Latest / How To Protect The Ocean / The Great Bait Ball: Unraveling the 10 Million Capelin Predation Event

Transcript

The Great Bait Ball: Unraveling the 10 Million Capelin Predation Event · How To Protect The Ocean

• 0:00
  Here's a fact. Cod eat capelin. It's a pretty known
• 0:03
  fact. That's the main predator of capelin, whether it's on
• 0:06
  the east coast of North America, especially in the
• 0:09
  northeast coast, or if it's off the coast of Norway in
• 0:13
  the Atlantic. cod eat capelin. But
• 0:16
  just imagine how much. Because
• 0:20
  today we're going to be talking about one of the
• 0:23
  biggest predation events ever witnessed. It was back in 2014, so
• 0:27
  almost 10 years ago, where 10 million
• 0:31
  capelin were eaten by 2 million cod.
• 0:35
  Imagine witnessing that. Imagine seeing
• 0:39
  that for the first time and really thinking about how
• 0:42
  does this happen on a regular. How does
• 0:46
  this happen where it sustains the population? Well, I'm going to tell you how,
• 0:49
  and I'm going to tell you that the entire population of Capelin in that ball during
• 0:53
  that event was 23 million. So just under 50% were
• 0:57
  eaten. But does this happen often somewhere else? And
• 1:00
  what's going to happen with climate change? How's this going to be affected? And is
• 1:04
  this a problem for Capelin in the future? We're going to be talking about
• 1:07
  that all in today's episode of the How to Protect the Ocean podcast. Let's
• 1:11
  start the show. Hey
• 1:15
  everybody, welcome back to another exciting episode of the How to Protect the Ocean podcast.
• 1:19
  I'm your host Andrew Luen, and this is the podcast where you find out what's happening with the
• 1:22
  ocean, how you can speak up for the ocean, and what you can do to live for
• 1:25
  a better ocean by taking action. If you're here now listening
• 1:29
  to this podcast, or you listen to it any number
• 1:32
  of times, or if this is your first episode, this is the resource
• 1:36
  to find out everything that's happening with ocean conservation and ocean science
• 1:40
  around the world. This is the place. You are in the
• 1:43
  right place. You can find more information on what's happening around the world in
• 1:47
  ocean conservation by going to speakupforblue.com. That's
• 1:51
  speakupforblue.com. And if you want to find out how
• 1:55
  to get information to your inbox Monday to Friday.
• 1:59
  So having three news articles, the latest podcast, the
• 2:02
  latest videos that we put out, as well as the latest job posts that
• 2:05
  we find on the internet, you can sign up for free
• 2:09
  by going to speakupforblue.com forward slash
• 2:13
  newsletter. That's speakupforblue.com forward slash
• 2:17
  newsletter. Let's get into the show. The ocean's largest
• 2:21
  predation event ever recorded by oceanographers.
• 2:24
  And it wasn't by a whale. It wasn't by a shark.
• 2:28
  It was by cod. It was by Atlantic cod
• 2:33
  eating their main prey diet, capelin. And
• 2:36
  in this study that was just published recently, oceanographers
• 2:41
  from MIT and Norway published a study
• 2:44
  after observing a staggeringly large predation event.
• 2:49
  In 2014, in the Barents Sea off the coast of Norway, over
• 2:53
  10 million fish were eaten in just a few hours. sort
• 3:04
  of spawning event so essentially what happens is the capelin come in
• 3:08
  and they start swimming on their own they're just chilling they're
• 3:11
  swimming on their own and after a while they start to dive deep
• 3:15
  and they dive deep and as they dive deep they get closer and closer together
• 3:19
  and then more get closer and closer together until they form probably
• 3:23
  the largest bait ball you've ever seen. Now
• 3:26
  capelin are used for a number of different things. They
• 3:30
  are used for fish bait, they're used
• 3:33
  for as fertilizer, they're used as food as
• 3:37
  a food source for select communities and so they're
• 3:41
  You know, they're used quite a bit, but they do tend to have these bait
• 3:44
  balls, and a lot of times you'll see it. They're very, like, anchovy-like fish, so they're very small.
• 3:47
  They're probably about this big. They're Arctic fish. They're normally
• 3:51
  in the North Atlantic or here in the Barents Sea, and
• 3:55
  they like the cold water. They like to dive deep. They like to be in a bait ball.
• 3:59
  Why do they go in this bait ball? It's to protect themselves. So,
• 4:02
  the fish in the middle will be protected from predators
• 4:06
  from the outside, and the fish on the outside are a bit altruistic, meaning
• 4:09
  that they're probably going to get eaten. There's a good chance they're probably going
• 4:13
  to get affected, damaged, you know, hurt in some sort of way, or
• 4:16
  just eaten in general, because they're on the outside of this massive bait
• 4:19
  ball. Now, when I say massive, I'm talking about 10 kilometers
• 4:24
  long. That's how big, that's how much, like 23 million
• 4:29
  fish in one area, 10 kilometers long. That's
• 4:32
  how many there were. And 10 million of those were eaten by approximately
• 4:37
  2 million codfish. Now you're probably wondering, how do you count? all of
• 4:40
  those, Andrew, like that doesn't make sense. You don't just have someone, you're just
• 4:44
  counting all the fish. No, this was done by a specific instrument
• 4:49
  that's called the Ocean Acoustic Waveguide Remote Sensing System,
• 4:52
  so the O-A-W-R-S. I don't know if it's called ORS or
• 4:56
  what have you. Scientists, we love our acronyms, right?
• 5:01
  But it was recorded a decade ago during an exploratory trip where
• 5:05
  a team of scientists used this sonic imaging technique
• 5:08
  known as the acoustic waveguide remote sensing system.
• 5:12
  This acoustic ray attached to the bottom of the vessel where it
• 5:16
  sends sound waves in all directions. Those waves
• 5:19
  are bounced off anything and everything in their
• 5:23
  path. So if there's fish in the way or there's anything, it bounces off. Now,
• 5:27
  like another set of acoustic receivers picks up the
• 5:30
  reflected sounds, giving the viewer an idea of
• 5:33
  what's happening for miles around. So it's on a screen. It's almost like how
• 5:37
  they do seismic surveys. When they send an acoustic
• 5:41
  sound to the bottom of the ocean, it bounces up. And depending
• 5:44
  on how it hits and how it reflects back, you get to see these
• 5:48
  pockets of sort of like hydrocarbon pockets, right, where you
• 5:51
  want to see oil and gas. In this case, you're seeing fish. Now, how
• 5:54
  do we tell between different species of fish? Well, it just so
• 5:58
  happens that cod have swim bladders. The swim bladders allow
• 6:02
  them to float in the water column, so they're not always sinking like
• 6:05
  a lot of these sharks, but you have these swim bladders.
• 6:09
  Cod have bigger swim bladders than the
• 6:13
  capelin. So when a cod has a low resonance, like
• 6:17
  a big bend bell, whereas capelin have tiny swim
• 6:20
  bladders, so the resonance tends to be high-pitched notes like piano.
• 6:24
  you get the difference in the pitches as they come back and the computer
• 6:28
  is able to decipher between those pitches. And if you just do a
• 6:31
  little bit of programming, these are MIT people here. I'm not sure
• 6:35
  what background the people in Norway have, but the MIT people
• 6:38
  have this coding experience and they're able to decipher between
• 6:42
  and show how big these bait balls are, how
• 6:45
  big the population of each of these different species are. So
• 6:49
  that was kind of cool. So the MIT paper goes
• 6:52
  on, and I'll link to the article in the show notes, but the MIT paper
• 6:56
  goes on to explain that the data was collected during the very
• 7:00
  heat of Capeland's spawning season. So as
• 7:03
  the array pinged off, Often in the early morning hours, they
• 7:06
  were seen to be moving mostly as individuals along
• 7:10
  the coast of Norway. As the day progressed, however, they swam
• 7:13
  deeper, perhaps in an effort to avoid the
• 7:16
  light of the rising sun, so they're not seen. But I think, and
• 7:20
  this is a quote from, I
• 7:24
  don't know who. But one of the people, it says,
• 7:27
  the team observed that as the capelin descended, they
• 7:30
  began shifting from individual to group behavior, individually
• 7:35
  forming a huge shoal of about 23 million fish that
• 7:38
  moved in a coordinated wave spanning over 10 kilometers
• 7:42
  long. That is huge. I would
• 7:46
  love to see sort of like a bait ball that much, or
• 7:50
  that much of a shoal of fish, because
• 7:53
  that's just cool. A shoal of fish is essentially a school of fish, but just in the large
• 7:56
  area and very compact. And soon the master shoal began swimming
• 8:00
  as one, a behavior seen in other fish and some flocks
• 8:04
  of birds. So just imagine a flock of birds, as
• 8:08
  they switch directions, they all switch directions. And the cod in
• 8:11
  the area responded, forming a shoal of their own of over 2 million strong.
• 8:15
  The cod began systematically attacking. Macris,
• 8:19
  who was one of the scientists on
• 8:22
  the study, he says it's the first
• 8:26
  time seeing predatory prey interaction on a huge scale, and it's
• 8:29
  a coherent battle of survival. So this is happening over
• 8:33
  a monster scale, and we're watching a wave of
• 8:36
  capelin zoom in, like a wave around a sports stadium, and
• 8:40
  they kind of gather together to form a defense. It's
• 8:44
  also happening with predators coming together to coherently attack.
• 8:50
  This is unprecedented. We've never really had the chance to
• 8:53
  observe such a large-scale predatory event like this.
• 8:57
  We've seen bait balls before, never in the 10 millions that
• 9:01
  we've seen. So this is great to be able to have this
• 9:04
  data in now. What we worry about in the
• 9:08
  long run is how these bait balls are going
• 9:11
  to be affected by climate change. We know fish
• 9:14
  spawning, we know currents changing, climate
• 9:18
  change, it all gets affected with climate
• 9:21
  change, right? So heating of the oceans, switching of
• 9:25
  currents and wind patterns in the ocean and in the atmosphere can
• 9:29
  really change how things are done and how
• 9:33
  things work and function within the ocean. you
• 9:36
  know it's the small fish when their larvae they get taken by
• 9:40
  the currents to another place and that that pattern is
• 9:44
  dependent on by predators and prey itself
• 9:48
  to run their regular life cycle as those change during
• 9:51
  climate change or throughout climate change this will
• 9:55
  change the pattern and may affect, whether short-term or long-term, whether
• 9:58
  it's gonna be capelin success in reproduction or the
• 10:02
  cod success in predating these
• 10:06
  fish, this prey, right, these capelins. So it
• 10:10
  could be a problem when we see these massive bait balls. As the
• 10:13
  team said, the study team said, it's like, once we get the last bait
• 10:17
  ball and we know it's the last population and we know
• 10:20
  it's gonna be a mass feeding and predation population event,
• 10:25
  Once they're gone, they're gone. If they don't recover fast enough to
• 10:28
  take on 10 million, or however many get
• 10:32
  eaten at that one time, that bait
• 10:36
  ball, that population will not recover in time. It is dependent
• 10:40
  on numbers. It's a numbers game. So if those numbers aren't successful
• 10:44
  in having 10 million more offspring, or more
• 10:48
  of that, or less, if it's less, then we know that the cod population is
• 10:51
  gonna go down. So that's, you know, these and other
• 10:55
  predators that depend on capelin as well. It's all going
• 10:58
  to be affected. It's all in a food web and it's all negatively responding
• 11:02
  or positively responding depending on how much reproduction we see on
• 11:06
  a daily, on a annual basis, semi-annual basis, you
• 11:10
  know, every couple of years. This is the
• 11:13
  problem with climate change. This is the problem with any kind of environmental disturbance
• 11:17
  that we see, is will we have more capelin to
• 11:20
  be able to witness these massive feeding events?
• 11:24
  I don't know. I haven't read the full study yet. I don't know if
• 11:28
  there have been other events after that, that it shows a pattern of
• 11:32
  these massive 10 million, this 10 million feeding
• 11:35
  event, but That's pretty cool. That's
• 11:39
  pretty cool to see it and be able to recover after that. So hopefully we'll see more
• 11:42
  recovery. I know in certain places like off the coast of Canada, capelin
• 11:46
  are in a critical point as well as cod is
• 11:49
  just over a critical point, but like slightly. And
• 11:53
  you know, there's been an increase in fishing for cod, Atlantic cod
• 11:57
  off the Atlantic coast of Canada. And so there's
• 12:00
  an opening of that. That could be dangerous as well. So these, these fish
• 12:04
  populations are not, You know,
• 12:08
  they're not unlimited. There is a limit to each one.
• 12:11
  They can go down in population depending on what happens. Climate change
• 12:14
  is rearing its ugly head faster and faster than we've ever seen. So
• 12:18
  we don't know how this is going to affect this fish population. I'll
• 12:21
  try and get more information and maybe try and get an interview. to talk about
• 12:25
  the capelin-cod-predation-prey relationship
• 12:29
  on that side of the Atlantic and be able to bring
• 12:33
  that back to you. But I thought it was an interesting story. I
• 12:37
  wanted to bring it to you because I think it's something that we should
• 12:40
  share together. And I'd love to hear your thoughts on it. Have
• 12:43
  you ever heard of this before? Have you ever seen any more studies?
• 12:47
  Who's working on this? I would love to hear. And what you think of
• 12:50
  the content of the topic of this $10 million strong
• 12:55
  bait ball. 23 million bait ball, but 10 million being consumed in less
• 12:58
  than a few hours. I think that's amazing. I want to hear your
• 13:02
  thoughts. You can hit me up on a comment on Spotify, on
• 13:05
  YouTube, or you can hit me up on Instagram at howtoprotecttheocean. Just
• 13:09
  send me a DM that's at how to protect the ocean. I
• 13:12
  would love to hear your thoughts on the podcast, the thoughts on this episode,
• 13:16
  and just your thoughts in general relating to ocean conservation and
• 13:20
  science. Feel free to contact me, ask me any kind of questions, I'd be more than happy to
• 13:23
  answer it either here or to you directly. I want to thank you
• 13:26
  so much for joining me on this episode of the How to Protect the Ocean podcast. Have