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The Biggest Mouthful: How Blue Whales Eat and Why Krill Matters · How To Protect The Ocean

• 0:00
  I want you to picture a blue whale, 30 meters long, 200 meters down,
• 0:04
  closing in on a swarm of krill so thick it looks like a huge cloud.
• 0:09
  The whale beats its tail, picks up a bunch of speed, and opens its mouth.
• 0:13
  In about the time it takes you to read a text message, it swallows a volume
• 0:17
  of water bigger than its own body.
• 0:19
  And the move only pays off when the krill is thick.
• 0:23
  And here's the kicker.
• 0:24
  The lunge move that these massive whales do only works when the krill is thick,
• 0:29
  like that cloud is thick of full of krill.
• 0:32
  And the krill is something we're catching more often every year as humans.
• 0:36
  And that's gonna be the focus of this episode.
• 0:38
  And the next four episodes, we're gonna be focusing on the biology
• 0:42
  of the biggest whales and what that biology tells us about protecting them.
• 0:47
  And we talked yesterday with Ashley Blawas, who is a postdoc talking
• 0:51
  about whales and lunge feeding and the heart rates and everything.
• 0:53
  We're gonna dive deep into that in this series for the next four episodes
• 0:57
  because I think it's important this week to talk about the physiology of these
• 1:01
  large mammals because it's fun to know.
• 1:02
  And it has a little bit of, connection with us as humans.
• 1:06
  So I think it's interesting to look at that.
• 1:08
  And most of us, grew up with the idea that whales were, quote-unquote
• 1:11
  saved, back in the 1980s when commercial whaling was paused.
• 1:15
  And then you hear about ship strikes and entanglements and climate change, and you
• 1:18
  start to wonder if the comeback is real or are we gonna go on a downward trend?
• 1:23
  So this episode starts with the most basic question about a giant
• 1:26
  whale: How does it eat enough to have its large body stay alive?
• 1:30
  And once you see that answer, you see exactly where the pressure points are
• 1:34
  and exactly where the good news is.
• 1:37
  I've spent 15 years talking to people who study whales, and the thing that always
• 1:41
  gets me is how much of a whale's life comes down to one single meal done right.
• 1:46
  So to understand the threat, you first need to picture the meal.
• 1:50
  Blue whales, fin whales, and humpbacks belong to a group called rorquals.
• 1:54
  So the word comes from the Old Norse term of translated as furrow whale
• 1:59
  because of the long grooves running down their throats and bellies.
• 2:02
  Those grooves are the secret.
• 2:04
  The skin and blubber on the rorquals underside is pleated like an
• 2:07
  accordion, and it runs about half or 60% of the whale's body length.
• 2:12
  When the whale opens its mouth at speed, water rushes in and those pleats stretch
• 2:16
  out like a balloon filling with water.
• 2:18
  And a blue whale can take in a volume of water bigger than
• 2:21
  its own body in a single gulp.
• 2:23
  Then it closes its mouth, pushes all that water out through the baleen, the
• 2:27
  fringe plates, the hanging from its upper jaw, and the water leaves, the
• 2:31
  krill stays, and the whale swallows.
• 2:33
  A scientist who modeled the energy of a blue whale lunge found that one gulp
• 2:37
  cost the whale somewhere between about 3,000 and 8,000 kilojoules of energy.
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  In a thin patch of krill, the whale gets about six times what it spent.
• 2:47
  In a thick, dense swarm cloud, it gets back more than 200 times what it spent.
• 2:52
  So the same whale, same lunge, the only thing that changes how tightly
• 2:55
  the food was packed in those clouds.
• 2:58
  Now giant whale doesn't survive on oceans average, it survives on finding the
• 3:02
  densest swarms and hitting them hard.
• 3:05
  They gotta eat most of that swarm.
• 3:07
  A blue whale in the Eastern North Pacific can eat about 16 tons of
• 3:10
  krill a day when it's feeding.
• 3:12
  So if the whole strategy depends on dense swarms of krill, what's the problem?
• 3:16
  We're gonna talk about it right now.
• 3:18
  Antarctic krill are small shrimp-like animals about half
• 3:20
  the length of your finger.
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  They gather in swarms so dense that they can tint the water, and they
• 3:25
  feed penguins, seals, fish, seabirds, and the biggest whales on earth.
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  They also feed an industry.
• 3:31
  So the fishing vessels in the Southern Ocean catch krill for omega-3 supplements
• 3:35
  for feed on salmon farms and for pet food.
• 3:38
  The international body that manages the fishery is the Commission for
• 3:41
  the Conservation of Antarctic Marine Living Resources, or the CCAMLR.
• 3:46
  It's a lot to say.
• 3:48
  And it set a precautionary ceiling back in 1991.
• 3:51
  It's called the trigger level, so 620,000 of tons a year.
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  That's as much as they can catch.
• 3:57
  And for more than three decades, the fisheries never reached it.
• 3:59
  But in 2005 it did.
• 4:01
  The fleet hit 620,000 tons by early August, and the season closed months ahead
• 4:07
  of the schedule for the first time ever.
• 4:09
  This total isn't only a concern.
• 4:11
  A rule that spread the catch out across areas lapsed the year before.
• 4:14
  So in waters in the Antarctic Peninsula, the catches went past 355,000 tons, more
• 4:19
  than double the old limit for that area.
• 4:22
  These are the same waters where humpbacks and other whales come to feed.
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  Phil Trathan, a longtime Antarctic ecosystem scientist, pointed out
• 4:29
  that the commission does not have any mechanism in place to monitor baleen
• 4:32
  whales even though whales likely eat more krill in that area than anything else.
• 4:37
  Now a fishing fleet goes where krill is densest, and so does a lunge feeder.
• 4:42
  They are hunting in the same exact swarms.
• 4:45
  Now, the industry says the closure shows the system is working as designed.
• 4:48
  They have a quota, they met that quota, they shut it down.
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  And both things can be true.
• 4:53
  The limit held and the limit was set before anyone knew
• 4:55
  how much whales could eat.
• 4:57
  I wanna talk about something that scientists figured out that changes
• 5:00
  the thinking about all this.
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  In the 20th century, industrial whaling killed somewhere between
• 5:04
  two and three million whales with most of the krill eaters gone.
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  So people expected the Southern Ocean to fill up with krill, but it didn't.
• 5:11
  Krill numbers seemed to fall instead.
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  In 2021, a team of scientists put tags on 321 whales and measured
• 5:17
  how much they actually eat.
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  They found baleen whales eat about three times more than older estimates.
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  And when whales eat,
• 5:24
  they also poop near the surface, where it could act as fertilizers for the ocean.
• 5:28
  Whale poop is rich in iron, and iron is the nutrient that limits plankton
• 5:31
  growth in much of the Southern Ocean.
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  So before whaling, the team estimated Southern Ocean whales recycled
• 5:37
  about 12,000 tons of iron a year.
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  Today, it's around 1,200 tons, about one tenth of that amount.
• 5:44
  More plankton means more krill.
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  More krill means more food for whales.
• 5:48
  The whales were helping grow the very swarms that they actually ate.
• 5:52
  Nicholas Pyenson, a Smithsonian scientist on this study, put it this
• 5:55
  way: "If we restore whale populations to pre-whaling levels, we'll restore the
• 6:00
  huge amount of lost function to the ocean.
• 6:03
  Whales play a more important role than we actually think.
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  They help farm their own food.
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  That's the strongest reason to protect swarms they feed on.
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  Now here's an example.
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  South Georgia is a remote island in the South Atlantic,
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  east of the Falkland Islands.
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  In the early 1900s, its waters were full of blue whales,
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  these massive, massive animals.
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  So whaling stations of course, were built on its shores.
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  Between 1904 and 1971, whalers killed 42,698 blue whales off South Georgia.
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  Most of them died before the mid-1930s.
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  By the end, the blue whales were gone.
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  From 1998 to 2018, survey after survey recorded exactly one blue
• 6:39
  whale sighting in those waters.
• 6:41
  Scientists began to treat South Georgia as the textbook case of a population
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  hunted past the point of return.
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  The lead author of a later study, Susanna Calderon, described it as an
• 6:51
  iconic example of a population that was locally exploited beyond recovery.
• 6:56
  Then, in February 2020, a research team went back.
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  In three weeks of surveys, they recorded 58 blue whale sightings.
• 7:03
  Their underwater microphones picked up blue whale calls again and again.
• 7:07
  And then they compared photos of 41 blue whales seen around South Georgia
• 7:10
  over the previous decade with a catalog of 517 known Antarctic blue whales.
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  None of them matched.
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  These were new whales finding their way back to feeding grounds their
• 7:20
  species had used for thousands of years.
• 7:23
  Now, the return took about 50 years after the last whaling station closed.
• 7:27
  And it's because whales are slow to recover, and they do recover
• 7:30
  when they have food and space.
• 7:31
  But you gotta remember, these are large animals.
• 7:33
  They don't just reproduce like fish, where, they put out, like,
• 7:36
  millions of eggs, and then, those get fertilized, they get a higher
• 7:40
  fecundity, so higher reproduction rate.
• 7:42
  These whales will, give birth to calves.
• 7:44
  Those calves have to reach sexual maturity, which takes a long time.
• 7:46
  They will reproduce.
• 7:47
  And it takes a long time for these whales to recover because
• 7:50
  of their slow life history.
• 7:51
  Antarctic blue whale populations are still a small fraction of what they once were.
• 7:56
  And the krill fishery is legal and is regulated.
• 7:58
  The question is now is whether the rules keep up with what we
• 8:01
  know about how much whales eat.
• 8:04
  And this is not just the fact of these fishers are taking away
• 8:07
  the krill cause of the whales.
• 8:09
  It's the fact of, hey, we know these whales actually will produce more krill.
• 8:13
  When we now know that these whales will produce the food that
• 8:16
  will help the krill survive, and that will help grow the krill.
• 8:19
  We keep taking the krill, and we don't allow the whales to
• 8:22
  recover, then that whole loop, that feedback loop just gets destroyed,
• 8:27
  And the fact is, like, we don't just have a lack of blue whales happening here.
• 8:31
  We have other things that are happening.
• 8:33
  Krill face warming seas, shrinking sea ice which young krill rely
• 8:37
  on, and the whales can't afford to share the shrinking pantry.
• 8:41
  So the fact is, is your call to action for this episode is skip the krill oil.
• 8:45
  If you take an omega-3 supplement, choose one that's made from algae.
• 8:50
  Fish get their omega-3s from eating algae in the first place, so algal-based
• 8:53
  supplements go straight to the source.
• 8:56
  If you start to think about how you can get and how you can save the planet, is
• 9:00
  get away from those types of omega-3 fatty acids and go towards the algae-based ones.
• 9:05
  It's just the same.
• 9:06
  You won't even taste the difference, and you'll still get your omega-3 fatty acids.
• 9:10
  Now every capsule of krill oil starts as a krill swarm.
• 9:13
  That swarm is, same dense patch a blue whale needs to make its lunge pay off.
• 9:18
  Most of the krill catch goes to farm fish feed, which is harder for one
• 9:22
  person to change, but the supplement aisle is the piece you control directly,
• 9:27
  you can do that even today.
• 9:29
  Next time you buy that supplement, Go towards that algae-based
• 9:31
  instead of animal-based.
• 9:33
  So you think about it, in South Georgia we had one sighting in 20
• 9:36
  years, then we had 58 in three weeks.
• 9:38
  These blue whales will recover if we give them time and we
• 9:41
  get them to have their food.
• 9:44
  Them having their food equals more krill in the long run, blue whales, lunging
• 9:48
  into krill swarms in the same waters where their species was nearly erased.
• 9:52
  This is what is important.
• 9:54
  They almost got hunted to extinction.
• 9:56
  The recovery takes a little bit longer.
• 9:58
  Krill swarms are going down 'cause we are trying to catch them more.
• 10:00
  We have a quota, but the thing is, is now that the blue whales have been gone, it
• 10:04
  has been harder to reproduce those krill.
• 10:06
  They have no food provided for the phytoplankton, which the
• 10:09
  phytoplankton is food for the krill.
• 10:11
  So the biggest animal that ever lived only needs two things to come back.
• 10:14
  They need room to swim and a swarm worth opening its mouth for.
• 10:17
  That's really what it comes down to.
• 10:19
  Now that's the episode for today.
• 10:20
  Tomorrow we're gonna follow that whale down a dive and listen to
• 10:24
  its heartbeat, it does something that no human heart could survive.
• 10:27
  We're gonna talk about that on next episode.
• 10:29
  But until then, if you have a question about this episode and you're listening
• 10:32
  to it on Spotify, hit me in the comments.
• 10:34
  I would love to hear about that.
• 10:35
  I check those all the time.
• 10:37
  As soon as I get a comment, I get an alert, so I'd love to chat back.
• 10:40
  And of course, if you're listening to this on your favorite podcast app that
• 10:43
  doesn't allow comments, which is too bad 'cause I really like that feedback
• 10:46
  area, you can hit me up on my socials.
• 10:47
  The links are in the show notes.
• 10:49
  I wanna thank you for watching this episode of the How to
• 10:51
  Protect the Ocean podcast.
• 10:52
  I'm your host, Andrew Lewin.
• 10:53
  Have a great day.
• 10:54
  We'll talk to you tomorrow, and happy conservation.