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Showing Revision 5 created 10/11/2016 by Brian Greene.

  1. Basking sharks are awesome creatures.
  2. They are just magnificent.
  3. They grow 10 meters long; some say bigger.
  4. They might weigh up to two tons.
  5. Some say up to five tons.
  6. They're the second-largest
    fish in the world.
  7. They're also harmless
    plankton-feeding animals.
  8. And they are thought to be able to filter
    a cubic kilometer of water every hour
  9. and can feed on 30 kilos
    of zoo plankton a day to survive.
  10. They're fantastic creatures.
  11. We're very lucky in Ireland,
  12. we have plenty of basking sharks
    and plenty of opportunities to study them.
  13. They were very important
    to coastal communities,

  14. going back hundreds of years,
  15. especially around
    the Claddaghduff, Connemara region
  16. where subsistence farmers used to sail
    out on their hookers and open boats,
  17. sometimes way offshore
    to a place called the Sunfish Bank,
  18. about 30 miles west of Achill Island,
  19. to kill the basking sharks.
  20. This is a woodcut from about the 1800s.
  21. They were very important,
    for the oil out of their liver.

  22. A third of the basking
    shark's size is their liver,
  23. and it's full of oil, gallons of oil.
  24. That oil was used especially for lighting,
  25. but also for dressing wounds
    and other things.
  26. In fact, the streetlights in 1742,
  27. of Galway, Dublin and Waterford,
  28. were lit with sunfish oil.
  29. "Sunfish" is one of the words
    for basking sharks.
  30. So they were incredibly important animals.
  31. They've been around a long time,
    very important to coastal communities.
  32. Probably the best-documented
    basking shark fishery in the world

  33. is that from Achill Island.
  34. This is Keem Bay up in Achill Island.
  35. Sharks used to come into the bay,
  36. and the fishermen
    would tie a net off the headland,
  37. string it out, an old Manila net,
  38. and as the shark came round,
    it would hit the net,
  39. the net would collapse on it.
  40. It would often drown and suffocate.
  41. Or at times, they would row out
    in their small curraghs
  42. and kill it with a lance
    through the back of the neck.
  43. And then they'd tow the sharks
    back to Purteen Harbour,
  44. boil them up, use the oil.
  45. They also used the flesh
    as well, for fertilizer
  46. and also would fin the sharks.
  47. This is probably the biggest threat
    to sharks worldwide --
  48. the finning of sharks.
  49. We're often frightened
    of sharks, thanks to "Jaws."

  50. Maybe five or six people
    get killed by sharks every year.
  51. There was someone recently, wasn't there?
    Just a couple weeks ago.
  52. We kill about 100 million sharks a year.
  53. So I don't know what the balance is,
  54. but I think sharks have more right
    to be fearful of us than we have of them.
  55. It was a well-documented fishery.
  56. As you can see here,
    it peaked in the '50s,
  57. where they were killing
    1,500 sharks a year.
  58. And it declined very fast --
    a classic boom-and-bust fishery,
  59. which suggests that a stock
    has been depleted
  60. or there's low reproductive rates.
  61. They killed about 12,000 sharks
    within this period,
  62. literally just by stringing a Manila rope
  63. off the tip of Keem Bay
    up in Achill Island.
  64. Sharks were still killed
    up into the mid-80s,

  65. especially out of places
    like Dunmore East in County Waterford.
  66. About two and a half, 3,000
    sharks were killed up till '85,
  67. mainly by Norwegian vessels.
  68. You can't really see,
  69. but these are Norwegian
    basking shark hunting vessels.
  70. The black line in the crow's nest
    signifies this is a shark vessel,
  71. rather than a whaling vessel.
  72. The importance of basking sharks
    to the coast communities

  73. is recognized through the language.
  74. I don't pretend
    to [know many Irish words],
  75. but in Kerry they were often
    known as "ainmhide Na seolta,"
  76. "the monster with the sails."
  77. Another title would be "liop an dá lapa,"
  78. "the unwieldy beast with two fins."
  79. "Liabhán mór," suggesting a big animal.
  80. Or my favorite, "liabhán chor gréine,"
    "the great fish of the sun."
  81. That's a lovely, evocative name.
  82. On Tory Island -- a strange place
    anyway -- they were known as "muldoons."
  83. (Laughter)

  84. No one seems to know why.

  85. Hope there's no one
    from Tory here. Lovely place.
  86. But more commonly all around the island,
    they were known as the sunfish.
  87. And this represents their habit
    of basking on the surface
  88. when the sun is out.
  89. There's great concern
    that basking sharks are depleted

  90. all throughout the world.
  91. Some say it's not population decline,
  92. it might be a change
    in the distribution of plankton.
  93. It's been suggested
  94. that these sharks would make
    fantastic indicators of climate change,
  95. as they're basically
    continuous plankton recorders,
  96. swimming around with their mouth open.
  97. They're now listed
    as vulnerable under the IUCN.
  98. There's movements in Europe
    to try and stop catching them.
  99. There's now a ban on catching
    and even landing them,
  100. even landing ones caught accidentally.
  101. They're not protected in Ireland;
  102. in fact, they have no legislative
    status in Ireland whatsoever,
  103. despite our importance for the species
  104. and also the historical context
    within which basking sharks reside.
  105. We know very little about them.

  106. And most of what we do know
  107. is based on their habit
    of coming to the surface --
  108. we try and guess what they're doing
    from their behavior on the surface.
  109. I only found out last year,
    at a conference on the Isle of Man,
  110. just how unusual it is to live somewhere
  111. where basking sharks regularly,
    frequently and predictably
  112. come to the surface to "bask."
  113. It's a fantastic opportunity
    for a scientist
  114. to see and experience basking sharks.
  115. They are awesome creatures.
  116. It gives us a fantastic opportunity
    to study them, to get access to them.
  117. What we've been doing for a couple
    years -- last year was a big year --

  118. is we started tagging sharks,
  119. so we could try to get some idea
    of sight fidelity and movement
  120. and things like that.
  121. So we concentrated mainly
    in North Donegal and West Kerry
  122. as the two areas
    where I was mainly active.
  123. And we tagged them
    very simply, not very high-tech,
  124. with a big, long pole.
  125. This is a beachcaster rod
    with a tag on the end.
  126. You go up in your boat and tag the shark.
  127. And we were very effective.
  128. We tagged 105 sharks last summer.
  129. We got 50 in three days
    off Inishowen Peninsula.
  130. Half the challenge to get access

  131. is to be in the right place
    at the right time.
  132. But it's a very simple, easy technique;
    I'll show you what it looks like.
  133. We use a pole camera on the boat
    to actually film the shark.
  134. One, it's to try and work out
    the gender of the shark.
  135. We also deployed some satellite tags,
    so we did use high-tech stuff as well.
  136. These are archival tags.
  137. What they do is store the data.
  138. A satellite tag only works
    when the air is clear of the water
  139. and can send a signal to the satellite.
  140. And sharks and fish
    are underwater most of the time,
  141. so this tag actually works out
    the locations of shark,
  142. depending on the timing
    and the setting of the sun,
  143. plus water temperature and depth.
  144. And you have to kind of
    reconstruct the path.
  145. What happens is,

  146. you set the tag to detach
    from the shark after a fixed period --
  147. in this case, eight months --
  148. and literally to the day,
    the tag popped off,
  149. drifted up, said hello to the satellite
  150. and sent, not all the data,
    but enough data for us to use.
  151. This is the only way to really work out
    their behavior and movements
  152. when they're underwater.
  153. And here's a couple
    of maps that we've done.

  154. In that one, you can see
    that we tagged both off Kerry.
  155. Basically, it spent all its time,
    the last eight months, in Irish waters.
  156. On Christmas, it was out
    on the shelf edge.
  157. Here's one we haven't ground-truthed yet
  158. with sea-surface temperature
    and water depth,
  159. but again, the second shark
    spent most of its time
  160. in and around the Irish Sea.
  161. Colleagues from the Isle of Man
    last year actually tagged one shark
  162. that went from the Isle of Man
    to Nova Scotia in about 90 days.
  163. Nine and a half thousand kilometers --
    we never thought that happened.
  164. Another colleague in the States
    tagged about 20 sharks off Massachusetts.

  165. His tags didn't really work.
  166. All he knows is where he tagged them,
  167. and where they popped off.
  168. His tags popped off in the Caribbean,
  169. and even in Brazil.
  170. We thought basking sharks
    were temperate animals
  171. and lived in our latitudes,
  172. but in actual fact, they're obviously
    crossing the equator as well.
  173. So very simple things like that,

  174. we're trying to learn
    about basking sharks.
  175. One thing that I think
    is a very surprising and strange thing
  176. is just how low the genetic
    diversity of sharks is.
  177. I'm not a geneticist, so I won't pretend
    to understand the genetics.
  178. And that's why it's great
    to have collaboration.
  179. Whereas I'm a field person,
  180. I get panic attacks
  181. if I have to spend too many hours
    in a lab with a white coat on.
  182. Take me away.
  183. So we can work with geneticists
    who understand that.
  184. So when they looked at
    the genetics of basking sharks,
  185. they found that the diversity
    was incredibly low.
  186. If you look at the first line, really,

  187. you can see that all these different
    shark species are all quite similar.
  188. I think this means they're all sharks
  189. and they've come from a common ancestry.
  190. But if you look at nucleotide diversity,
  191. which is more genetics
    that are passed on through the parents,
  192. you see that basking sharks,
    if you look at the first study,
  193. was order of magnitude less diverse
    even than other shark species.
  194. You can see this work
    was only done in 2006.
  195. Before 2006, we had no idea of the genetic
    variability of basking sharks.

  196. We had no idea: Did they distinguish
    into different populations?
  197. Were there subpopulations?
  198. And that's very important
    if you want to know
  199. what the population size is,
    and the status of the animals.
  200. So, Les Noble in Aberdeen kind of found
    this a bit unbelievable, really.
  201. So he did another study
    using microsatellites,
  202. which is much more expensive,
    much more time-consuming,
  203. and to his surprise,
    came up with almost identical results.
  204. So it does seem to be
    that basking sharks, for some reason,

  205. have incredibly low diversity.
  206. And it's thought maybe
    it was a genetic bottleneck,
  207. thought to have been 12,000 years ago,
  208. and this has caused a very low diversity.
  209. And yet, if you look at the whale shark,
  210. which is the other
    plankton-eating large shark,
  211. its diversity is much greater.
  212. So it doesn't really make sense at all.

  213. They found that there was
    no genetic differentiation
  214. between any of the world's oceans
    of basking sharks:
  215. even though they're found
    throughout the world,
  216. you couldn't tell
    the difference, genetically,
  217. from one from the Pacific, Atlantic,
    New Zealand, Ireland, South Africa.
  218. They all basically seem the same.
  219. Which, again, is kind of surprising;
    you wouldn't expect that.
  220. I don't understand or pretend
    to understand this;
  221. I suspect most geneticists don't either,
  222. but they produce the numbers.
  223. So you can actually estimate
    the population size

  224. based on the diversity of the genetics.
  225. And Rus Hoelzel came up with
    an effective population size:
  226. 8,200 animals.
  227. That's it -- 8,000 animals in the world.
  228. You're thinking,
    "That's ridiculous. No way."
  229. So Les did a finer study,
  230. and he found out it came out about 9,000.
  231. Using different microsatellites
    gave the different results,
  232. but the mean of all these
    studies is about 5,000,
  233. which I personally don't believe.
  234. But then, I am a skeptic.
  235. But even if you toss a few numbers around,
  236. you're probably talking an effective
    population of about 20,000 animals.
  237. Do you remember how many they killed
    off Achill in the 70s and the 50s?
  238. So what it tells us, actually,
  239. is that there's actually a risk
    of extinction of this species
  240. because its population is so small.
  241. In fact, of those 20,000,
  242. 8,000 were thought to be females.
  243. There's only 8,000 basking shark
    females in the world?
  244. I don't know. I don't believe it.
  245. The problem with this
    is they were constrained with samples.

  246. They didn't get enough samples
  247. to really explore the genetics
    in enough detail.
  248. So, where do you get samples from
    for your genetic analysis?
  249. Well, one obvious source is dead sharks --
  250. dead sharks, washed up.
  251. We might get two or three dead sharks
    washed up in Ireland a year,
  252. if we're kind of lucky.
  253. Another source would be
    fisheries' bycatch.
  254. We were getting quite a few caught
    in surface drift nets.
  255. That's banned now, and that'll be
    good news for the sharks.
  256. And some are caught in nets, in trawls.
  257. This is a shark that was actually
    landed in Howth just before Christmas --
  258. illegally, because you're not allowed
    to do that under EU law --
  259. and was actually sold
    for eight euros a kilo as shark steak.
  260. They even put a recipe up on the wall,
  261. until they were told it was illegal.
  262. They actually did get a fine for that.
  263. So if you look at
    all those studies I showed you,

  264. the total number of samples worldwide
  265. is 86, at present.
  266. So it's very important work,
  267. and they can ask
    some really good questions,
  268. and tell us about population size
    and subpopulations and structure,
  269. but they're constrained
    by lack of samples.
  270. When we were out tagging our sharks --

  271. this is how we tagged them on the front
    of a RIB, get in there fast --
  272. occasionally, the sharks do react.
  273. On one occasion, when we were
    up in Malin Head in Donegal,
  274. the shark smacked the side
    of the boat with his tail,
  275. more, I think, in startle to the fact
    that a boat came near it,
  276. rather than the tag going in.
  277. And that was fine. We got wet. No problem.
  278. And then when myself and Emmett
    got back to Malin Head, to the pier,
  279. I noticed some black slime
    on the front of the boat.
  280. I used to spend a lot of time
    on commercial fishing boats,
  281. and I remember fishermen saying
  282. they can tell when a basking shark
    has been caught in a net,
  283. because it leaves a black slime behind.
  284. So that must have come from the shark.
  285. Now, we had an interest
    in getting tissue samples for genetics

  286. because we knew they were very valuable.
  287. We would use conventional methods;
  288. I have a crossbow --
    you see it in my hand there,
  289. which we use to sample whales
    and dolphins for genetic studies as well.
  290. So I tried that, I tried many techniques.
  291. All it was doing was breaking my arrows,
  292. because the shark's skin
    is just so strong.
  293. There was no way we were going
    to get a sample from that.
  294. That wasn't going to work.
  295. So when I saw the black slime
    on the bow of the boat,

  296. I thought, "If you take
    what you're given in this world ..."
  297. So I scraped it off.
  298. I had a little tube with alcohol in it
    to send to the geneticists.
  299. So I scraped the slime off
    and sent it to Aberdeen,
  300. and said, "You might try that."
  301. And they sat on it for months.
  302. It was only because we had
    a conference on the Isle of Man.
  303. But I kept emailing Les, saying,
  304. "Have you had a chance
    to look at my slime?"
  305. And he was like, "Yeah, yeah. Later."
  306. He thought he'd better do it
    because I never met him before;
  307. he might lose face if he hadn't done
    the thing I sent him.
  308. And he was amazed that they actually
    got DNA from the slime.

  309. They amplified it and they tested it,
  310. and they found, yes,
    this was actually basking shark DNA,
  311. which was got from the slime.
  312. So he was very excited.
  313. It became known as "Simon's shark slime."
  314. And I thought, "Hey, you know,
    I can build on this."
  315. So we thought, OK, we're going to try
    to get out and get some slime.
  316. So having spent three-and-a-half
    thousand on satellite tags ...
  317. I then thought I'd invest 7.95 --
    the price is still on it --
  318. in my local hardware store in Kilrush
  319. for a mop handle,
  320. and even less money on some oven cleaners.
  321. And I wrapped the oven cleaner
    around the edge of the mop handle
  322. and ...
  323. (Laughter)

  324. I was desperate to have an opportunity
    to get some sharks.

  325. And this was into August now,
    and normally sharks peak in June, July,
  326. and you rarely see them,
    or rarely can be in the right place
  327. to find sharks into August.
  328. We were desperate,
    so we rushed out to the Blaskets
  329. as soon as we heard
    there were sharks there,
  330. and managed to find some sharks.
  331. So by just rubbing
    the mop handle down the shark
  332. as it swam under the boat --
  333. you see a shark
    running under the boat here --
  334. we managed to collect slime.
  335. And here it is.
  336. Look at that lovely black shark slime.
  337. And in about half an hour,
    we got five samples.
  338. Five individual sharks were sampled
  339. using Simon's Shark Slime Sampling System.
  340. (Laughter)

  341. (Applause)

  342. I've been working on whales and dolphins
    in Ireland for 20 years now,

  343. and they're a bit more dramatic.
  344. You probably saw
    the humpback whale footage
  345. we got a month or two ago
    off County Wexford.
  346. And you always think
    you might have some legacy
  347. you can leave the world behind,
  348. and I was thinking of humpback
    whales breaching and dolphins.
  349. But hey -- sometimes
    these things are sent to you
  350. and you just have to take them
    when they come.
  351. So this is possibly
    going to be my legacy --
  352. Simon's Shark Slime.
  353. We got more money this year

  354. to carry on collecting
    more and more samples.
  355. One thing that is very useful
    is that we use a pole camera --
  356. this is my colleague, Joanne,
    with a pole camera --
  357. where you can look underneath the shark.
  358. What you're trying to look at is,
    the males have claspers,
  359. which kind of dangle out
    behind the back of the shark.
  360. So you can quite easily tell
    the gender of the shark.
  361. If we can tell the gender of the shark
    before we sample it,
  362. we can tell the geneticist
    this was taken from a male or a female.
  363. Because in the moment,
    they have no way, genetically,
  364. of telling the difference
    between a male and a female,
  365. which I find staggering,
  366. because they don't know
    what primers to look for.
  367. Being able to tell the gender of a shark
  368. is very important
    for things like policing the trade
  369. in basking shark and other species
    through the sightings,
  370. because it is illegal
    to trade in these sharks.
  371. And they are caught and are on the market.
  372. So as a field biologist,

  373. you just want to get encounters
    with these animals,
  374. and learn as much as you can.
  375. They're often quite brief,
    they're often very seasonally constrained.
  376. You just want to learn as much
    as you can as soon as you can.
  377. But isn't it fantastic
  378. that you can then offer
    these samples and opportunities
  379. to other disciplines,
    such as the geneticists,
  380. who can gain so much more from that.
  381. So as I said, these things
    are sent to you in strange ways.

  382. Grab them while you can.
  383. I'll take that as my scientific legacy.
  384. Hopefully, I might get something
    a bit more dramatic and romantic
  385. before I die.
  386. But for the time being,
    thank you for that.
  387. And keep an eye out for sharks.
  388. If you're more interested, we have
    a basking shark website now set up.

  389. So thank you and thank you for listening.
  390. (Applause)