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← Are we interrupting the kinky sex lives of fish?

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Showing Revision 8 created 05/26/2020 by Erin Gregory.

  1. Right now,
  2. beneath a shimmering blue sea,
  3. millions of fish are having sex.
  4. (Cheers)

  5. And the way they're doing it
    and strategies they're using

  6. looks nothing like what we see on land.
  7. Take parrotfish.

  8. In this species, all fish are born female,
  9. and they look like this.
  10. Then later in life,
  11. she can transition into a male
    and she'll look like this.
  12. But it's not just
    a spectacular wardrobe change.
  13. Her body can reabsorb her ovaries
    and grow testes in their place.
  14. In just a few weeks,
  15. she'll go from making eggs
    to producing sperm.
  16. It's pretty impressive,
  17. and in the ocean it's also pretty common.
  18. In fact, I bet nearly all of you
    have at some point had a seafood dish
  19. made up of an individual
    that started life as one sex
  20. and transitioned to another.
  21. Oysters?
  22. Grouper?
  23. Shrimp?
  24. Seeing some heads nodding, yeah.
  25. But not all fish that change sex
    start as females.

  26. Those clown fish we know
    from "Finding Nemo"?
  27. They're all born male.
  28. So in the real world,
  29. when Nemo's mother died,
  30. Nemo's dad Marlin
    would have transitioned into Marlene --
  31. (Laughter)

  32. and Nemo would have likely mated
    with his father turned mother.

  33. (Laughter)

  34. You can see --

  35. (Laughter)

  36. Yeah.

  37. You can see why Pixar
  38. took a little creative license
    with the plotline, right?
  39. (Laughter)

  40. So sex change in the ocean
    can happen in either direction

  41. and sometimes even back and forth,
  42. and that's just one of the many
    amazing strategies animals use
  43. to reproduce in the ocean.
  44. And trust me when I say
  45. it's one of the least surprising.
  46. Sex in the sea is fascinating,

  47. and it's also really important,
  48. and not just to nerdy
    marine biologists like me
  49. who are obsessed with understanding
    these salty affairs.
  50. It matters for all of us.
  51. Today, we depend on wild caught fish
  52. to help feed over two billion people
  53. on the planet.
  54. We need millions of oysters and corals
    to build the giant reefs
  55. that protect our shorelines
    from rising seas and storms.
  56. We depend on medicines that are found
    in marine animals to fight cancer
  57. and other diseases.
  58. And for many of us,
  59. the diversity and beauty of the oceans
    is where we turn for recreation
  60. and relaxation and our cultural heritage.
  61. In order for us to continue
    to benefit from the abundance
  62. that ocean life provides,
  63. the fish and coral and shrimp of today
  64. have to be able to make fish
    and shrimp and coral for tomorrow.
  65. To do that, they have to have
    lots and lots of sex.
  66. And until recently,

  67. we really didn't know
    how sex happened in the sea.
  68. It's pretty hard to study.
  69. But thanks to new science and technology,
  70. we now know so much more
    than even just a few years ago,
  71. and these new discoveries
    are showing two things.
  72. First, sex in the sea is really funky.
  73. Second, our actions are wreaking havoc
    on the sex lives of everything
  74. from shrimp to salmon.
  75. I know. It can be hard to believe.
  76. So today, I'm going to share a few details
    about how animals do it in the deep,
  77. how we may be interrupting
    these intimate affairs
  78. and what we can do to change that.
  79. So, remember those sex-changing fish?

  80. In many places in the world,
  81. we have fishing rules
    that set a minimum catch size.
  82. Fishers are not allowed
    to target tiny fish.
  83. This allows baby fish to grow
    and reproduce before they're caught.
  84. That's a good thing.
  85. So fishers go after the biggest fish.
  86. But in parrotfish, for example,
    or any sex changer,
  87. targeting the biggest fish means
    that they're taking out all the males.
  88. That makes it hard for a female fish
  89. to find a mate
  90. or it forces her to change sex sooner
  91. at a smaller size.
  92. Both of these things can result
    in fewer fish babies in the future.
  93. In order for us to properly care
    for these species,
  94. we have to know if they change sex,
  95. how and when.
  96. Only then can we create rules
    that can support these sexual strategies,
  97. such as setting a maximum size limit
    in addition to a minimum one.
  98. The challenge isn't that we can't think
    of these sex-friendly solutions.
  99. The challenge is knowing
    which solutions to apply to which species,
  100. because even animals we know really well
  101. surprise us when it comes
    to their sex lives.
  102. Take Maine lobster.

  103. They don't look that romantic,
  104. or that kinky.
  105. They are both.
  106. (Laughter)

  107. During mating season,

  108. female lobsters want to mate
    with the biggest, baddest males,
  109. but these guys are really aggressive,
  110. and they'll attack any lobster
    that approaches, male or female.
  111. Meanwhile, the best time
    for her to mate with the male
  112. is right after she's molted,
  113. when she's lost her hard shell.
  114. So she has to approach this aggressive guy
    in her most vulnerable state.
  115. What's a girl to do?
  116. Her answer?
  117. Spray him in the face
    repeatedly with her urine.
  118. (Laughter)

  119. Under the sea, pee
    is a very powerful love potion.

  120. Conveniently, lobsters' bladders
    sit just above their brains,
  121. and they have two nozzles
    under their eye stalks
  122. with which they can shoot
    their urine forward.
  123. So the female approaches the male's den
  124. and as he charges out
    she lets loose a stream of urine
  125. and then gets the hell out of there.
  126. Only a few days of this daily dosing
  127. is all it takes for her scent
    to have a transformative effect.
  128. The male turns from an aggressive
    to a gentle lover.
  129. By the week's end,
    he invites her into his den.
  130. After that, the sex is easy.
  131. So how are we interrupting
    this kind of kinky courtship?

  132. Well, the female's urine
    carries a critical chemical signal
  133. that works because
    it can pass through seawater
  134. and lobsters have a smell receptor
  135. that can detect and receive the message.
  136. Climate change is making
    our oceans more acidic.
  137. It's the result of too much
    carbon dioxide entering seawater.
  138. This changing chemistry
    could scramble that message,
  139. or it could damage
    the lobsters' smell receptors.
  140. Pollution from land
    can have similar impacts.
  141. Just imagine the consequence
    for that female
  142. if her love potion should fail.
  143. These are the kinds of subtle
    but significant impacts we're having
  144. on the love lives of these marine life.
  145. And this is a species we know well:

  146. lobsters live near shore in the shallows.
  147. Dive deeper, and sex gets even stranger.
  148. Fanfin anglerfish live at about
    3,000 feet below the surface
  149. in the pitch-black waters,
  150. and the males are born
    without the ability to feed themselves.
  151. To survive, he has to find a female fast.
  152. Meanwhile, the female,
  153. who is 10 times bigger than the male,
  154. 10 times,
  155. she lets out a very strong pheromone
    with which to attract mates to her.
  156. So this tiny male is swimming
    through the black waters
  157. smelling his way to a female,
  158. and when he finds her,
  159. he gives her a love bite.
  160. And this is when things get really weird.
  161. That love bite triggers
    a chemical reaction
  162. whereby his jawbone
    starts to disintegrate.
  163. His face melts into her flesh,
  164. and their two bodies start to fuse.
  165. Their circulatory systems intwine,
  166. and all his internal organs
    start to dissolve
  167. except for his testes.
  168. (Laughter)

  169. His testes mature just fine
    and start producing sperm.

  170. In the end, he's basically
    a permanently attached
  171. on-demand sperm factory for the female.
  172. (Laughter)

  173. It's a very efficient system,

  174. but this is not the kind
    of mating strategy
  175. that we see on a farm, right?
  176. I mean, this is weird.
  177. It's really strange.
  178. But if we don't know
    that these kinds of strategies exist
  179. or how they work,
  180. we can't know what kind of impacts
    we may be having, even in the deep sea.
  181. Just three years ago,
  182. we discovered a new species
    of deep sea octopus
  183. where the females lay their eggs
    on sponges attached to rocks
  184. that are over two and a half miles deep.
  185. These rocks contain rare earth minerals,
  186. and right now there are companies
    that are building bulldozers
  187. that would be capable of mining
    the deep sea floor for those rocks.
  188. But the bulldozers
    would scrape up all the sponges
  189. and all the eggs with them.
  190. Knowingly, and in many cases unknowingly,
  191. we are preventing successful sex
    and reproduction in the deep.
  192. And let's be honest,
  193. dating and mating is hard enough
    without somebody coming in
  194. and interrupting all the time, right?
  195. I mean, we know this.
  196. So today, while I hope you will leave here

  197. with some excellent bar trivia
    on fish sex --
  198. (Laughter)

  199. I also ask that you remember this:

  200. we are all far more intimately connected
    with the oceans than we realize,
  201. no matter where we live.
  202. And this level of intimacy
  203. requires a new kind
    of relationship with the ocean,
  204. one that recognizes and respects
    the enormous diversity of life
  205. and its limitations.
  206. We can no longer think of the oceans
  207. as just something out there,
  208. because every day we depend on them
    for our food security,
  209. our own health and wellness,
  210. and every other breath we take.
  211. But it is a two-way relationship,
  212. and the oceans can only continue
    to provide for us
  213. if we in turn safeguard
    that fundamental force of life in the sea:
  214. sex and reproduction.
  215. So, like any relationship,
    we have to embrace some change

  216. for the partnership to work.
  217. The next time you're thinking
    about having seafood,
  218. look for sustainably caught
    or farmed species
  219. that are local and low on the food chain.
  220. These are animals
    like oysters, clams, mussels,
  221. small fish like mackerel.
  222. These all reproduce like crazy,
  223. and with good management,
    they can handle a bit of fishing pressure.
  224. We can also rethink
    what we use to wash our bodies,
  225. clean our homes
  226. and care for our lawns.
  227. All of those chemicals
    eventually wash out to sea
  228. and disrupt the natural chemistry
  229. of the ocean.
  230. Industry also has to play its part
  231. and take a precautionary approach,
  232. protecting sexual activity
    where we know it exists
  233. and preventing harm in the cases
    where we just don't yet know enough,
  234. like the deep sea.
  235. And in the communities where we live,
  236. the places we work
  237. and the country in which we vote,
  238. we must take bold action
    on climate change now.
  239. (Audience: Yeah!)

  240. (Applause)

  241. Thank you.

  242. (Applause)