How do you save a shark you know nothing about? - Simon Berrow

Lastly, sharks are awesome creatures. They are just magnificent. They grow 10 meters long; some say bigger. They might weigh up to two tons; some say up to five tonnes. But the second largest fish in the world, they're also harmless plankton-feeding animals, and they are thought to be able to filter a cubic kilometer of water every hour. They can feed on 30 kilos of zooplankton a day to survive.

They're fantastic creatures, and we're very lucky in Ireland that we have plenty of basking sharks and plenty of opportunities to see them. They were also very important to coastal communities going back hundreds of years, especially the rounded-off Connemara region, where subsistence farmers used to sail out on their hookers and from boats, sometimes way offshore, sometimes for a place called Sunfish Bank, which is about 30 miles west of Akal Island, to kill the basking sharks.

This now would cut from about the 17-1800s; it's known to be very important. They are important for the oil out of their liver. A third of the size of a basking shark is the liver, and it's full of oil. You can get gallons of oil from the liver, and that oil was used specially for lighting, but also for dressing wounds and other things. In fact, the street lights in 1742 of Galway, Dublin, and Waterford were lit with sunfish. Sunfish is one of the words for basking sharks, so they're incredibly important animals.

They've been around a long time. They're very important to coastal communities. Probably the best-documented basking shark fishery in the world is that from Akal Island. This is Keene Bay, up in Akal Island, and sharks used to come into the bay. The fishermen would tie a net off the headland, string it out, an old manila net, and as a shark came round, they would hit the net. The net would collapse on it; it often drowned and suffocated. At times, they would row out in their small kirk's and kill it with a lance through the back of the neck, and then they towed the sharks back to 13 Harbor, boiled them up, and used the oil. They also used the flesh as well for fertilizer and also wood thinly fin the sharks.

This is probably the biggest threat to sharks worldwide: it is the finning of sharks. We often hear about sharks and jaws; maybe five or six people get killed by sharks every year. There was some one reason there wasn't; there were just a couple to go. We kill about 100 million sharks a year, so you know, all the balances. But I think sharks have got more right to be fearful than us, and we have of them. It was a well-documented fishery, and you can see here it peaked in the fifties, where they were killing 1,500 sharks a year, and in decline very fast—a classic boom-bust fishery—which suggests that the stock has been depleted or there's low reproductive rates.

They killed about 12,000 sharks in this period, literally just by stringing a manila rope off the tip of Keene Bay. The Netherland sharks were still killed up into the mid-80s, especially after places like Don Morrison, County Waterford. About two and a half, three thousand sharks were killed up to '85, made by Norwegian vessels. The black, you can't see this, but it's in Norwegian basking shark hunting vessels, and the black line in the crow’s nest signifies this is a shark vessel rather than a whaling vessel.

The importance of basking sharks to the coastal communities is recognized through the language. I don’t pretend to have any Irish, but there's a term in Kerry: they were often known as 'the Mede' and the shelter of the monster with the sails. Another title would be 'lapa'—our 'lappa,' the unwieldy beasts with two fins, suggesting a big animal. But my favorite is 'Leabhar an Choire,' meaning 'the great fish of the surfing.' That's a lovely evocative name.

In Tory Island, which is a strange place anyway, they were known as Muldoon’s, and no one seems to know why. There's no one from Tory here; lovely place! But more commonly, all around the island, they were known as the Sunfish, and this represents their habit of basking on the surface when the sun is out.

There's great concern that basking sharks are depleted all throughout the world. Some people say it's not a population decline; it might be a change in the distribution of plankton. It's been suggested the basking sharks would make fantastic indicators of climate change because they're basically continuous plankton recorders swimming around with the mouth open.

They're now listed as vulnerable under the IUCN. There's all sorts of moves in Europe to try and stop catching them. There's now a ban on catching them and even landing them accidentally. They're not protected in Ireland; in fact, they have no protective status in Ireland whatsoever despite our importance for the species and the historical context with which basking sharks reside. We know very little about them, and most of what we do know is based on their habit of coming to the surface. We try and guess what they're doing from the behavior on the surface.

I only found out last year at a conference in the Isle of Man just how unusual it is to live somewhere where basking sharks regularly, frequently, and predictably come to the surface. It's a fantastic opportunity for a scientist to see them and experience basking sharks. I have; they are awesome creatures. But it gives us a fantastic opportunity to actually study them, to get access to them.

What we've been doing the last couple of years—last year was a big year—is we started tagging sharks so we could try and get some idea of site fidelity and movements and things like that. We concentrated mainly in North Donegal and West Kerry, the two areas where I was mainly active, and we tagged them very simply—not very high-tech—with a big long pole. This is a beach tester rod for the tag on the end. Then we would go up in our boat and tag the shark, and we were very effective.

We tagged 105 sharks last summer. We got 50 in three days off Inis Meain Peninsula. Half the challenge is to get access; it's to be in the right place at the right time. But it's a very simple and easy technique.

I'll show you what they look like. We use a pole camera on the boat to actually film the shark. One is to try and work out the gender of the shark. We also deployed a couple of satellite tags, so we did use high-tech stuff as well.

These are archival tags, so what they do is they store the data. A satellite tag only works when the area is clear of the water and can send a signal to the satellite. Of course, sharks, fish are underwater most of the time. This tag actually works out the location of the shark depending on the time of day, the setting of the sun, plus water temperature and depth.

You have to kind of reconstruct the path. What happens is that you set the tag to detach from the shark after a fixed period; in this case, it was eight months. At midday, the tag popped off, drifted up, sent its signal to the satellite, and sent not all the data, but enough data for us to use.

This is the only way of really working out behavior and movements when they're underwater. Here are a couple of maps that we've done. That one you can see was taken off Kerry, and it basically spent all its time the last eight months in Irish waters. On Christmas Day, it was out on the shelf edge.

And here's one that we haven't ground-truthed yet with Caesar, the temperature, and water depth. But again, the second shark kind of spent most of its time in and around the Irish Sea. Colleagues in the Isle of Man last year actually tagged one shark, and it went in the Isle of Man all the way out to Nova Scotia in about 90 days—over nine and a half thousand kilometers. We never thought that would happen.

Another colleague in the States tagged about 20 sharks off Massachusetts, and his tag didn't really work. All he knows is where he tagged them and where they popped off. His tags popped off in the Caribbean and even in Brazil, and we thought the basking sharks were temperate animals; they lived in our latitudes for a natural fact. They're obviously crossing the equator as well.

So a very simple thing like that, we stood up to try and learn more about basking sharks. One thing that I think is very surprising and a strange thing is just how low the genetic diversity of sharks is. Now, I'm a geneticist, so I'm not going to pretend to understand genetics, and that's why it's great to have collaboration, whereas I'm a field person; I get patterns.

It's a panic attack if I have to spend too many hours in a lab with a white coat on—take me away! So, we can work with geneticists who understand that. When they look at the genetics of basking sharks, they found that the diversity was incredibly low. If you look at the first line, you can see that all these different shark species are all quite similar.

I think this means basically they’re all sharks that come from a common ancestry, but if you look at nucleotide diversity, which is more genetic, sort of passed on through the parents, you can see that basking sharks have, look at the first study, one order of magnitude less diversity than another shark species. You can see this was presented in 2006.

Before 2006, we had no idea of the genetic variability of basking sharks. We had no idea did they distinguish into two different populations; were there subpopulations? Of course, that's very important if you want to know what the population size is and the status of the animals.

So there’s a Nobel prize in Aberdeen who found this a bit unbelievable really. So he did another study using microsatellites, which is much more expensive, much more time-consuming, and to his surprise came up with almost identical results. So it does seem to be that basking sharks, for some reason, have incredibly low diversity.

It's thought maybe there was a bottleneck, a genetic bottleneck, thought to be twelve thousand years ago, and this has caused a very low diversity. Yet if you look at the whale shark, which is the other plankton-eating larger shark, its diversity is much greater. So it doesn't really make sense at all.

They found that there was no genetic differentiation between any of the world's oceans of basking sharks. So even though basking sharks are found throughout the world, you couldn’t tell the difference genetically from one in the Pacific, from the Atlantic, from New Zealand, or from Ireland, South Africa. They all basically seem the same, which again is kind of surprising. You wouldn't really expect that.

I don't understand this; I don't pretend to understand this, and I suspect most geneticists don’t understand it either. But they produce the numbers so you can actually estimate the population size based on the diversity of the genetics. Ross also came up with a population effective size: eight thousand, two hundred animals; that’s it—eight thousand animals in the world.

You're thinking that’s just ridiculous. No way! LEDs did a finer study and found it came out about nine thousand. Using different microsatellites gave you different results. But the average of all these studies came out—the mean is about five thousand, which, you know, I personally don’t believe. But then I am a skeptic. But even if you toss a few numbers around, you’re probably talking about an effective population of about twenty thousand animals.

Remember how many they killed back in the fifties and sixties! So what it tells us is that there’s actually a risk of extinction of this species because its population is so small. In fact, of those twenty thousand, eight thousand were thought to be females. So then there are eight thousand basking shark females in the world. I don't know; I don't believe it.

The problem with this is they were constrained with samples. They didn't get enough samples to really explore the genetics in enough detail. So where do you get samples from for your genetic analysis? Well, one obvious source is dead sharks—sharks washed up. We might get two or three dead sharks washed up in Ireland a year if we’re lucky.

Another source would be fisheries bycatch; we were getting quite a few caught in surface drift nets. That’s now banned, and that'll be good news for sharks. Someone caught a net in trawlers; this is a shark that was actually landed in a house just before Christmas illegally because you're not allowed to do that under EU law. It was actually sold for eight euros a kilo as the sharks. They even put a recipe up on the wall until they were told this was illegal, and they actually did get a fine for that.

So if you look at all those studies I showed you, the total number of samples worldwide is 86 at present. So it's very important work, and they can ask really good questions, and they can talk to us about population size and subpopulations and structure. But they’re constrained by lack of samples.

Now when we were out tagging our sharks, this is how we tagged them. On the front of a rib, get in there fast. Occasionally, the shark does react. One occasion when we were up in Malin Head, a big shark smacked the side of the boat with its tail. More, I think, in start of the fact that a boat came near it rather than the tank going in.

That was fine; we got wet, no problem. When myself and Emma got back to Malin Head to the pier, I noticed some black slime on the front of the boat. I remembered spending a lot of time out on commercial fishing boats; I remember fishing telling me they can always tell when a basking shark's been caught in the net because it leaves this black slime behind.

I was thinking, well that must have come from the shark. Now, we had an interest in getting tissue samples for genetics because we knew they were very valuable, and we would use conventional methods. I have a crossbow to see across with in my hand, which we used to sample whales and dolphins for genetic studies as well.

So I tried that; I tried many techniques. All in all, he was doing was breaking my arrows because the shark's skin is just so strong. There was no way we were going to get a sample from that, so that wasn’t going to work. When I saw the black slime on the bow of the boat, I thought, well, you know, if you take what you're given in this world.

So I scraped it off and had a little tube with alcohol in it to send to the geneticist. I scraped the slime off, sent it off to Aberdeen, and I said, you might try that. They sat on it for months; actually, he was only because we were at a conference in the Isle of Man. I kept emailing Les saying, you had a chance to look at that slime yet? You know he's like, yeah, yeah, yeah, later, later, later.

Anyway, they thought, well, they better do it because I've met him before; he might lose face if he hadn't done the thing I sent him. He was amazed that they actually got DNA from the slime, amplified it, tested it, and found yes, this was actually basking shark DNA.

It was taken, and they were all very excited. He became known as 'Simon's Shark Slime,' and I thought, hey, you know, I can build on this. We thought, well, ok, we're gonna try and get out and get some slime. Having spent three and a half thousand on satellite tags, I then thought I’d invest 795 in a pricey salon at my local hardware store in Purush for a mop handle and even less money on some oven cleaners.

I wrapped the oven cleaner around the end of the mop handle and was desperate—desperate to have an opportunity to get some sharks. This was into August now, and there weren't very many sharks. They usually kind of peak in June or July, and you rarely see them; you really can be in the right place to find sharks in August, and so we were desperate.

We rushed out to the last case as soon as we heard there were sharks there and managed to find some. By just rubbing the mop handle down the shark as it swam under the boat, as you see here, we managed to collect slime. Here is a look at that lovely black shark slime. In about half an hour, we got five samples from five individual sharks using Simon's Shark Slime Sampling System.

I’ve been working with whales and dolphins in Ireland for 20 years now, and you know they’re kind of always a bit more dramatic. You probably saw the humpback whale footage that we got a month or two ago off County Wexford, and you know, you always think you might have some legacy you can leave the world behind a lot of sleep enough how about whales breaching and dolphins? But hey, you know, sometimes these things are sent to you, and you just have to take them when they come.

So this is possibly gonna be my legacy: Simon's Shark Slime. We've got more money actually this year to carry on collecting more and more samples, and one thing that is kind of very useful is we use pole cameras in college around. With a pole camera, you can actually look underneath the shark, and what you're trying to look at is the males' claspers, which kind of dangle out behind the back of the shark.

So you can quite easily tell the gender of the shark. If we can tell the gender of the shark before we sample it, we can be more intelligent ethicists since we're taking it from a male or a female because at the moment they actually have no way genetically to obtain a difference in a male or a female, which I find absolutely staggering because they don't know what primers to look for.

Being able to tell the gender of a shark is very important for things like policing the trade-in shark basking shark and other species through the CITES. It is illegal to trade in these sharks, and they are caught and they are in the market.

So as a field biologist, you just want to get encounters with these animals. You want to learn as much as you can. They're often quite brief; they often vary seasonally constrained, and you just want to learn as much as you can as soon as you can. But isn't it fantastic that you can then offer these samples and opportunities to other disciplines, such as geneticists, who can gain so much more from that?

So, as I said, these things essentially, in strange ways, you grab them while you can. You know, I'll take that as my scientific legacy. Hopefully, I might get something a bit more dramatic and romantic before I die, but for the time being, thank you for that, and keep an eye out for sharks. If you're more interested, we have a basking shark website now just set up. Thank you, and thank you for listening.