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Orcas vs Great White Sharks: How Killer Whales Are Changing Shark Populations · How To Protect The Ocean

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  If orcas keep targeting young, great white sharks, could they actually
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  reshape the future of one of the ocean's most iconic predators?
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  New footage shows orcas hunting juvenile great white sharks in what
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  scientists believes are nursery zones, the very places where this next
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  generation is supposed to grow safely.
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  If these attacks become more common, we're not just watching
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  Predator versus predator.
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  We might be witnessing a shift that could ripple through
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  the entire marine ecosystem.
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  We're gonna talk about all that on today's episode of the How
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  to Protect the Ocean Podcast.
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  Let's start the show.
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  Hey everybody.
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  Welcome back to another exciting episode of the How to Protect the Ocean Podcast.
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  I'm your host, Andrew Lewin, and this is the podcast where you find
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  out what's happening with the ocean, how you can speak up for the ocean,
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  and what you can do to live for a better ocean by taking action.
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  Now, on today's episode, we're gonna be talking about how orcas in Mexico,
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  in Mexican waters are actually hunting juvenile great white sharks.
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  They're predating on a smaller species going after their livers, and we
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  actually have video evidence of that happening that was published recently
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  in Frontiers and Marine Science.
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  We're gonna talk about that today.
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  But before you do, I want to remind you if you saw last episode, you
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  This looks like another population that is predating upon great white sharks.
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  We've seen this before in South Africa.
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  We've seen it potentially in other places, I think in sort of the northeast Pacific,
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  like northwest of the United States.
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  And we've seen it happen where orcas will in a pair
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  One of them will grab a great white shark.
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  The other one will precisely go after their liver, make an
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  incision, pull out their liver.
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  Eat their liver and then they kind of take turns in it depending on
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  where these great white sharks are.
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  We've followed port and Starbird, two orcas that had a pretty big impact on
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  the great white shark population in South Africa, and it's a little controversial
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  of whether that's the reason why there aren't as many great white sharks.
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  In specific bays like Mossel Bay and other places.
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  There's a lot of other things at play at that, but they've definitely had
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  an influence in where these great white sharks are or where they've
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  disappeared to in South Africa.
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  But now we're starting to see, and we have video evidence.
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  Repeated predation of juvenile great whites by orcas in Mexican water.
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  So the authors of this study that was in Frontiers in marine science report
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  two attack events in the Gulf of California, August, 2020 and August,
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  2022, involving a pod of orcas on juvenile great white sharks around.
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  2.5 meters in length.
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  So that's probably, around like the nine feet, maybe a little bit, maybe a little
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  bit less than that rather than the adults that are going after these juvenile areas.
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  Now this adds a new dimension compared to previous observations, which mostly
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  involve adult white sharks, which these orcas are getting better and better.
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  Port starboard have been shown and observed to actually predate
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  upon a great white by themselves.
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  It's not in pairs anymore.
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  It's by themselves going after, you know, 20 footers.
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  These are big sharks now, these juveniles are smaller, as we mentioned
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  before Now, of course in Mexican waters they're smaller animals, so you're
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  probably seeing one orca on each animal.
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  But they're starting to see this happen obviously on more than one occasion, which
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  makes us believe like, Hey, how much is this happening in these nurseries areas?
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  So this is really interesting.
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  So.
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  The orcas use a method of special behavior of flipping the young sharks
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  upside down inducing tonic immobility.
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  When you flip a shark upside down, it kind of paralyzes them, like
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  temporarily immobilizes them.
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  And so when they flip them over, they get uninterrupted access to the shark's liver
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  and perhaps other energy rich organs.
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  But mostly we know they go for the liver, which they consume,
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  and sometimes sharing it among the pod members including the calf.
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  So it could be a way of teaching these calfs how to hunt or even how
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  to like, get a taste for these livers.
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  We know that orcas display interesting characteristics when they hunt.
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  They will put salmon on top of their heads and ride around with
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  salmon on top of their heads.
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  We still don't know the reasons why we think it's more of like
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  a celebration of a good hunt.
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  We're not sure though completely.
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  I know from anecdotal evidence of people that I've heard from.
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  They'll eat moola molars and put the half the moola moola on their head.
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  It's very interesting behavior, odd behavior, but interesting
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  behavior nonetheless.
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  And so we know these sharks go after specialized organs.
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  Sometimes brains, sometimes others parts.
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  The tongue of blue whales, they like to go for when they're in Australia.
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  And so it's a lot of just different things that happen, and the way they, they hunt
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  and they're very specialized in that.
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  But in this way, they flip the sharks over, they immobilize
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  them, they get access to those organs, especially the liver.
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  And then they share among the pod.
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  This has been shown before where they actually will hunt to feed
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  other members of their pod.
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  It shows a level of intelligence and heightened awareness, and I
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  think that's really interesting.
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  Now, of course, the impact images of the dorsal fin markings and repeated
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  behavior point to the same pod of orcas referred to as the Moctezuma a
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  pod, being involved in both events so that they identify the actual
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  pod, so it's the same pod every time.
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  The author suggests that this pod may have a specialization in hunting
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  elasmobranchii sharks and rays in this region beyond typical orca prey.
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  So this is not just like they'll go after marine mammals, they'll go after others.
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  They actually try and go after elasmobranchii Stingrays.
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  Flat sharks, what we like to call them, as well as other sharks like what you
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  see, like great whites and so forth.
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  So I think that's kind of interesting.
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  And then of course, the presence of juvenile white sharks in this region
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  may reflect shifts in the distribution, attributed in part to warming water
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  anomalies such as El Nino events which could bring young sharks into
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  zones where orcas operate regularly.
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  So nursery areas for great white sharks are really still being
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  discovered in specific areas.
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  We know there's a nursery area in Southern California along the
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  west coast of the United States, and of course now we're thinking
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  that there's a nursery area.
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  We don't know the extent of it or if it stays in one area all the time.
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  Just like I mentioned before, El Nino events and other event warming
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  events may shift where these waters are, depending on their food
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  availability for these nurseries.
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  Obviously nursery areas are areas that are gonna be bound with food for these
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  great whites so that they can grow and can go after food that's more their size,
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  more their liking, and that'll be great.
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  But if it comes in areas where there are orcas, which we know
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  there are in the Gulf of California.
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  Then that can actually have an impact on their population.
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  So the authors, they raise concerns of how predator and prey dynamics may
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  change if juveniles are more exposed, and how this might affect the recruitment
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  of great white sharks in the future.
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  They already have slow life history.
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  So an impact like this where if orcas can go in and impact like adults in
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  Southern Africa where you have those huge 20 footers, now you're looking
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  at an area that we're smaller that are growing into and that will spread around
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  the ocean and show like a population that's doing well now may be impacted.
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  They have slow life history, so if there's more animals that get impacted
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  in terms of get eaten, they're not there for the next generation to grow, right?
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  That generation to grow up into adults, which will impact their recruitment,
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  it'll impact their reproductive ability.
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  It'll have lower impact in the future.
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  Hence, that's the concern that happens.
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  And we just don't know if this is gonna happen all the time.
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  We have no idea if this nursery area is gonna be in the same place next
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  year or the year after, or if it's still in the same place this year.
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  This happened in 2020 and 2022, which to be honest, is one of the
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  problems with peer reviewed papers.
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  Although, you wanna make sure everything is great, it's just the
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  writeup, it doesn't happen quick enough.
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  Hopefully they're still observing these areas and the more research
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  will be done to see if this happens over and over again.
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  Or if the nursery areas, these sharks are in the same space, they may
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  have left because of that predation.
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  The ones that are better off surviving may have moved into another area based on
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  prey, also just based on survivability.
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  So we just don't know what's gonna happen to this population.
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  Well, let's be honest, great White sharks have had a boom in population
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  in the United States, on the East coast and on the west coast.
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  We've seen a proliferation of sharks, even in their
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  distribution, has changed as adults.
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  We know the Southern California nursery area, but also adult sharks are going
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  as high as San Francisco Bay, and he may be even higher.
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  On the East coast, it used to be Cape Cod, now they're going up to the Gulf of
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  St. Lawrence in that area in Nova Scotia.
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  So where they're starting to see that move, north as the water's warm
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  and they still within their range.
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  They go out to the Mid-Atlantic bite, they go all the way down to Florida Cape Cod,
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  and now even north into Canadian waters.
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  This is going to be a case where monitoring is still gonna be needed
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  for not only these great whites, but also see what these orcas are
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  eating and where they're going and how the nursery areas are going
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  to change based on warming waters.
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  You know, it's gonna be a lot of oceanography, iss
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  gonna be a lot of ecology.
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  And, see those, distributions warmer water.
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  predator prey kind of relationships, like the prey for the juvenile.
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  Great whites, are they gonna be in the same area?
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  Are they gonna move because of the shift in warming waters?
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  There's a lot to learn from this, but having these two events definitely shows a
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  pattern that may have already been there, or maybe something new just because the
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  orcas are like, Hey, we have new food.
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  This is really rich in nutrients, and we like it, and,
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  we're getting a taste for it.
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  Now, of course, as they're getting a taste for it, will
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  they follow these sharks along?
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  Who knows.
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  Will the Sharks population be affected later on?
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  We don't know at this point, but something that we definitely have to keep an eye on.
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  So, looking at nursery areas, looking at warming, water distribution, looking at
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  predator prey distribution and looking at orca distribution, obviously a predator,
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  the apex predator, it seems very, very smart, and help feeding each other and,
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  members of their pod I think is brilliant.
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  So we're seeing a lot of really cool things that are happening out
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  in the ocean, but also some scary things that can happen in the future.
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  Now, obviously there's gaps.
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  We still don't know how often these interactions occur, the frequency.
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  So how widespread is this behavior among Orca pods and is that
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  happening in elsewhere now that there are more great white sharks?
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  Also it highlights the limitations of regarding how long juvenile white
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  sharks stay in that particular region.
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  Their anti predator responses, where are they gonna go now, as I mentioned
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  earlier and how changing ocean conditions might alter the nursery
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  areas, and the predator overlap.
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  So we'll see what happens.
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  It's a call to action, definitely to have more systemic monitoring
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  of shark nurseries, orca behavior, and shifting habitat overlap.
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  So that's it for today's episode.
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  I'd love to hear what you think about this.
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  Do you think these orcas are gonna affect the great white population in the future?
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  Do you think this is just like an anomaly?
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  It just happened just because everything just kind of came to be for these
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  orcas and the great white sharks, that those juveniles just kind of
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  came in because they're following prey and that will change in the future.
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  I'd love to hear what you have to say, and if you're involved in
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  any of these studies, let me know.
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  I'd love to have more questions for you, but that's it for today's episode.
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• 10:45
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• 10:48
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• 10:51
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• 10:55
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• 10:56
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  I'd love to hear from you.
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  I wanna thank you so much for joining me on today's episode of the
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  How to Protect the Ocean Podcast.
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  I'm your host Andrew Lewin from the True Nord strong and free.
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  Have a great day.
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  We'll talk to you next time and happy conservation.