04:18 > 0:04:20Tooni will be investigating on land.
0:04:21 > 0:04:23I'll see you later.
0:04:28 > 0:04:33The reason for my hard hat is that these creatures are incredibly territorial,
0:04:33 > 0:04:36and they defend their space by dive-bombing
0:04:36 > 0:04:39and releasing some rather potent ammunition.
0:04:45 > 0:04:48As I walk up to the nesting sites,
0:04:48 > 0:04:52I'm getting dive-bombed by these fiercely protective animals.
0:04:53 > 0:04:55Bass Rock was once inhabited,
0:04:55 > 0:04:59but the last lighthouse keeper left in 1988,
0:04:59 > 0:05:03and now it's only the seabirds that remain.
0:05:03 > 0:05:05Oh, look, chicks!
0:05:08 > 0:05:14Gannets mate for life, returning to the same nest every year.
0:05:14 > 0:05:16Males and females look identical,
0:05:16 > 0:05:19and the only sure way to tell them apart is a DNA test.
0:05:19 > 0:05:21But when a male returns from fishing,
0:05:21 > 0:05:25he will often grab his partner by the scruff of the neck shake her.
0:05:28 > 0:05:33This is like the most visceral, complete, all-sensory experience you can have.
0:05:33 > 0:05:35It's noisy, it's smelly,
0:05:35 > 0:05:40you're right in the middle of a soap opera of life just happening all around you.
0:05:40 > 0:05:43It is absolutely magical!
0:05:43 > 0:05:46We're here to find out why the gannets are doing so well,
0:05:46 > 0:05:48so while Tooni's on the island,
0:05:48 > 0:05:50I am going to make a dive over here
0:05:50 > 0:05:54and see if I can find out how deep these gannets dive for their fish.
0:05:58 > 0:06:00Away you go, Paul!
0:06:00 > 0:06:03Well, I'm hiding under the boat,
0:06:03 > 0:06:06because if the gannets see my shape in the water they won't come in,
0:06:06 > 0:06:10they'll think I am a predator of some kind.
0:06:10 > 0:06:15To draw the feeding gannets closer to our boat, we throw in a few fish.
0:06:17 > 0:06:19Yay!
0:06:19 > 0:06:21Good one! Look at that!
0:06:24 > 0:06:27So, here you go, these birds, they are coming in.
0:06:27 > 0:06:31They get that momentum by diving from up to 30 metres high.
0:06:31 > 0:06:34So that means they hit the water at about 40 miles an hour,
0:06:34 > 0:06:38and if we did that we'd break our skulls,
0:06:38 > 0:06:43but they can get away with it because they have got super, super hard heads.
0:06:43 > 0:06:46Ah, that was a beautiful one.
0:06:46 > 0:06:47Gannets are built to dive.
0:06:49 > 0:06:51As well as their tough skulls,
0:06:51 > 0:06:54they have special air sacs in their chest
0:06:54 > 0:06:58which act as mini airbags to cushion the impact of hitting the water.
0:07:02 > 0:07:03Wow!
0:07:05 > 0:07:08I'm right here at six metres deep,
0:07:08 > 0:07:13but I can see the gannets going right down to about 20 metres.
0:07:13 > 0:07:16The gannets dive much deeper than other birds,
0:07:16 > 0:07:20so therefore they stand more chance of getting more food.
0:07:20 > 0:07:24It's pretty good watching these guys so close. You can really get a sense
0:07:24 > 0:07:30of how fast they hit the water and stun those fish!
0:07:30 > 0:07:33Back on Bass Rock, I've joined Dr Keith Hamer
0:07:33 > 0:07:35from the University of Leeds.
0:07:36 > 0:07:38The adult is looking up this way.
0:07:38 > 0:07:42You can't see the chick's head - it's preening itself, I think.
0:07:42 > 0:07:44To better understand the birds,
0:07:44 > 0:07:48Keith and his team are investigating the gannets' diet.
0:07:48 > 0:07:49Nicely done.
0:07:49 > 0:07:52But they're not always keen participants.
0:07:54 > 0:07:56Keith's research could help us understand
0:07:56 > 0:08:01why gannets are doing so well compared with other seabirds.
0:08:01 > 0:08:05When they open their beaks, it's then that you begin to appreciate
0:08:05 > 0:08:08quite how large and hard those beaks might be.
0:08:10 > 0:08:13That's it, good, so get your arms around the wings,
0:08:13 > 0:08:15make sure they are tucked in nicely.
0:08:15 > 0:08:18And then just keep a decent grip on the beak.
0:08:19 > 0:08:21That's an incredible strength.
0:08:21 > 0:08:23- Yes.- All right, I'm not going to hurt you.
0:08:23 > 0:08:25It's all in the name of science, I promise.
0:08:25 > 0:08:29Keith is retrieving tracking devices that he attached to the gannets
0:08:29 > 0:08:34to study how far these birds fly in search of food for their chicks.
0:08:34 > 0:08:36This is one of our GPS loggers.
0:08:38 > 0:08:42It talks to satellites, and it gives us a very precise location,
0:08:42 > 0:08:45so we can build up a track of where the bird's been.
0:08:45 > 0:08:49OK, so this is the device we got off a bird earlier,
0:08:49 > 0:08:54and what you can see here is the tracks of the trips that it made.
0:08:54 > 0:08:57The data shows that in the last week,
0:08:57 > 0:09:02this bird has flown over 750 kilometres hunting for food.
0:09:03 > 0:09:05Most British seabirds rarely travel
0:09:05 > 0:09:07more than 50 kilometres.
0:09:07 > 0:09:11So the gannets' extraordinary range must be a factor
0:09:11 > 0:09:13in their resilience.
0:09:13 > 0:09:17And Keith has found that, when food is scarce,
0:09:17 > 0:09:19gannets can fly as far as Norway,
0:09:19 > 0:09:25a four-day round trip of over 1,500 kilometres!
0:09:27 > 0:09:31The team have also been taking tissue samples from the gannets for chemical analysis,
0:09:31 > 0:09:35and they've turned up something very surprising.
0:09:35 > 0:09:37So, the feather and blood samples you take,
0:09:37 > 0:09:41what kind of information does that give you about the birds and what they are eating?
0:09:41 > 0:09:43The main things they feed on
0:09:43 > 0:09:46are either these small sand eels close to the surface,
0:09:46 > 0:09:50or they feed on predatory fish like mackerel and herring
0:09:50 > 0:09:52in the mid-water column.
0:09:52 > 0:09:57The rest of the diet is a mixture of species that live very close to the sea bed.
0:09:57 > 0:09:58These birds can dive about 20 metres,
0:09:58 > 0:10:02but things close to the sea bed are beyond that sort of range,
0:10:02 > 0:10:04or they are fish that are just too big
0:10:04 > 0:10:08for even a bird the size of a gannet to catch for themselves.
0:10:12 > 0:10:15What fascinates me is that from the research that Keith is doing here,
0:10:15 > 0:10:20and from what Paul saw earlier, some of the fish that the gannets are eating
0:10:20 > 0:10:26actually live far deeper than the limits of their diving abilities.
0:10:28 > 0:10:33So we know the gannets are eating fish that swim deeper than they can dive.
0:10:33 > 0:10:37We'll be investigating how they do this later on.
0:10:39 > 0:10:44Bass Rock is one of almost 800 islands in Scottish waters.
0:10:47 > 0:10:50I've travelled just over 300 kilometres
0:10:50 > 0:10:52to visit another rocky outcrop,
0:10:52 > 0:10:57located off the most north-westerly point of mainland Britain.
0:10:59 > 0:11:03This is one of the most sparsely populated areas in the country.
0:11:03 > 0:11:05And it's just as well.
0:11:07 > 0:11:09Here at the north-western tip of Britain, it's so remote
0:11:09 > 0:11:13that for the past 100 years, it has been used as a bombing range.
0:11:13 > 0:11:17And over there is Garvie Island, which is about the size
0:11:17 > 0:11:22of a medium-sized aircraft carrier, so it makes an ideal target.
0:11:22 > 0:11:27And this is the only place in Europe where you can drop live 1,000lb bombs.
0:11:37 > 0:11:40The sheer number of bombs dropped on Garvie Island every year
0:11:40 > 0:11:44mean that some of them inevitably fall into the sea,
0:11:44 > 0:11:48and some of those fail to explode, which makes this place
0:11:48 > 0:11:53the ideal training ground for one of the most dangerous jobs in the military -
0:11:53 > 0:11:55bomb disposal, underwater.
0:11:55 > 0:12:00Royal Navy divers come to these cold and turbulent waters each year
0:12:00 > 0:12:02to clear away unexploded ordnance,
0:12:02 > 0:12:05and it's a vital part of their training.
0:12:05 > 0:12:08I've joined Lieutenant Commander Jason White
0:12:08 > 0:12:12to find out how to defuse bombs under the waves.
0:12:12 > 0:12:16Underwater bomb disposal in some ways is probably easier than doing it on land.
0:12:16 > 0:12:20I was out in Iraq, we've got teams currently in Afghanistan as well.
0:12:20 > 0:12:23At least you've got no-one shooting at you underwater.
0:12:23 > 0:12:28It's all about getting the diving side so squared away that you're not really thinking about the diving.
0:12:28 > 0:12:32You get the diving to the point where that's just a way of getting to the job.
0:12:32 > 0:12:34So what kind of bombs are they?
0:12:34 > 0:12:41We've got mixed down there. We've got 1,000lb bombs, we've got 250kg bombs.
0:12:41 > 0:12:43Yeah, a 1,000lb bomb,
0:12:43 > 0:12:46if this thing went off underwater,
0:12:46 > 0:12:50while we were working on it, if we're up close on it, we're gone -
0:12:50 > 0:12:52- is that right?- Fish food.
0:12:53 > 0:12:58Bomb disposal is as complicated and dangerous underwater
0:12:58 > 0:13:00as it is on land, but at Garvie,
0:13:00 > 0:13:05the Navy divers also have to deal with cold waters and raging currents.
0:13:05 > 0:13:12On the Navy support ship, the team are preparing the explosives and detonators we'll be using later on.
0:13:12 > 0:13:18- That's really precise work, this isn't the sort of thing you want to screw up, is it?- No.- Yeah, exactly.
0:13:22 > 0:13:26I've worked with explosives in Antarctica, so I've got a licence to use them.
0:13:29 > 0:13:32But I've never done it underwater.
0:13:35 > 0:13:40The sea bed around Garvie Island is littered with unexploded bombs,
0:13:40 > 0:13:44but amongst the kelp, they can be very difficult to find.
0:13:46 > 0:13:49Navy divers take on many challenges,
0:13:49 > 0:13:53from underwater bomb disposal to rescuing submarines.
0:13:53 > 0:13:57And they get to use some seriously cool kit.
0:13:57 > 0:13:59As you can see,
0:13:59 > 0:14:02we're wearing very different diving equipment.
0:14:02 > 0:14:06You can see that Ginge is wearing this gear that makes no bubbles,
0:14:06 > 0:14:09it's called re-breather equipment, it's completely silent.
0:14:09 > 0:14:13There's a reason for that, and one of them is that some live bombs
0:14:13 > 0:14:17can be activated by noise, they're acoustically sensitive.
0:14:17 > 0:14:21These bombs here are not acoustically activated,
0:14:21 > 0:14:23which means I can wear the lighter,
0:14:23 > 0:14:27easier-to-use open circuit, so I can make some bubbles quite safely.
0:14:30 > 0:14:34Ginge's rebreather removes the carbon dioxide and recycles oxygen,
0:14:34 > 0:14:39which means he can stay down for longer looking for bombs.
0:14:43 > 0:14:46Oh, yeah, look.
0:14:46 > 0:14:50Found a bomb!
0:14:50 > 0:14:54You see, you can swim right past them, and I just did -
0:14:54 > 0:14:56I thought this was a rock.
0:14:56 > 0:15:00It's a whopper. What do you think, mate?
0:15:01 > 0:15:04Oh, keep away from it? OK.
0:15:04 > 0:15:07Ginge has given me the sign, he's not sure about this one.
0:15:07 > 0:15:12He's declared it a live so he's given me the hands-off signal - if that thing went off,
0:15:12 > 0:15:14we'd be in big trouble.
0:15:16 > 0:15:20The bomb is live, but once he's examined it and determined the risk,
0:15:20 > 0:15:24Ginge is happy for me to return and help him tie a buoy to it.
0:15:26 > 0:15:29We're going to mark this now with this rope, that way we will know
0:15:29 > 0:15:33exactly that when we come back down this line, that we'll be coming exactly to this bomb.
0:15:38 > 0:15:40Good one. Thanks, Ginge.
0:15:42 > 0:15:45With the bomb's position marked, we return to the surface
0:15:45 > 0:15:48to collect the plastic explosive we prepared earlier.
0:15:48 > 0:15:52I'll tell you what, that was great!
0:15:52 > 0:15:57You want to get yourself aside a 1,000lb bomb to get the blooming juices flowing!
0:15:57 > 0:16:01A bit sobering as well. You can't mess around with this stuff,
0:16:01 > 0:16:03absolutely can't mess around with it.
0:16:07 > 0:16:08Diving back down the line,
0:16:08 > 0:16:13we've now got to secure the plastic explosive to the bomb.
0:16:15 > 0:16:19Not an easy task when it's embedded in the sea floor.
0:16:19 > 0:16:20Got it.
0:16:23 > 0:16:26I can't get to that end.
0:16:26 > 0:16:32So we're going to get a sandbag sent down from the surface to plant on top of here.
0:16:41 > 0:16:45You see, it's hard work, because not only are we swimming around
0:16:45 > 0:16:49with live explosives, we're also dealing with this really strong current, look.
0:16:49 > 0:16:53The current's going that way, it's like a steam train.
0:16:54 > 0:16:56Here's the sandbag.
0:16:56 > 0:16:59Brilliant.
0:16:59 > 0:17:00It's going to make life easier.
0:17:00 > 0:17:03Ha-ha! Thanks, mate! That's it.
0:17:06 > 0:17:08It's ready to go.
0:17:08 > 0:17:10Time for us to swim away, I think!
0:17:10 > 0:17:16Ha-ha! It's a great place to be - but not for much longer.
0:17:17 > 0:17:19Just line it up there, Paul...
0:17:19 > 0:17:24Safely back on the surface, we need to ignite a fuse that will slowly
0:17:24 > 0:17:28burn underwater, all the way to the explosive we attached to the bomb.
0:17:28 > 0:17:30OK. Three, two, one, now.
0:17:30 > 0:17:33OK, that's them firing.
0:17:33 > 0:17:35- Now you unscrew them.- Yep.
0:17:35 > 0:17:38That's burning now. That's alive now.
0:17:38 > 0:17:41This is the point of no return.
0:17:41 > 0:17:44It's time we left!
0:17:44 > 0:17:46Fuse is burning.
0:17:46 > 0:17:48- How long have we got?- Five minutes.
0:17:48 > 0:17:54- We've got five minutes, OK. How far away do we have to be?!- Er, well, as far as possible, really.
0:18:11 > 0:18:16Yes! See? If we're going to use that as the bull's-eye for the...
0:18:16 > 0:18:23most bombed place in Europe, then we have responsibility for cleaning up the ones that didn't explode.
0:18:23 > 0:18:26These are the ones to do it. Pretty exciting stuff. Thanks very much.
0:18:26 > 0:18:28- OK, no problem.- I'm all fired up!
0:18:36 > 0:18:41Despite periods of intense bombardment several times a year, military activities and wildlife
0:18:41 > 0:18:46have co-existed in the Cape Wrath area for over 70 years -
0:18:46 > 0:18:49largely because people are kept away.
0:18:49 > 0:18:54But you don't need to go somewhere this remote to see some very special marine creatures.
0:18:56 > 0:19:00The wild coast of Scotland is home to some of Britain's biggest marine mammals.
0:19:00 > 0:19:05Orca, minke and pilot whales can all be spotted here.
0:19:05 > 0:19:09It's also the home to many people's favourite sea creature, the dolphin.
0:19:13 > 0:19:17Britain's largest resident population
0:19:17 > 0:19:22of 130 bottlenose dolphins live in the Moray Firth,
0:19:22 > 0:19:24just north of Inverness.
0:19:24 > 0:19:28Many will stay here all year, whilst others will travel down
0:19:28 > 0:19:30as far south as the Firth of Forth,
0:19:30 > 0:19:34tracking schools of salmon and mackerel along the coastline.
0:19:35 > 0:19:39Their acrobatic displays have made these north-eastern waters
0:19:39 > 0:19:41a magnet for dolphin watching,
0:19:41 > 0:19:44contributing over £4 million a year to the local economy.
0:19:46 > 0:19:51The ones here are a lot bigger and fatter than the bottlenose dolphins
0:19:51 > 0:19:55in, say, the Caribbean, Indian or Pacific oceans because they need this thick layer
0:19:55 > 0:19:59of blubber to keep them warm in the cold waters of the North Sea.
0:19:59 > 0:20:03How do dolphins keep their family pods together?
0:20:03 > 0:20:09Intriguingly, it might be by using an equivalent to human names.
0:20:09 > 0:20:13As human beings, we know if we're being called,
0:20:13 > 0:20:17irrespective of who is calling us, because we recognise our own name.
0:20:17 > 0:20:22Between the ages of one and two years, bottlenose dolphins
0:20:22 > 0:20:27create their own unique sound, known as a signature whistle.
0:20:27 > 0:20:30But is it a name in the same way we understand one?
0:20:36 > 0:20:41Stephanie King, a zoologist from the Sea Mammal Research Unit, is researching this.
0:20:41 > 0:20:46They have been studying the calls of dolphins in this area since 2003.
0:20:48 > 0:20:51So what's the aim of this research you're doing in the Moray Firth?
0:20:51 > 0:20:56Well, we know dolphins use signature whistles to communicate with one another to broadcast their identity,
0:20:56 > 0:21:00and we know that they sometimes copy each other.
0:21:00 > 0:21:02So they'll copy one another's signature whistle - and we really want to know why,
0:21:02 > 0:21:06what's the function of them copying another dolphin's signature whistle?
0:21:06 > 0:21:09It's believed dolphins may copy each other's signature whistles
0:21:09 > 0:21:12in order to address one another.
0:21:12 > 0:21:16To find out, we'd need to show that a wild dolphin can recognise
0:21:16 > 0:21:19its "name" and respond to it.
0:21:19 > 0:21:23And if they can, they would be the only animal apart from human beings
0:21:23 > 0:21:26that are capable of doing that.
0:21:29 > 0:21:31Working with wild dolphins is challenging.
0:21:31 > 0:21:33They're constantly on the move,
0:21:33 > 0:21:37but it's essential that Stephanie can identify the animals she's working with.
0:21:39 > 0:21:43So we want to take photos of the dorsal fins of the animals -
0:21:43 > 0:21:45and this is how we can track individuals.
0:21:45 > 0:21:50They have certain scarrings and little tears, which we call nicks, along the fin.
0:21:50 > 0:21:55- You get very familiar with what animals are out here?- Yeah, you do.
0:21:55 > 0:21:57There they are.
0:22:07 > 0:22:09Literally all around, aren't they?
0:22:09 > 0:22:13It's hard to differentiate between different groups.
0:22:15 > 0:22:18So try to keep those animals in sight, let's not lose them.
0:22:18 > 0:22:20Dolphins don't generally make their signature whistles
0:22:20 > 0:22:26when they're travelling, so we have to stay with the group until they begin socialising.
0:22:26 > 0:22:32To find out if they're whistling, we'll listen using a special underwater microphone
0:22:32 > 0:22:35- called a hydrophone.- Now we're going to put the back hydrophones in.
0:22:35 > 0:22:41- OK.- So if you grab the one on the port side, I'll go to the starboard.
0:22:41 > 0:22:45Any sounds that the hydrophone picks up will be recorded to a laptop.
0:22:54 > 0:22:58Lots of clicking. Quick, quick, quick, they're whistling!
0:23:00 > 0:23:01You picked them up on the hydrophone?
0:23:01 > 0:23:04- You heard them whistling almost instantly? - They were whistling a lot.
0:23:04 > 0:23:09It's quite exciting when you pick up some recordings, because sometimes they can be quiet for hours.
0:23:11 > 0:23:12- Do you want to hear?- I'd love to.
0:23:14 > 0:23:17So this is a dolphin signature whistle.
0:23:17 > 0:23:20HIGH-PITCHED WHISTLING
0:23:23 > 0:23:27That's a really lovely sound!
0:23:27 > 0:23:31This is the sound of one dolphin making his own signature whistle.
0:23:31 > 0:23:36But we need to play it back to him as if it came from another dolphin.
0:23:36 > 0:23:39Our first step is to create a computer-generated version.
0:23:39 > 0:23:43So it's exactly the same whistle but we take away all the voice features.
0:23:43 > 0:23:47So it's like another animal calling the dolphin.
0:23:47 > 0:23:50And then we play it back through the loudspeaker.
0:23:50 > 0:23:55We need to be able to see how our dolphin pod react when they hear the modified whistle.
0:23:55 > 0:23:59But we can only do this when they're near the surface.
0:24:05 > 0:24:07OK, great. That's our group!
0:24:07 > 0:24:11- Nine o'clock, 300-400 metres. - Straight into the water.
0:24:14 > 0:24:16Speaker in...
0:24:16 > 0:24:19Animals still at 12 o'clock now.
0:24:19 > 0:24:23- Playback.- Stephanie only plays the signature whistle twice
0:24:23 > 0:24:26and observes their response.
0:24:26 > 0:24:28- Are they still up?- Yep.
0:24:28 > 0:24:32OK, half past two, three o'clock animal, this one's a bit closer now than the others.
0:24:32 > 0:24:34The others are 120 metres,
0:24:34 > 0:24:37that animal's about 80-90 metres.
0:24:39 > 0:24:40Jumping.
0:24:43 > 0:24:45Interaction. Jumping backwards...
0:24:45 > 0:24:50At the same time, the underwater microphone is recording any sounds the dolphins are making.
0:24:53 > 0:24:57The results of the team's research have been intriguing.
0:24:57 > 0:25:02The dolphins appear to be recognising their own whistle and calling back.
0:25:02 > 0:25:05Right, so this is what we recorded earlier.
0:25:05 > 0:25:08So here we have the playback, it's a very clear signal.
0:25:08 > 0:25:11And then we see the fainter ones are the responses of the animals.
0:25:11 > 0:25:14And you can see here we have the playback sound
0:25:14 > 0:25:15and then the animals responding -
0:25:15 > 0:25:18and there's a copy of that whistle.
0:25:18 > 0:25:21- It's very, very clear.- Mmm, very clear, and not just that but
0:25:21 > 0:25:26the other animals are responding, they also call their whistle.
0:25:26 > 0:25:32As well as whistling, the dolphins in the pod have swum towards the underwater speaker,
0:25:32 > 0:25:35which suggests they do recognise the call or "name"
0:25:35 > 0:25:38as being that of one of their group.
0:25:38 > 0:25:42So is it like if we were in a darkened room, and in order
0:25:42 > 0:25:46to assess who was there, we'd all call out our own names,
0:25:46 > 0:25:49so everybody would know where everybody else was?
0:25:49 > 0:25:53Yeah, exactly, instead of calling out names of other people, you would call your own name.
0:25:53 > 0:25:56I'd be calling, "Stephanie, Stephanie", you'd be saying, "Tooni, Tooni".
0:25:56 > 0:25:59And that way we'd know who's there, we'd come back together and join up again.
0:25:59 > 0:26:01It makes more sense in an underwater environment,
0:26:01 > 0:26:04if you're not sure who's there, to broadcast your own identity,
0:26:04 > 0:26:08to bring the group back together, rather than calling other animals' signatures at random.
0:26:10 > 0:26:13As well as calling their own name, the dolphins will also copy
0:26:13 > 0:26:15the signature whistle of others in their group.
0:26:15 > 0:26:19Stephanie's work has begun to show that when a dolphin hears
0:26:19 > 0:26:24its own signature whistle, it responds and calls back.
0:26:24 > 0:26:29When Stephanie plays them a whistle from a dolphin they don't know, they don't react.
0:26:29 > 0:26:33With the controls, the whistles aren't that different, but they don't respond.
0:26:33 > 0:26:38- These dolphins just recognise the whistles of the animals they associate with.- That's fantastic!
0:26:40 > 0:26:44So each bottlenose dolphin has a name that it develops itself,
0:26:44 > 0:26:46and that the others in its pod recognise.
0:26:46 > 0:26:52And dolphins seem to be copying each other's names in order to call one another -
0:26:52 > 0:26:55which means dolphins are the only animal, other than us,
0:26:55 > 0:26:58that have been shown to use names in this way.
0:27:00 > 0:27:03Stephanie's research is just the tip of the iceberg.
0:27:03 > 0:27:06It could not only help us understand the evolution of language,
0:27:06 > 0:27:11but could also give us an insight into the complex existence
0:27:11 > 0:27:13of a highly intelligent mammal.
0:27:18 > 0:27:21The North Sea may hold many more secrets.
0:27:21 > 0:27:25From better understanding the creatures that live there,
0:27:25 > 0:27:28to offering resources that could unlock new ways of treating disease.
0:27:28 > 0:27:33One of the myths of undersea Britain is that it's dull, lifeless
0:27:33 > 0:27:36and there's not very much to look at.
0:27:36 > 0:27:39Tooni and I have come to St Abbs.
0:27:39 > 0:27:41The area is a marine reserve.
0:27:41 > 0:27:45It benefits from a flow of Atlantic water entering the North Sea around
0:27:45 > 0:27:51Scotland's northern tip but also from a cooler Arctic influence.
0:27:51 > 0:27:53Because of the strength of the water rushing down,
0:27:53 > 0:27:56there's a huge amount of nutrients and life going on down there,
0:27:56 > 0:27:59- so it should be a really exciting dive.- Oh, yeah, I'm in.
0:27:59 > 0:28:06I'm in! We're here to reveal that our marine life is not only more colourful than you'd imagine
0:28:06 > 0:28:09but could also help in the fight against cancer.
0:28:19 > 0:28:21Wow!
0:28:21 > 0:28:27St Abbs is such a special dive site because there's such a diversity of life here.
0:28:27 > 0:28:30Not only are there the kelp forests beneath us,
0:28:30 > 0:28:35but there's also these giant expanses of rock face
0:28:35 > 0:28:39that provide a hard substrate for all of this marine life to colonise.
0:28:43 > 0:28:45Water filters out sunlight.
0:28:45 > 0:28:49The deeper you dive, the more colours disappear.
0:28:49 > 0:28:52But with our torches, we can put the daylight back
0:28:52 > 0:28:57and reveal the magnificent creatures as they really are.
0:28:57 > 0:29:01This wall is pretty fantastic, Tooni, look at it.
0:29:01 > 0:29:05And there's no shortage of beautiful natural colour, is there?
0:29:05 > 0:29:08Yeah. Actually, whereas things look quite dull, once you shine
0:29:08 > 0:29:13- your torch on them, it really picks out the reds. - Even these urchins are beautiful.
0:29:13 > 0:29:16You take your light away and they're just black and white.
0:29:16 > 0:29:19You put your light back, and look at the colours!
0:29:27 > 0:29:30Those wrasse are very inquisitive. That's a classic case.
0:29:30 > 0:29:34He looks really brown and murky but when you shine a light on him,
0:29:34 > 0:29:36you can pick out his red colouring.
0:29:41 > 0:29:43Not every creature wants to be seen.
0:29:43 > 0:29:47You wouldn't even notice some marine life unless it moved -
0:29:47 > 0:29:49like this lemon sole.
0:29:49 > 0:29:51Ah! Look at him! Ha-ha!
0:29:55 > 0:29:58He's using his colour to camouflage himself, isn't he?
0:29:58 > 0:30:00Absolutely.
0:30:00 > 0:30:02Animals use colour underwater
0:30:02 > 0:30:05in almost exactly the same way as they do up on land.
0:30:05 > 0:30:09So there's camouflage to blend into the surroundings,
0:30:09 > 0:30:12to signal to a mate, or to advertise
0:30:12 > 0:30:16that they're maybe poisonous, they use these bright reds and yellows.
0:30:19 > 0:30:24Well, if you had to pick one single dive in British waters
0:30:24 > 0:30:28to dispel the myth about what's really under the sea -
0:30:28 > 0:30:33is it dull, lifeless, is it not very interesting, and not very colourful?
0:30:33 > 0:30:35Then this must be the dive.
0:30:39 > 0:30:42But to see how colour may offer help in the fight against cancer,
0:30:42 > 0:30:45we have to come back at night -
0:30:45 > 0:30:48to see something that's normally beyond human vision.
0:30:48 > 0:30:53Scientists think that some marine animals can see colours far beyond those that we can.
0:30:53 > 0:30:56So we've come back to our dive site at night
0:30:56 > 0:31:01with some special equipment in order to reveal some of the secret colours
0:31:01 > 0:31:03of the underwater world.
0:31:13 > 0:31:16OK, well, let's go see what go and see what we can find, I guess.
0:31:25 > 0:31:27Wow! All the anemones are out feeding.
0:31:27 > 0:31:30So many crabs out!
0:31:30 > 0:31:34Many marine creatures can see beyond our visual range -
0:31:34 > 0:31:36some even fluoresce.
0:31:36 > 0:31:41For us to see this, we're going to need blue lights,
0:31:41 > 0:31:43and special orange specs.
0:31:43 > 0:31:47Right, so this is the barrier filter going on,
0:31:47 > 0:31:51which is the slightly forensic-looking yellow mask.
0:31:53 > 0:31:58This is the blue light which we'll shine onto the marine animals
0:31:58 > 0:32:02to actually see if they're emitting any of the fluorescence.
0:32:08 > 0:32:11Ah, Tooni!
0:32:11 > 0:32:13Tooni!
0:32:15 > 0:32:17Oh, wow!
0:32:17 > 0:32:20God, it completely springs out at you!
0:32:22 > 0:32:27The combination of blue light and orange filters allow us to see
0:32:27 > 0:32:28this extraordinary phenomenon -
0:32:28 > 0:32:32something that's never been filmed before in British waters.
0:32:34 > 0:32:39Now these anemones, it's thought that they actually fluoresce
0:32:39 > 0:32:43because their main prey item is cocapods,
0:32:43 > 0:32:45which live in the plankton.
0:32:45 > 0:32:48And cocapods fluoresce to attract a mate,
0:32:48 > 0:32:52so it could be that the anemones have evolved
0:32:52 > 0:32:57this fluorescent protein to get their prey to come to them.
0:32:58 > 0:33:00Oh, wow!
0:33:00 > 0:33:03Just look at that!
0:33:03 > 0:33:05That is some fantastic colouring.
0:33:05 > 0:33:07It really jumps out at you!
0:33:07 > 0:33:11That is just absolutely beautiful, isn't it, Tooni? Look at it!
0:33:11 > 0:33:13That's fantastic!
0:33:17 > 0:33:21They're called lightbulb sea squirts.
0:33:21 > 0:33:24And the way in which they feed, and why they're called squirts,
0:33:24 > 0:33:29is because they pump water in one way, extract their planktonic food,
0:33:29 > 0:33:34and then pump the exhaust fumes, as it were, out the other way.
0:33:36 > 0:33:38Everything's fluorescing! Ha!
0:33:40 > 0:33:42Scientists have identified the gene
0:33:42 > 0:33:46that produces the fluorescent protein in marine lifeforms.
0:33:46 > 0:33:49And intriguingly, this discovery has been used
0:33:49 > 0:33:52to help study cancerous cells.
0:33:52 > 0:33:57Basically some cellular processes are really hard to see
0:33:57 > 0:34:01because they're so microscopic. These fluorescent proteins
0:34:01 > 0:34:04are actually used to mark this, so it's a lot easier to see.
0:34:06 > 0:34:10The fluorescence acts like a marker in the cancer cells,
0:34:10 > 0:34:13allowing them to be studied and precisely tracked.
0:34:14 > 0:34:19So there's a lot of research at the moment in deep-sea biology
0:34:19 > 0:34:22to try and find more marine organisms that fluoresce.
0:34:22 > 0:34:24That's fantastic work.
0:34:24 > 0:34:27What a brilliant part of the ocean eco-system.
0:34:27 > 0:34:30And it's the potential for scientific advances such as these
0:34:30 > 0:34:33which makes it so important for us
0:34:33 > 0:34:37to respect the seas and marine life that surround our own island.
0:34:39 > 0:34:44- Good one?- Yeah, that was great. What a way to end the dive, hey?
0:34:44 > 0:34:48It's pretty special going down on a night dive and coming back at dawn.
0:34:48 > 0:34:48Look at that.
0:34:48 > 0:34:53People always say there is so much to discover in terms of human health in the rainforest,
0:34:53 > 0:34:57but it's exactly the same with everything under the ocean as well.
0:34:57 > 0:35:00Down here on the east coast of Scotland there're things
0:35:00 > 0:35:03you can track cancer cells with. I think that's amazing.
0:35:15 > 0:35:19Here at Bass Rock, Tooni and I have been investigating how gannets can be doing so well
0:35:19 > 0:35:21when other seabirds are in decline.
0:35:21 > 0:35:24And Frank's out there on the ocean
0:35:24 > 0:35:27looking at how fishing is affecting seabird populations.
0:35:36 > 0:35:40We're on the Launch Out, which is a trawler that's fishing for prawns
0:35:40 > 0:35:42off the east coast of Scotland.
0:35:42 > 0:35:47Prawns, as Scottish fishermen commonly refer to langoustine, live in burrows on the sea bed.
0:35:49 > 0:35:52Trawlers catch them by dragging huge nets along the bottom.
0:35:56 > 0:36:00The skipper on this trawler is Jim Wood.
0:36:00 > 0:36:01How long have you been doing this?
0:36:01 > 0:36:03I've been in the wheelhouse for 32 years.
0:36:03 > 0:36:05In the wheelhouse for 32 years?
0:36:05 > 0:36:08My father got this boat built in '67
0:36:08 > 0:36:11and my grandfather, he was a fisherman before that,
0:36:11 > 0:36:13and my great-grandfather before that.
0:36:13 > 0:36:18I don't know any further back than that. Four generations anyway.
0:36:18 > 0:36:22- Pretty safe to say they were fishermen too.- Probably. Aye.
0:36:22 > 0:36:25- And always fishing for prawns or what?- No.
0:36:25 > 0:36:30For the first 20 years, it was mainly fish. White fish, mainly. Haddock.
0:36:30 > 0:36:33- Plaice. Sole.- And then what happened?
0:36:33 > 0:36:35The fish took off.
0:36:35 > 0:36:42- So we've landed prawns for the last 15 years.- So the fish moved out?
0:36:42 > 0:36:44The fish have moved away from this area. Yeah.
0:36:44 > 0:36:48Whether the fish have moved due to warming waters pushing cold water species away,
0:36:48 > 0:36:53or simply because we have fished out the area, is still open for debate.
0:36:53 > 0:36:57But the change in the amount, and types of fish available,
0:36:57 > 0:37:01has dramatically affected some seabirds.
0:37:01 > 0:37:04And commercial fishing techniques have also had a direct impact.
0:37:06 > 0:37:08In the North Sea and the Baltic,
0:37:08 > 0:37:13there are some 90,000 birds that get killed every year in fishing tackle.
0:37:13 > 0:37:18That's quite a big problem.
0:37:18 > 0:37:21But somehow, gannets are thriving against the odds
0:37:21 > 0:37:24when other seabird populations are in decline.
0:37:24 > 0:37:28And I think I know why.
0:37:28 > 0:37:34Did we catch anything?
0:37:34 > 0:37:35Wow!
0:37:35 > 0:37:41So look at that. There's a fair amount of prawn in here.
0:37:41 > 0:37:44These are what we're after.
0:37:44 > 0:37:48Look what else has come up as well.
0:37:48 > 0:37:51All the crabs. That's a dab.
0:37:51 > 0:37:56Look at him, he's a murky-looking fellow from the deep.
0:37:56 > 0:37:59Anything else, James?
0:37:59 > 0:38:01A huge proportion of prawns but there are other things in here
0:38:01 > 0:38:04and this is what you call the by-catch.
0:38:04 > 0:38:09By-catch is the name given to any marine life unintentionally caught.
0:38:12 > 0:38:15Every year in the North Sea,
0:38:15 > 0:38:19fishermen net around 900,000 tonnes of by-catch.
0:38:19 > 0:38:24That's the equivalent of about 120,000 Route Master London buses.
0:38:27 > 0:38:30By-catch is strictly regulated by the European Union.
0:38:30 > 0:38:34Any animal deemed too small or outside your quota,
0:38:34 > 0:38:35has got to be discarded.
0:38:35 > 0:38:40But most of it will already be dead by the time it's thrown back.
0:38:40 > 0:38:45This terrible waste provides a feast for the waiting gannets.
0:38:45 > 0:38:49These offshore trawlers offer a fast food supply.
0:38:49 > 0:38:54But of the British seabirds, it's only the gannets that have the incredible range that allows them
0:38:54 > 0:38:58to fly the hundreds of kilometres to where these boats often fish.
0:39:01 > 0:39:06So the gannets are able to eat fish that live deeper than they are able to dive
0:39:06 > 0:39:09because the fishermen are catching it for them,
0:39:09 > 0:39:14and they are throwing their unwanted catch over the side.
0:39:14 > 0:39:15The gannets are greedy opportunists,
0:39:15 > 0:39:21a bit like urban foxes, and they've adapted to eat pretty much anything
0:39:21 > 0:39:23they can get their beaks on.
0:39:26 > 0:39:29So, the gannets' varied diet has certainly helped them
0:39:29 > 0:39:31buck the trend of declining seabird populations.
0:39:31 > 0:39:36In fact, they've been so successful here on Bass Rock that it has reached capacity.
0:39:36 > 0:39:40There is simply no more room for any more birds.
0:39:45 > 0:39:48While this rugged and desolate coastline may offer a safe haven
0:39:48 > 0:39:52for seabirds, it's been the undoing of a great many ships.
0:39:56 > 0:40:02We've come to the Sound of Mull, off the west coast of Scotland.
0:40:02 > 0:40:06For centuries, these waters have provided a cut-through for shipping.
0:40:06 > 0:40:12But bad weather, rocky outcrops and warfare have lead to numerous wrecks
0:40:12 > 0:40:16lying at the bottom of her clear waters.
0:40:16 > 0:40:19Frank and I have both dived a particular wreck here before,
0:40:19 > 0:40:22but we've returned to see how much has changed,
0:40:22 > 0:40:25and how we might protect our maritime history.
0:40:28 > 0:40:31There are over 25,000 shipwrecks recorded in British waters
0:40:31 > 0:40:33but they are slowly being lost to us.
0:40:33 > 0:40:37Not just by forces of nature, but also because of human activity.
0:40:39 > 0:40:42This is the Breda, a Dutch cargo ship.
0:40:42 > 0:40:48During the Second World War, she was carrying supplies to British troops,
0:40:48 > 0:40:51everything from shaving kits to bi-planes.
0:40:51 > 0:40:54But on 23rd December 1940, enroute to Mombasa,
0:40:54 > 0:40:57she was attacked by a German bomber.
0:40:59 > 0:41:01I was first here in '82,
0:41:01 > 0:41:05and I remember coming back from the US.
0:41:05 > 0:41:10I was nine years old.
0:41:10 > 0:41:12- Oh, I love it. Were you 9? - So what did you see in '82?
0:41:12 > 0:41:16Well, I remember the decks being strewn with stuff.
0:41:16 > 0:41:19You could go down, find this, find that,
0:41:19 > 0:41:22find great big brass things, and you know just get amongst it
0:41:22 > 0:41:26and get stuff home and put it on your mantelpiece or something.
0:41:26 > 0:41:29Increasingly among the dive clubs, people say don't take anything,
0:41:29 > 0:41:31because you are spoiling it for everyone else,
0:41:31 > 0:41:36you're spoiling it for the historians and for the other divers
0:41:36 > 0:41:39but was there any kind of that sense when you dived it?
0:41:39 > 0:41:43No. No. There wasn't. Very much the opposite.
0:41:43 > 0:41:46There was a keenness, amongst everybody,
0:41:46 > 0:41:50to bring up to the surface as much as you possibly could.
0:41:50 > 0:41:51I've got a treat for you.
0:41:51 > 0:41:54Here's what I looked like when I dived this thing in '82, are you ready?
0:41:54 > 0:42:00- Oh, my God... Let's have a look! - You need to brace yourself.
0:42:00 > 0:42:03That's what I looked like.
0:42:03 > 0:42:05It's Burt Reynolds!
0:42:09 > 0:42:14One of the magical things about diving a shipwreck is that you get a sense of stepping back in time.
0:42:18 > 0:42:21But of course wreck diving can be dangerous. Our dive supervisor,
0:42:21 > 0:42:25Richard Bull, is laying out strict ground rules.
0:42:25 > 0:42:30This is a union dive. What that means is one out, all out.
0:42:31 > 0:42:33If one person has to bail, we all come up.
0:42:34 > 0:42:37Since I last dived the Breda in 1995,
0:42:37 > 0:42:41three people have lost their lives exploring this wreck.
0:42:41 > 0:42:45Two people with collapsing material, right?
0:42:45 > 0:42:48Well, let's not get into those situations.
0:42:48 > 0:42:51Just because it is underwater doesn't mean those large lumps
0:42:51 > 0:42:54are not affected by gravity.
0:42:54 > 0:42:57They come down, all right? It would spoil the whole day if we...
0:42:57 > 0:43:00- Lost somebody.- Had to deal with something very unpleasant like that.
0:43:00 > 0:43:03- Got that one?- Deal. - No heroes, right. Deal.
0:43:08 > 0:43:10Down we go, mate. Here we go.
0:43:10 > 0:43:15We're here to see how much has changed on this Second World War cargo ship
0:43:15 > 0:43:18since Paul first dived her nearly 30 years ago.
0:43:18 > 0:43:22I love this moment, when the wreck first appears out of the gloom.
0:43:22 > 0:43:26It's a lovely feeling, isn't it? We're back on the Breda!
0:43:30 > 0:43:35- Wow.- So we are coming up the starboard side, here.
0:43:35 > 0:43:39You get a sense of the scale of this ship.
0:43:41 > 0:43:45Ah, OK, look down, look down here.
0:43:45 > 0:43:49This is probably the main hold here.
0:43:49 > 0:43:52This must be hold number four, Frank.
0:43:56 > 0:43:58Probably. This hold is about three storeys high.
0:43:58 > 0:44:01It would once have been full of cargo.
0:44:03 > 0:44:07Whilst a lot of the cargo was salvaged at the time
0:44:07 > 0:44:10and some of the artefacts will have naturally rotted away,
0:44:10 > 0:44:14what's striking here is just how little remains.
0:44:14 > 0:44:18This site used to be full of...
0:44:18 > 0:44:22all the paraphernalia of living in the 1940s.
0:44:22 > 0:44:25Holy smokes, it does look a lot different!
0:44:25 > 0:44:31It's a very different shipwreck to the one I saw in 1982.
0:44:31 > 0:44:35There was just a lot more stuff around.
0:44:35 > 0:44:40A lot more boxes and discarded tools and equipment.
0:44:40 > 0:44:43But now look, it's all gone.
0:44:43 > 0:44:47It's been picked clean.
0:44:47 > 0:44:49It's been picked clean by the hundreds and hundreds,
0:44:49 > 0:44:52probably thousands of divers that have been here.
0:44:56 > 0:45:02Since the early days of diving, we've had to report all finds to the maritime authorities.
0:45:02 > 0:45:04But while it was once common to pick up souvenirs,
0:45:04 > 0:45:09we've now got a much greater appreciation for wrecks
0:45:09 > 0:45:12as historical sites that should be kept intact.
0:45:18 > 0:45:22What's so important here, Paul, is to remember
0:45:22 > 0:45:27this is a museum, really. If each one of us takes one souvenir,
0:45:27 > 0:45:34pretty soon that's it, and there won't be anything left to give the sense of the people
0:45:34 > 0:45:36who sailed on board her.
0:45:38 > 0:45:41Fortunately there are still a few large pieces left on board
0:45:41 > 0:45:45that remind us this was a cargo ship on her way to the frontline.
0:45:46 > 0:45:49Tyres, wheels. Oh, yeah,
0:45:49 > 0:45:54this is a big four-wheel-drive truck.
0:45:56 > 0:45:58Look, you can see the differential here.
0:45:58 > 0:46:00Ha-ha, yeah.
0:46:00 > 0:46:06Well, that's it, I'd love to spend a lot longer on this lovely shipwreck,
0:46:06 > 0:46:10but sadly, it's time for us to go.
0:46:13 > 0:46:16Five divers on the surface, aren't we happy, people!
0:46:16 > 0:46:18Five went down, five came back.
0:46:18 > 0:46:21It was a good day.
0:46:21 > 0:46:26It would be hugely expensive to raise and protect a wreck like the Breda,
0:46:26 > 0:46:31but new technology may allow us to preserve her in another way.
0:46:31 > 0:46:35In fact to experience her you won't even need to be a diver...
0:46:37 > 0:46:40This is really cutting edge, now.
0:46:40 > 0:46:43This has been surveyed in a way that not many wrecks have been.
0:46:43 > 0:46:47To capture the wreck before she decays any further,
0:46:47 > 0:46:51the Breda has been surveyed using technology developed by the oil industry.
0:46:51 > 0:46:56A sonar scan has created a high resolution, three-dimensional image.
0:46:59 > 0:47:03You see, she's got these weird goal-post shaped masts.
0:47:03 > 0:47:05Can you see the rugby posts laying down on the wreck there?
0:47:05 > 0:47:08- Look at that detail.- Gosh, this is just a fantastic program.
0:47:08 > 0:47:13- I just love the fact that you can see inside it.- Yeah, it's great.
0:47:13 > 0:47:18This is a wreck that's changing over time, as the metal rusts,
0:47:18 > 0:47:23as the wooden deck rots and run that change for a few hundred years
0:47:23 > 0:47:27then you end up with just the real skeleton of the ship.
0:47:27 > 0:47:31With new technologies, we can create permanent archaeological records,
0:47:31 > 0:47:36and digitally preserve some of our most significant shipwrecks.
0:47:36 > 0:47:39This is a lovely combination - we've got this great remote sensing tool,
0:47:39 > 0:47:46and we can monitor what's going on and see changes, yet we've still got the personal engagement
0:47:46 > 0:47:49that we all want as divers, and that's to swim down there,
0:47:49 > 0:47:52have a look, and really connect with it.
0:47:52 > 0:47:56And we don't literally have to pick stuff up, and stick it on our mantelpiece,
0:47:56 > 0:47:59your point's well made and I'm converted.
0:48:03 > 0:48:08Our northern waters contain a wealth of maritime history from WWII wrecks,
0:48:08 > 0:48:09to 17th-century merchant ships,
0:48:09 > 0:48:14and all of them can inform us about our past.
0:48:14 > 0:48:20And to understand what's happening in the sea today, we're using even more surprising methods.
0:48:25 > 0:48:29I'm on my way to meet a vet who's got a bit of a mystery to solve.
0:48:29 > 0:48:32There's been a body washed-up on the beach.
0:48:32 > 0:48:33No-one knows the cause of death.
0:48:36 > 0:48:39I've come to Inverness, in the Highlands of Scotland.
0:48:39 > 0:48:44I'm here to meet the team that investigates any mysterious casualties
0:48:44 > 0:48:47that wash up along the coast.
0:48:47 > 0:48:51The Wildlife Unit at the Scottish Agricultural College
0:48:51 > 0:48:55is responsible for investigating some marine deaths.
0:48:58 > 0:49:01- Now then, hiya, Bob. - How are you doing?
0:49:01 > 0:49:07'To determine the cause of an animal's demise, the team perform an autopsy.'
0:49:07 > 0:49:10They conduct around 75 every year
0:49:10 > 0:49:14on creatures ranging from leatherback turtles to whales.
0:49:14 > 0:49:18Their work is crucial in helping to monitor what happens in our seas.
0:49:18 > 0:49:24Their results could reveal anything from an outbreak of disease to marine pollution.
0:49:24 > 0:49:30Wildlife pathologist Dr Andrew Brownlow will be performing today's autopsy.
0:49:30 > 0:49:32Look at this beauty.
0:49:32 > 0:49:36It's still a beauty, even though it's a bit sad looking.
0:49:36 > 0:49:40This bottlenose dolphin was found dead on a beach near Aberdeen.
0:49:40 > 0:49:43But the question is, what killed it?
0:49:43 > 0:49:46Even before we pick up a scalpel blade there's things that we can see
0:49:46 > 0:49:48just from looking at the outside.
0:49:48 > 0:49:52What we've got here are these sort of leaf-like marks.
0:49:52 > 0:49:56- Oh, yeah, what the heck is that, then?- Bird peck marks.
0:49:56 > 0:49:59Ah! So then the birds get on them pretty early, I suppose.
0:49:59 > 0:50:04These rake marks on the back here, these cuts that you can see here.
0:50:04 > 0:50:10And we think these are from other bottlenose dolphin.
0:50:10 > 0:50:12So you can see...
0:50:12 > 0:50:15- a strip here.- Dolphins are known to attack porpoises
0:50:15 > 0:50:19and occasionally have been known to attack their own juveniles.
0:50:19 > 0:50:23So we're going to use a jaw bone for comparison.
0:50:23 > 0:50:25- They match-up fairly well.- Oh, wow.
0:50:25 > 0:50:28So, they are about 11mm apart, which is, roughly speaking,
0:50:28 > 0:50:30the distance between each one of the teeth.
0:50:30 > 0:50:33Yeah, look at that. You can imagine that giving it a good old scrape.
0:50:33 > 0:50:36There are other, similar markings on the dolphin
0:50:36 > 0:50:40but are these wounds significant in understanding the cause of death?
0:50:40 > 0:50:43You can see that this one has begun to heal,
0:50:43 > 0:50:46there is a little bit of evidence of scar tissue around it.
0:50:46 > 0:50:51It's very vague but the chances are that didn't happen at the point at which this animal died.
0:50:51 > 0:50:56From the condition of this animal, we will be able to tell when we actually do the post-mortem,
0:50:56 > 0:50:58but it looks like he's in fairly good nick.
0:50:58 > 0:51:01How are we going to unravel this mystery, then?
0:51:01 > 0:51:03Well, it's not an exact science.
0:51:03 > 0:51:07It's little bits of evidence you put together, this and this, and gradually build-up a picture.
0:51:07 > 0:51:10It's not a "that's what did it".
0:51:10 > 0:51:14I bet. He's pretty heavy.
0:51:14 > 0:51:19From the dolphin's size, Andrew can tell he is less than a year old,
0:51:19 > 0:51:21so he definitely didn't die of old age.
0:51:27 > 0:51:32I'll take a strip off the back so we can measure blubber thickness.
0:51:32 > 0:51:35OK. What can you tell by measuring the blubber thickness, then?
0:51:35 > 0:51:37Condition. Basically. Whether or not it's been feeding,
0:51:37 > 0:51:41I mean, the blubber is an amazing organ,
0:51:41 > 0:51:44it has an insulative capacity - it's energy storage.
0:51:44 > 0:51:46What does your instinct tell you straight away?
0:51:46 > 0:51:49That it's not as thin as some of them that we've seen,
0:51:49 > 0:51:53where they've got no reserves, but it is on the low side.
0:51:53 > 0:51:57From the state of the blubber, it appears that this dolphin
0:51:57 > 0:52:00was not in good condition at the time of its death.
0:52:00 > 0:52:01Actually, you can have a go at this.
0:52:01 > 0:52:04Yeah. I'll have a go. Dead right.
0:52:04 > 0:52:07The bottom bit of this line is probably about level with the spine
0:52:07 > 0:52:10so all of this is muscle, this is the powerhouse,
0:52:10 > 0:52:13this is what's required to get the propulsion through the water.
0:52:13 > 0:52:17Right. This is the engine room I'm coming into, then.
0:52:17 > 0:52:19This is the bit where if you are doing this on a big whale,
0:52:19 > 0:52:22everyone is standing back because this is the bit that explodes.
0:52:22 > 0:52:24Oh, I see. I can imagine, actually.
0:52:24 > 0:52:26Nice. That's really good.
0:52:26 > 0:52:29You can see the organs, we've got the kidney here.
0:52:29 > 0:52:31Yeah. Look at that liver there as well.
0:52:31 > 0:52:33- That's the liver right? - Absolutely. You can do my job.
0:52:33 > 0:52:35I'll go get the coffee.
0:52:35 > 0:52:39Each one of the dolphin's internal organs are removed
0:52:39 > 0:52:43and examined, but they all appear to be normal.
0:52:43 > 0:52:45Further laboratory tests confirmed this.
0:52:45 > 0:52:49- There we go.- Fantastic I'm holding one set of ribs.
0:52:49 > 0:52:53Removing the rib cage may reveal broken bones, evidence of trauma
0:52:53 > 0:52:57that led to its death, such as being hit by a boat.
0:52:57 > 0:52:59Feel that. No fractures.
0:52:59 > 0:53:01Oh, I see. That's clever.
0:53:01 > 0:53:02So what we're checking for...
0:53:02 > 0:53:06So you can see in there if there is any injury to that at all and there is none?
0:53:06 > 0:53:09There's nothing broken so it's unlikely to be a trauma case.
0:53:09 > 0:53:11OK.
0:53:11 > 0:53:15The next stage is to check the stomach contents for more clues.
0:53:18 > 0:53:23- Absolutely empty of food. - It hasn't been eating.
0:53:23 > 0:53:27- It acutely hasn't been eating. - It probably means it hasn't fed for at least a few days.
0:53:27 > 0:53:31- At least a few days. Right. - It's a bit suspicious, something's not looking quite as rosy here.
0:53:31 > 0:53:36Maybe it wasn't quite in as good condition as we thought it was.
0:53:36 > 0:53:40- So the plot thickens. - Yeah, I'll say.
0:53:40 > 0:53:43I'm going to try and take the entire respiratory system out.
0:53:43 > 0:53:50An examination of the lungs reveals this young dolphin was still alive when it stranded on the beach.
0:53:50 > 0:53:55What happens is they come in, they are not too good but they are still alive, they fall onto one side.
0:53:55 > 0:54:00So you end-up with these asymmetric lungs, one will be probably smaller than the other.
0:54:00 > 0:54:03If you see that, you get the idea that it's a live stranding.
0:54:03 > 0:54:06So the animal's come onto the beach alive, and then it's died there.
0:54:06 > 0:54:09So we now know where he died.
0:54:09 > 0:54:14- But we still don't know why. Next? - So we've got here now...
0:54:14 > 0:54:17Oh, wow, feel that! That's amazing.
0:54:17 > 0:54:21What am I... What is it? A great, hard, curved lump.
0:54:21 > 0:54:26Right what you should be feeling here is the back
0:54:26 > 0:54:32of a completely smooth, completely flat and completely non-indented
0:54:32 > 0:54:35ventral column of the spine. What you're feeling is...
0:54:35 > 0:54:38- A whopping great U-bend almost. - Is a big dipper.
0:54:38 > 0:54:41This is absolutely amazing.
0:54:41 > 0:54:42This is nuts. We do not...
0:54:42 > 0:54:45- I mean I've never seen anything like this before.- Right.
0:54:45 > 0:54:50Andrew thinks he now has a complete picture of the circumstances
0:54:50 > 0:54:52surrounding the dolphin's death.
0:54:52 > 0:54:59I'm fairly confident that this seems to be a young animal that maybe got separated from its mother.
0:54:59 > 0:55:03- The stomach was empty, it wasn't managing to feed properly. - It's all coming together.
0:55:03 > 0:55:08This huge deformity is most likely the reason it live stranded, simply
0:55:08 > 0:55:13because it was unable to keep up and it was unable to swim.
0:55:13 > 0:55:15Right. Thank you very much.
0:55:15 > 0:55:18Well, there's a mystery solved.
0:55:18 > 0:55:21We know this young dolphin died stranded on the beach
0:55:21 > 0:55:24and we know it has a massive spinal deformity.
0:55:24 > 0:55:29And we think it's likely that when he left his mother and started to look after himself
0:55:29 > 0:55:35he couldn't keep up with the pod and when he got into trouble, he couldn't get out of it.
0:55:37 > 0:55:41Back on Britain's North Sea, our expedition to understand the success
0:55:41 > 0:55:45- of our gannet population is coming to a close.- It was fascinating.
0:55:45 > 0:55:48We went out with the trawler.
0:55:48 > 0:55:52When the catch comes on board, of course it's not all prawns, it's other stuff there,
0:55:52 > 0:55:56and the fishermen are chucking it overboard and what's eating it? It's the gannets.
0:55:56 > 0:56:00That ties in exactly with what we were talking about with the scientist on the rock.
0:56:00 > 0:56:04What their results are showing is that the gannets are feeding on fish
0:56:04 > 0:56:08that live far deeper than they can actually physically dive.
0:56:08 > 0:56:11- Because the trawlermen are bringing it up.- Precisely.
0:56:11 > 0:56:17I really love these gannets, they are adapting to whatever food is going and I say good on them!
0:56:19 > 0:56:24The fact that the gannet population is doing so well now doesn't quite mean their future is secure.
0:56:27 > 0:56:32These chicks were born about five weeks ago and they need to put on weight quickly
0:56:32 > 0:56:37because come August, their first flying experience will be when they take a tumble off this rock.
0:56:37 > 0:56:42It's a tough start to life for a gannet, so much so that three quarters of these chicks
0:56:42 > 0:56:44will die before they reach independence.
0:56:47 > 0:56:51But life could be about to get even harder for these chicks.
0:56:51 > 0:56:55The European Union is considering introducing new legislation
0:56:55 > 0:56:59banning fishing trawlers throwing their by-catch back into the sea.
0:56:59 > 0:57:03Gannet research scientist Dr Keith Hamer is concerned.
0:57:03 > 0:57:08Do you think that's set to have a negative impact on the gannet population?
0:57:08 > 0:57:11That's one of the things we are concerned about for the future.
0:57:11 > 0:57:14If birds have to be away that little bit longer, that might mean chicks
0:57:14 > 0:57:16might start being left unattended more and more.
0:57:16 > 0:57:18If the chicks are then left unattended, what the non-breeders
0:57:18 > 0:57:23will try to do is move in and attack the chick and kill it and then take over the site.
0:57:23 > 0:57:29And the danger is then that attacks by non-breeders could start to become a serious problem.
0:57:29 > 0:57:34So, in the immediate future, the gannet population here on Bass Rock
0:57:34 > 0:57:40might well suffer if the EU enforces a ban on throwing back by-catch.
0:57:40 > 0:57:44But in the longer term, any measures that help fish stocks recover
0:57:44 > 0:57:49will benefit not just the adaptable gannet but the wider seabird population.
0:57:51 > 0:57:57Gannets are thriving because they've made smart adaptations to the forces of nature and the impact of mankind.
0:57:57 > 0:58:01And they've done that by flying further and diving deeper.
0:58:01 > 0:58:05And last but not least are their fabulous opportunistic feeding habits.
0:58:09 > 0:58:13Next time on Britain's Secret Seas, we uncover the power of the east.
0:58:13 > 0:58:18Pitting a free diver against the natural ability of the grey seal.
0:58:18 > 0:58:23Look at the smooth, efficient way that she's moving, moving just as the seals do.
0:58:23 > 0:58:25Harnessing the force of the wind...
0:58:25 > 0:58:30The winds here are twice as strong as the global average.
0:58:32 > 0:58:35And getting to grips with the future of our lobsters.
0:58:35 > 0:58:39It's like they are just wielding these two massive boxing gloves!
0:58:47 > 0:58:52Subtitles by Red Bee Media Ltd
0:58:52 > 0:58:56E-mail subtitling@bbc.co.uk