Feb. 17, 2025
Killer Whales vs. Great White Sharks: Genetic Proof of Predation! 🦈🐋
Did you know that killer whales (Orcinus orca) are taking down great white sharks (Carcharodon carcharias) in South Africa? 🦈🐋 In this video, we break down groundbreaking research that provides genetic evidence of orcas hunting and preying on...
Did you know that killer whales (Orcinus orca) are taking down great white sharks (Carcharodon carcharias) in South Africa? 🦈🐋 In this video, we break down groundbreaking research that provides genetic evidence of orcas hunting and preying on white sharks! Scientists analyzed bite wounds on a white shark carcass and found killer whale DNA, confirming this apex predator battle.
Why does this matter? The absence of great whites in certain areas due to orca predation could change entire marine ecosystems! 🌊 Discover how this interaction reshapes the ocean food chain, why orcas target shark livers, and what it means for conservation.
Link to article: https://onlinelibrary.wiley.com/doi/10.1002/ece3.70786
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Transcript
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About a decade ago, great white sharks
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were popping up in South Africa on
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beaches without their livers.
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They were dead and they were just lying
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there, just carcasses were gone,
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and people were like, "What
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is going on with these livers?"
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Later found out that there were two orcas
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named Port and Starbird
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that would come in every once in a while
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and kill said great whites.
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And these great whites
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are known to be massive.
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They're like 18 footers, 20 footers, and
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they were typical of that area.
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That's where air jaws started.
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They were revered for what they could do,
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and that's jump out of the water as
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they're attacking the seal.
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They were the apex predator of the area
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until these orcas came by.
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That fueled a lot of research to find out
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why these orcas are
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going after these livers,
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what's happening, and until recently, we
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haven't really seen DNA
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evidence of this happening.
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We haven't really seen that, hey, these
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shark bites are from orcas.
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We haven't really seen these bites on the
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sharks that are
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actually from orcas until now.
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There was a paper that was recently
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released that was published in Ecology
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and Evolution, a peer-reviewed journal
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article that actually says genetic
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evidence of killer whale predation on
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white sharks in Australia.
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Now, I've been talking about South Africa
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because Port and Starbird, the orcas that
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have been around that have actually been
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killing these great white
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sharks are in South Africa.
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Now, they actually have
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DNA evidence in Australia.
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We're going to talk about why this is so
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important on this episode of the How to
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Protect Yours podcast.
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Let's start the show.
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[Music]
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Hey, everybody. Welcome back to another
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exciting episode of the How
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to Protect the Ocean podcast.
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I'm your host, Andrew Loewen, and this is
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the podcast where you find out what's
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happening in the ocean, how you can speak
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up for the ocean, what you can do to live
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for a better ocean by taking action.
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On today's episode, we're going to be
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talking about just eating great whites.
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I know I've talked about this before, but
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now we actually have genetic evidence
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that shows there are some orcas that are
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eating great whites in Australia, not
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just South Africa, but in Australia.
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This is a pretty big deal because we've
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seen videos of orcas
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attacking sharks before.
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We know they're an apex predator.
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We know they go after other apex
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predators, but orcas truly are the apex
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predator of the ocean.
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They're smart.
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They hunt together.
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They're fast.
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They're enormous.
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And like I said before, they're smart and
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they're going to go
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after these great whites.
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But we haven't really seen genetic
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evidence of these great
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whites actually biting sharks.
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We know they go after the liver because
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the liver is so dense in nutrients that
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there's a reason why they go.
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Orgas have been known
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to attack bolamolas.
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They've been known to attack a lot of
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different sharks,
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blue sharks and so forth.
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But we didn't really know until recently
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and I mean recently by the past couple
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decades that orcas start going after gray
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white sharks or they have been going
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after gray white sharks.
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And we've seen it in South Africa.
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We've seen it in other places, but now
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we're seeing it in Australia.
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And so I thought this
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was pretty interesting.
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So it was kind of interesting to see the
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genetic analysis confirmed the presence
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of orca DNA within a bite room offering
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direct evidence of
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predation of these great whites.
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They also saw some I guess some scavenger
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sharks that were also had bite marks
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against the great white sharks.
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And that was a seven gill shark or a type
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of seven gill shark, which I
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thought was pretty interesting.
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Obviously, these were post death.
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And so these bites were just as the shark
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was dying and probably
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floating or in the water column.
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They come in and they grab their flesh
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and they leave as well.
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So now previous anecdotal reports and
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indirect observation suggested that orca
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predation could lead to behavioral
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changes in white sharks such
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as avoidance of a specific area.
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This study provides concrete evidence
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such that interactions happen and which
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may also have cascading effects in the
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marine ecosystems like
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Australia has some big great whites.
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We know this.
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This may or may not be the first
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predation on a great white.
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We don't know, but it could lead towards
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movement of these great
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whites to different areas.
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We saw this happen in South Africa.
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There's still a bit of scientific
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controversy in that whether it is due to
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the lack of prey that's in
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the area for the great whites.
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So they've actually moved areas or if
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it's the increase of predation by port
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and starboard and some South African
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areas where these great whites are
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actually just moving away and moving.
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I think it's more to the
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east of where they were before.
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We don't really know for sure, but we do
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know that they avoid the areas because
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there's something going on in that area.
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There is a good reason to believe that,
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hey, look, if these orcas are coming in
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and they're predating and they're getting
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better at doing it in South Africa, it
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would usually take two
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orcas to grab the liver.
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One would actually hold the great white
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while the other would rip the area where
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the liver would be and then actually take
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out the great white without really
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destroying the animal.
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I think killing it, but
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really ripping the animal apart.
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They'd be very precise bites.
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Then we heard from Dr.
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Allison Towner on the Beyond Jaws podcast
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that she has seen one orca actually take
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out a number of great
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whites within a few hours.
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So that this goes to show they're
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actually getting better and better at
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killing these great whites.
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And so the fact that we see some orca
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predation on great whites in Australia
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could mean that these great whites are in
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trouble from a population
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standpoint from these orcas.
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So now this predation event actually
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raises some interesting questions about
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the ecological balance
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between these two predators.
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It also highlights the importance of
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understanding predator prey interactions
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in designing conservation strategies for
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both species, particularly in regions
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where human activities and environmental
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pressures are increasing.
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So just think about it.
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If you have a great whites, which we're
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at one point and endangered species,
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they're starting to come back because of
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specific conservation strategies that
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would allow their prey to flourish.
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Like in California, we saw an increase in
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the great white population because there
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was an increase in
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the sea lion population.
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That was because of the
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Marine Mound Protection Act.
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Now, there was also an increase in the
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sea lion population, not only because of
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the Marine Mound Protection Act, but the
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Magnuson Stevens Act, which is a
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fisheries act that allowed for more
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protection on anchovies and sardines,
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which the sea lions would eat.
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So having those policies in place allowed
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not only the prey of the sea lions to
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flourish, but allowed the sea lions to
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flourish, which is the prey to the great
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whites, which allowed the
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great whites to flourish.
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Now there are so many great whites in
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Southern California.
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They're starting to move northward or
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they have moved northward into the San
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Francisco Bay area in the Monterey area.
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And now there's like large great white
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sharks in those areas, adult great white
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sharks, where the Southern California
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population are actually
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juvenile sharks in that area.
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So it's like a nursery habitat
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for those great white sharks.
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This all changes if you have orcas coming
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in and predating on great whites.
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It could shift the balance of specific
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prey of the great whites.
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So for instance, if there are seals in
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the area in Australia, what the great
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whites are eating, the net seal
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population could grow, which could affect
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their prey that would actually reduce
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their prey and the balance
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would be all shifted off.
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I don't know if this is happening.
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This is all assumptions.
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But this is what could happen when you
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have orcas come into an area and wreak
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havoc on an apex predator population.
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So we're going to see some really
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interesting research come out in the
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future from these two apex predators.
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The significance of the study is this is
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one of the first studies to provide
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genetic evidence of orca
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predation on great white sharks.
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While previous accounts were based on
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indirect observations, such as scars on
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sharks or even changes in their presence,
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this study is definitely
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proof of direct interaction.
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So this is one of the studies
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that says, hey, you know what?
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We actually have DNA evidence that orcas
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have bitten in these areas where they
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would normally bite in the girdle area
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where the liver is just behind.
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Also, these findings contribute to the
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understanding of predator hierarchy,
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competition and ecological impacts in
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marine systems, particularly in regions
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like South Africa
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where both species coexist.
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01:07:42,750 --> 01:07:44,125
There's going to be some really cool
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01:07:44,125 --> 01:07:45,750
things that are coming out of Australia
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01:07:45,750 --> 01:07:48,250
from this research, even South Africa, as
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we really try to understand that
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01:07:50,625 --> 01:07:53,000
relationship between orcas and great
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01:07:53,000 --> 01:07:54,708
whites as well as other
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01:07:54,708 --> 01:07:55,958
sharks that end up flourishing.
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01:07:56,500 --> 01:07:58,000
So, for instance, in South Africa, when
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01:07:58,000 --> 01:07:59,875
we saw the disappearance of great whites
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01:07:59,875 --> 01:08:02,500
in the Gansby area, we also saw an
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01:08:02,500 --> 01:08:05,000
increase in seven gill sharks in that
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01:08:05,000 --> 01:08:06,625
area because seven gill sharks used to be
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01:08:06,625 --> 01:08:09,083
a prey item of these great whites.
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01:08:09,125 --> 01:08:11,125
So it's going to be really interesting to
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see what comes out further. And I can't
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01:08:14,666 --> 01:08:17,125
wait to see what happens. I hope that the
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01:08:17,125 --> 01:08:18,458
balance exists, but this is
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01:08:18,458 --> 01:08:19,833
nature. This is what happens.
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01:08:19,833 --> 01:08:21,666
Now, previously, I said that this is
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01:08:21,666 --> 01:08:22,625
going to be interesting to see how this
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01:08:22,625 --> 01:08:24,125
plays out, especially with human
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01:08:24,125 --> 01:08:26,208
interactions or even environmental
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01:08:26,208 --> 01:08:27,666
pressures that are increasing.
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01:08:27,666 --> 01:08:29,791
So climate change is increasing. Coastal
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01:08:29,791 --> 01:08:32,291
development is increasing. We're seeing
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01:08:32,291 --> 01:08:33,791
fishing pressures increasing.
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01:08:34,333 --> 01:08:37,333
All these play a dynamic role, not only
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01:08:37,333 --> 01:08:39,333
as individual issues, but also as
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01:08:39,333 --> 01:08:41,333
cumulative issues. And when you manage a
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01:08:41,333 --> 01:08:43,125
population, a lot of populations, fish
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01:08:43,125 --> 01:08:44,875
populations in general, they actually
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01:08:44,875 --> 01:08:47,541
have slowed in their recovery because of
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01:08:47,541 --> 01:08:49,083
outside pressures such as climate change.
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01:08:49,125 --> 01:08:53,000
We don't know how fast a fish population
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01:08:53,000 --> 01:08:55,333
can rebound off a change in population
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01:08:55,333 --> 01:08:57,625
dynamics or predator prey dynamics if
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01:08:57,625 --> 01:08:59,333
there's something else slowing it from
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01:08:59,333 --> 01:09:01,083
actually recovering or
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01:09:01,083 --> 01:09:02,625
actually the same area.
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01:09:02,625 --> 01:09:04,958
The cod population, for instance, in the
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01:09:04,958 --> 01:09:07,375
northeastern or northwestern Atlantic or
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01:09:07,375 --> 01:09:10,000
northeastern Canada, we have seen cod go
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01:09:10,000 --> 01:09:13,041
from so abundantly available that you can
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01:09:13,041 --> 01:09:15,083
just throw a bucket in like the 1800s and
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01:09:15,083 --> 01:09:16,791
you could actually just grab it with a
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01:09:16,791 --> 01:09:17,458
bucket and you'd grab
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01:09:17,458 --> 01:09:18,083
like two or three fish.
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01:09:18,083 --> 01:09:21,458
Now the cash per unit effort is so high,
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01:09:21,750 --> 01:09:23,708
meaning it's really hard to find cod and
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01:09:23,708 --> 01:09:24,916
there's so much protections on a call
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01:09:24,916 --> 01:09:27,041
that you just can't have a viable
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01:09:27,041 --> 01:09:28,625
commercial fishery like we
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01:09:28,625 --> 01:09:30,041
used to have in the past.
316
01:09:30,041 --> 01:09:31,875
But that was because we let fishing get
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01:09:31,875 --> 01:09:33,375
out of hand. We've been wanting that
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01:09:33,375 --> 01:09:35,416
population to recover and we've seen
319
01:09:35,416 --> 01:09:37,541
somewhat of a recovery, but it's taken
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01:09:37,541 --> 01:09:38,750
over 30 years for
321
01:09:38,750 --> 01:09:39,583
that recovery to happen.
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01:09:39,583 --> 01:09:42,333
And we're still not seeing it even close
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01:09:42,333 --> 01:09:45,041
to what it used to be in the 70s and 80s
324
01:09:45,041 --> 01:09:46,500
where they started to fall down as we
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01:09:46,500 --> 01:09:48,000
started to track those fish stocks.
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01:09:48,666 --> 01:09:50,083
So you just never know what's going to
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01:09:50,083 --> 01:09:51,875
happen. And a lot of times climate
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01:09:51,875 --> 01:09:54,041
change, more fishing pressures for other
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01:09:54,041 --> 01:09:56,291
fish that can affect the marine ecosystem
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01:09:56,291 --> 01:09:57,666
in the communities that these fish are
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01:09:57,666 --> 01:09:58,583
living in, that cod fish are living in.
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01:09:58,583 --> 01:10:01,166
You just never know what's going to
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01:10:01,166 --> 01:10:04,208
happen. So having the data, having more
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01:10:04,208 --> 01:10:07,041
research, understanding how each of these
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01:10:07,041 --> 01:10:08,708
issues like climate change, fishing,
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01:10:08,708 --> 01:10:10,333
coastal development, water pollution and
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01:10:10,333 --> 01:10:11,958
marine plastics, all these different
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01:10:11,958 --> 01:10:13,833
types of human issues that will cause a
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01:10:13,833 --> 01:10:15,375
disturbance individually and
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01:10:15,375 --> 01:10:17,708
accumulatively will play a role in the
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01:10:17,708 --> 01:10:20,333
recovery or the change in the population
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01:10:20,333 --> 01:10:21,833
dynamics and the predator prey
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01:10:21,833 --> 01:10:22,791
relationship between
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01:10:22,791 --> 01:10:24,541
orcas and gray whites.
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01:10:24,583 --> 01:10:25,500
It's going to be really interesting to
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01:10:25,500 --> 01:10:27,708
see how this happens. But of course, you
347
01:10:27,708 --> 01:10:29,416
can help by reducing your energy
348
01:10:29,416 --> 01:10:31,541
consumption. You can help by reducing
349
01:10:31,541 --> 01:10:33,791
your single use plastic usage. You can
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01:10:33,791 --> 01:10:35,791
help a lot of ways eating more
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01:10:35,791 --> 01:10:37,750
sustainable fish or avoiding fish
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01:10:37,750 --> 01:10:39,458
altogether or seafood altogether.
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01:10:39,583 --> 01:10:41,791
There are so many ways that you can help
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01:10:41,791 --> 01:10:43,500
individually. If you want to find out
355
01:10:43,500 --> 01:10:46,750
more, you can find out by staying in
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01:10:46,750 --> 01:10:48,416
touch with this podcast.
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01:10:48,416 --> 01:10:49,916
All you have to do is subscribe to the
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01:10:49,916 --> 01:10:51,708
YouTube channel and hit that notification
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01:10:51,708 --> 01:10:52,625
bell so you don't miss
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01:10:52,625 --> 01:10:53,583
any of the other episodes.
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01:10:53,625 --> 01:10:55,958
You can also hit me up on Spotify, on
362
01:10:55,958 --> 01:10:57,708
Apple Podcasts or your favorite podcast
363
01:10:57,708 --> 01:10:59,250
app. And if you want to get ahold of me
364
01:10:59,250 --> 01:11:01,958
directly, you can DM me on Instagram at
365
01:11:01,958 --> 01:11:03,708
how to protect the ocean. But thank you
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01:11:03,708 --> 01:11:05,500
so much for joining me on today's episode
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01:11:05,500 --> 01:11:07,083
of the how to protect the ocean podcast.
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01:11:07,291 --> 01:11:08,875
I had a great time talking to you today.
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01:11:09,208 --> 01:11:10,875
I hope you enjoyed listening. Have a
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01:11:10,875 --> 01:11:12,458
great day. I'm your host, Andrew Lewin.
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01:11:12,458 --> 01:11:12,958
We'll talk to you next
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01:11:12,958 --> 01:11:13,583
time and happy conservation.
01:00:00,625 --> 01:00:02,125
About a decade ago, great white sharks
2
01:00:02,125 --> 01:00:03,875
were popping up in South Africa on
3
01:00:03,875 --> 01:00:05,541
beaches without their livers.
4
01:00:05,541 --> 01:00:07,083
They were dead and they were just lying
5
01:00:07,083 --> 01:00:08,458
there, just carcasses were gone,
6
01:00:08,458 --> 01:00:09,250
and people were like, "What
7
01:00:09,250 --> 01:00:10,541
is going on with these livers?"
8
01:00:10,875 --> 01:00:12,916
Later found out that there were two orcas
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01:00:12,916 --> 01:00:14,000
named Port and Starbird
10
01:00:14,000 --> 01:00:15,458
that would come in every once in a while
11
01:00:15,458 --> 01:00:17,000
and kill said great whites.
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01:00:17,375 --> 01:00:18,083
And these great whites
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01:00:18,083 --> 01:00:19,375
are known to be massive.
14
01:00:19,625 --> 01:00:22,000
They're like 18 footers, 20 footers, and
15
01:00:22,000 --> 01:00:23,708
they were typical of that area.
16
01:00:23,708 --> 01:00:25,041
That's where air jaws started.
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01:00:25,250 --> 01:00:27,500
They were revered for what they could do,
18
01:00:27,500 --> 01:00:29,166
and that's jump out of the water as
19
01:00:29,166 --> 01:00:30,083
they're attacking the seal.
20
01:00:30,333 --> 01:00:33,041
They were the apex predator of the area
21
01:00:33,041 --> 01:00:35,291
until these orcas came by.
22
01:00:35,458 --> 01:00:37,291
That fueled a lot of research to find out
23
01:00:37,291 --> 01:00:38,458
why these orcas are
24
01:00:38,458 --> 01:00:39,500
going after these livers,
25
01:00:40,041 --> 01:00:42,250
what's happening, and until recently, we
26
01:00:42,250 --> 01:00:44,291
haven't really seen DNA
27
01:00:44,291 --> 01:00:46,375
evidence of this happening.
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01:00:46,583 --> 01:00:48,208
We haven't really seen that, hey, these
29
01:00:48,208 --> 01:00:49,833
shark bites are from orcas.
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01:00:50,125 --> 01:00:52,291
We haven't really seen these bites on the
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01:00:52,291 --> 01:00:53,041
sharks that are
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01:00:53,041 --> 01:00:54,875
actually from orcas until now.
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01:00:55,208 --> 01:00:56,541
There was a paper that was recently
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01:00:56,541 --> 01:00:58,166
released that was published in Ecology
35
01:00:58,166 --> 01:00:59,791
and Evolution, a peer-reviewed journal
36
01:00:59,791 --> 01:01:01,958
article that actually says genetic
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01:01:01,958 --> 01:01:04,125
evidence of killer whale predation on
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01:01:04,125 --> 01:01:05,750
white sharks in Australia.
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01:01:06,000 --> 01:01:07,833
Now, I've been talking about South Africa
40
01:01:07,833 --> 01:01:09,583
because Port and Starbird, the orcas that
41
01:01:09,583 --> 01:01:11,083
have been around that have actually been
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01:01:11,083 --> 01:01:12,291
killing these great white
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01:01:12,291 --> 01:01:13,458
sharks are in South Africa.
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01:01:13,666 --> 01:01:14,416
Now, they actually have
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01:01:14,416 --> 01:01:16,333
DNA evidence in Australia.
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01:01:16,791 --> 01:01:17,958
We're going to talk about why this is so
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01:01:17,958 --> 01:01:19,916
important on this episode of the How to
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01:01:19,916 --> 01:01:20,666
Protect Yours podcast.
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01:01:21,458 --> 01:01:22,291
Let's start the show.
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01:01:25,208 --> 01:01:28,458
[Music]
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01:01:29,000 --> 01:01:30,125
Hey, everybody. Welcome back to another
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01:01:30,125 --> 01:01:31,333
exciting episode of the How
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01:01:31,333 --> 01:01:32,333
to Protect the Ocean podcast.
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01:01:32,333 --> 01:01:33,458
I'm your host, Andrew Loewen, and this is
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01:01:33,458 --> 01:01:34,541
the podcast where you find out what's
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01:01:34,541 --> 01:01:36,375
happening in the ocean, how you can speak
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01:01:36,375 --> 01:01:37,791
up for the ocean, what you can do to live
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01:01:37,791 --> 01:01:40,291
for a better ocean by taking action.
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01:01:40,791 --> 01:01:41,708
On today's episode, we're going to be
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01:01:41,708 --> 01:01:43,833
talking about just eating great whites.
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01:01:43,833 --> 01:01:45,208
I know I've talked about this before, but
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01:01:45,208 --> 01:01:47,000
now we actually have genetic evidence
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01:01:47,000 --> 01:01:48,875
that shows there are some orcas that are
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01:01:48,875 --> 01:01:50,666
eating great whites in Australia, not
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01:01:50,666 --> 01:01:52,916
just South Africa, but in Australia.
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01:01:53,250 --> 01:01:56,000
This is a pretty big deal because we've
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01:01:56,000 --> 01:01:57,958
seen videos of orcas
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01:01:57,958 --> 01:01:59,208
attacking sharks before.
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01:01:59,750 --> 01:02:01,250
We know they're an apex predator.
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01:02:01,250 --> 01:02:02,583
We know they go after other apex
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01:02:02,583 --> 01:02:05,791
predators, but orcas truly are the apex
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predator of the ocean.
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They're smart.
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They hunt together.
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They're fast.
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They're enormous.
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And like I said before, they're smart and
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01:02:13,333 --> 01:02:13,916
they're going to go
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01:02:13,916 --> 01:02:15,000
after these great whites.
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01:02:15,208 --> 01:02:16,458
But we haven't really seen genetic
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01:02:16,458 --> 01:02:17,625
evidence of these great
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01:02:17,625 --> 01:02:19,583
whites actually biting sharks.
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01:02:19,625 --> 01:02:21,166
We know they go after the liver because
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01:02:21,166 --> 01:02:24,416
the liver is so dense in nutrients that
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01:02:24,416 --> 01:02:25,625
there's a reason why they go.
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Orgas have been known
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to attack bolamolas.
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They've been known to attack a lot of
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01:02:30,833 --> 01:02:31,666
different sharks,
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01:02:31,666 --> 01:02:33,125
blue sharks and so forth.
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But we didn't really know until recently
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and I mean recently by the past couple
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01:02:37,541 --> 01:02:40,125
decades that orcas start going after gray
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01:02:40,125 --> 01:02:41,583
white sharks or they have been going
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01:02:41,583 --> 01:02:42,541
after gray white sharks.
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01:02:42,541 --> 01:02:44,250
And we've seen it in South Africa.
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We've seen it in other places, but now
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we're seeing it in Australia.
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01:02:47,500 --> 01:02:48,458
And so I thought this
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01:02:48,458 --> 01:02:49,583
was pretty interesting.
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01:02:49,958 --> 01:02:51,125
So it was kind of interesting to see the
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01:02:51,125 --> 01:02:52,875
genetic analysis confirmed the presence
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01:02:52,875 --> 01:02:56,208
of orca DNA within a bite room offering
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direct evidence of
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01:02:57,541 --> 01:02:59,291
predation of these great whites.
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They also saw some I guess some scavenger
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01:03:01,708 --> 01:03:03,875
sharks that were also had bite marks
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against the great white sharks.
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And that was a seven gill shark or a type
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01:03:07,916 --> 01:03:09,041
of seven gill shark, which I
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01:03:09,041 --> 01:03:10,125
thought was pretty interesting.
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Obviously, these were post death.
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And so these bites were just as the shark
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01:03:14,125 --> 01:03:14,958
was dying and probably
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01:03:14,958 --> 01:03:16,291
floating or in the water column.
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They come in and they grab their flesh
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01:03:18,375 --> 01:03:19,458
and they leave as well.
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So now previous anecdotal reports and
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01:03:21,875 --> 01:03:23,958
indirect observation suggested that orca
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01:03:23,958 --> 01:03:26,333
predation could lead to behavioral
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01:03:26,333 --> 01:03:28,375
changes in white sharks such
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01:03:28,375 --> 01:03:30,250
as avoidance of a specific area.
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01:03:30,458 --> 01:03:32,208
This study provides concrete evidence
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01:03:32,208 --> 01:03:34,375
such that interactions happen and which
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01:03:34,375 --> 01:03:36,750
may also have cascading effects in the
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01:03:36,750 --> 01:03:37,500
marine ecosystems like
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Australia has some big great whites.
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01:03:38,750 --> 01:03:39,500
We know this.
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01:03:39,833 --> 01:03:41,541
This may or may not be the first
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01:03:41,541 --> 01:03:43,500
predation on a great white.
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01:03:43,500 --> 01:03:46,166
We don't know, but it could lead towards
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01:03:46,166 --> 01:03:47,708
movement of these great
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01:03:47,708 --> 01:03:48,875
whites to different areas.
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01:03:48,875 --> 01:03:50,750
We saw this happen in South Africa.
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01:03:50,750 --> 01:03:51,958
There's still a bit of scientific
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01:03:51,958 --> 01:03:54,666
controversy in that whether it is due to
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01:03:54,666 --> 01:03:56,375
the lack of prey that's in
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01:03:56,375 --> 01:03:57,375
the area for the great whites.
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01:03:57,375 --> 01:03:59,166
So they've actually moved areas or if
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01:03:59,166 --> 01:04:01,750
it's the increase of predation by port
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and starboard and some South African
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01:04:03,208 --> 01:04:04,791
areas where these great whites are
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01:04:04,791 --> 01:04:06,916
actually just moving away and moving.
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01:04:07,208 --> 01:04:08,125
I think it's more to the
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01:04:08,125 --> 01:04:09,833
east of where they were before.
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01:04:10,166 --> 01:04:13,125
We don't really know for sure, but we do
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01:04:13,125 --> 01:04:15,875
know that they avoid the areas because
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01:04:15,875 --> 01:04:17,833
there's something going on in that area.
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01:04:18,250 --> 01:04:20,750
There is a good reason to believe that,
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01:04:20,750 --> 01:04:22,750
hey, look, if these orcas are coming in
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01:04:22,750 --> 01:04:24,125
and they're predating and they're getting
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01:04:24,125 --> 01:04:26,000
better at doing it in South Africa, it
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01:04:26,000 --> 01:04:27,125
would usually take two
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01:04:27,125 --> 01:04:28,583
orcas to grab the liver.
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01:04:28,833 --> 01:04:30,375
One would actually hold the great white
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01:04:30,375 --> 01:04:32,666
while the other would rip the area where
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01:04:32,666 --> 01:04:34,458
the liver would be and then actually take
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01:04:34,458 --> 01:04:35,750
out the great white without really
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01:04:35,750 --> 01:04:37,041
destroying the animal.
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01:04:37,291 --> 01:04:38,083
I think killing it, but
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01:04:38,083 --> 01:04:39,583
really ripping the animal apart.
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They'd be very precise bites.
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01:04:41,916 --> 01:04:43,500
Then we heard from Dr.
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01:04:43,500 --> 01:04:45,166
Allison Towner on the Beyond Jaws podcast
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01:04:45,166 --> 01:04:48,041
that she has seen one orca actually take
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01:04:48,041 --> 01:04:48,958
out a number of great
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whites within a few hours.
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So that this goes to show they're
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actually getting better and better at
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killing these great whites.
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And so the fact that we see some orca
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predation on great whites in Australia
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could mean that these great whites are in
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trouble from a population
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standpoint from these orcas.
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So now this predation event actually
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raises some interesting questions about
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the ecological balance
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between these two predators.
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It also highlights the importance of
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understanding predator prey interactions
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in designing conservation strategies for
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01:05:19,083 --> 01:05:20,958
both species, particularly in regions
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where human activities and environmental
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pressures are increasing.
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So just think about it.
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If you have a great whites, which we're
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at one point and endangered species,
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01:05:28,708 --> 01:05:30,958
they're starting to come back because of
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specific conservation strategies that
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01:05:33,166 --> 01:05:35,333
would allow their prey to flourish.
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Like in California, we saw an increase in
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01:05:38,208 --> 01:05:40,500
the great white population because there
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was an increase in
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01:05:41,250 --> 01:05:42,166
the sea lion population.
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That was because of the
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Marine Mound Protection Act.
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Now, there was also an increase in the
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01:05:47,041 --> 01:05:48,500
sea lion population, not only because of
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01:05:48,500 --> 01:05:49,625
the Marine Mound Protection Act, but the
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Magnuson Stevens Act, which is a
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01:05:51,000 --> 01:05:52,750
fisheries act that allowed for more
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01:05:52,750 --> 01:05:55,500
protection on anchovies and sardines,
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which the sea lions would eat.
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01:05:57,500 --> 01:06:00,208
So having those policies in place allowed
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01:06:00,208 --> 01:06:02,416
not only the prey of the sea lions to
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01:06:02,416 --> 01:06:04,083
flourish, but allowed the sea lions to
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01:06:04,083 --> 01:06:05,666
flourish, which is the prey to the great
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01:06:05,666 --> 01:06:06,500
whites, which allowed the
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great whites to flourish.
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Now there are so many great whites in
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Southern California.
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They're starting to move northward or
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01:06:11,541 --> 01:06:13,208
they have moved northward into the San
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Francisco Bay area in the Monterey area.
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01:06:15,583 --> 01:06:17,375
And now there's like large great white
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01:06:17,375 --> 01:06:19,333
sharks in those areas, adult great white
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01:06:19,333 --> 01:06:20,791
sharks, where the Southern California
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01:06:20,791 --> 01:06:22,375
population are actually
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01:06:22,375 --> 01:06:24,041
juvenile sharks in that area.
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01:06:24,041 --> 01:06:25,416
So it's like a nursery habitat
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01:06:25,416 --> 01:06:26,875
for those great white sharks.
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This all changes if you have orcas coming
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01:06:29,958 --> 01:06:31,083
in and predating on great whites.
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01:06:31,083 --> 01:06:34,750
It could shift the balance of specific
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01:06:34,750 --> 01:06:36,416
prey of the great whites.
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01:06:36,916 --> 01:06:38,583
So for instance, if there are seals in
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01:06:38,583 --> 01:06:40,000
the area in Australia, what the great
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01:06:40,000 --> 01:06:41,500
whites are eating, the net seal
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01:06:41,500 --> 01:06:43,958
population could grow, which could affect
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01:06:43,958 --> 01:06:46,125
their prey that would actually reduce
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01:06:46,125 --> 01:06:47,375
their prey and the balance
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01:06:47,375 --> 01:06:48,666
would be all shifted off.
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01:06:49,041 --> 01:06:50,333
I don't know if this is happening.
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This is all assumptions.
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01:06:51,833 --> 01:06:53,666
But this is what could happen when you
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01:06:53,666 --> 01:06:56,541
have orcas come into an area and wreak
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01:06:56,541 --> 01:06:59,208
havoc on an apex predator population.
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01:06:59,625 --> 01:07:00,666
So we're going to see some really
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01:07:00,666 --> 01:07:02,041
interesting research come out in the
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01:07:02,041 --> 01:07:04,625
future from these two apex predators.
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01:07:04,875 --> 01:07:06,125
The significance of the study is this is
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01:07:06,125 --> 01:07:07,750
one of the first studies to provide
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01:07:07,750 --> 01:07:09,541
genetic evidence of orca
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01:07:09,541 --> 01:07:11,291
predation on great white sharks.
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01:07:11,750 --> 01:07:13,500
While previous accounts were based on
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01:07:13,500 --> 01:07:16,000
indirect observations, such as scars on
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01:07:16,000 --> 01:07:18,041
sharks or even changes in their presence,
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01:07:18,458 --> 01:07:19,625
this study is definitely
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01:07:19,625 --> 01:07:21,083
proof of direct interaction.
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01:07:21,125 --> 01:07:22,666
So this is one of the studies
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01:07:22,666 --> 01:07:23,791
that says, hey, you know what?
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01:07:24,000 --> 01:07:25,958
We actually have DNA evidence that orcas
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01:07:25,958 --> 01:07:27,708
have bitten in these areas where they
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01:07:27,708 --> 01:07:29,541
would normally bite in the girdle area
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01:07:29,541 --> 01:07:31,208
where the liver is just behind.
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01:07:31,875 --> 01:07:33,125
Also, these findings contribute to the
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01:07:33,125 --> 01:07:34,916
understanding of predator hierarchy,
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01:07:35,291 --> 01:07:37,666
competition and ecological impacts in
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01:07:37,666 --> 01:07:39,333
marine systems, particularly in regions
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01:07:39,333 --> 01:07:40,208
like South Africa
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01:07:40,208 --> 01:07:42,166
where both species coexist.
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01:07:42,750 --> 01:07:44,125
There's going to be some really cool
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01:07:44,125 --> 01:07:45,750
things that are coming out of Australia
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01:07:45,750 --> 01:07:48,250
from this research, even South Africa, as
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01:07:48,250 --> 01:07:50,625
we really try to understand that
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01:07:50,625 --> 01:07:53,000
relationship between orcas and great
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01:07:53,000 --> 01:07:54,708
whites as well as other
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01:07:54,708 --> 01:07:55,958
sharks that end up flourishing.
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01:07:56,500 --> 01:07:58,000
So, for instance, in South Africa, when
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01:07:58,000 --> 01:07:59,875
we saw the disappearance of great whites
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01:07:59,875 --> 01:08:02,500
in the Gansby area, we also saw an
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01:08:02,500 --> 01:08:05,000
increase in seven gill sharks in that
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01:08:05,000 --> 01:08:06,625
area because seven gill sharks used to be
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01:08:06,625 --> 01:08:09,083
a prey item of these great whites.
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01:08:09,125 --> 01:08:11,125
So it's going to be really interesting to
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01:08:11,125 --> 01:08:14,666
see what comes out further. And I can't
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01:08:14,666 --> 01:08:17,125
wait to see what happens. I hope that the
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01:08:17,125 --> 01:08:18,458
balance exists, but this is
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01:08:18,458 --> 01:08:19,833
nature. This is what happens.
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01:08:19,833 --> 01:08:21,666
Now, previously, I said that this is
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01:08:21,666 --> 01:08:22,625
going to be interesting to see how this
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01:08:22,625 --> 01:08:24,125
plays out, especially with human
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01:08:24,125 --> 01:08:26,208
interactions or even environmental
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01:08:26,208 --> 01:08:27,666
pressures that are increasing.
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01:08:27,666 --> 01:08:29,791
So climate change is increasing. Coastal
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01:08:29,791 --> 01:08:32,291
development is increasing. We're seeing
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01:08:32,291 --> 01:08:33,791
fishing pressures increasing.
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01:08:34,333 --> 01:08:37,333
All these play a dynamic role, not only
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01:08:37,333 --> 01:08:39,333
as individual issues, but also as
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01:08:39,333 --> 01:08:41,333
cumulative issues. And when you manage a
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01:08:41,333 --> 01:08:43,125
population, a lot of populations, fish
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01:08:43,125 --> 01:08:44,875
populations in general, they actually
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01:08:44,875 --> 01:08:47,541
have slowed in their recovery because of
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01:08:47,541 --> 01:08:49,083
outside pressures such as climate change.
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01:08:49,125 --> 01:08:53,000
We don't know how fast a fish population
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01:08:53,000 --> 01:08:55,333
can rebound off a change in population
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01:08:55,333 --> 01:08:57,625
dynamics or predator prey dynamics if
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01:08:57,625 --> 01:08:59,333
there's something else slowing it from
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01:08:59,333 --> 01:09:01,083
actually recovering or
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01:09:01,083 --> 01:09:02,625
actually the same area.
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01:09:02,625 --> 01:09:04,958
The cod population, for instance, in the
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01:09:04,958 --> 01:09:07,375
northeastern or northwestern Atlantic or
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01:09:07,375 --> 01:09:10,000
northeastern Canada, we have seen cod go
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01:09:10,000 --> 01:09:13,041
from so abundantly available that you can
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01:09:13,041 --> 01:09:15,083
just throw a bucket in like the 1800s and
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01:09:15,083 --> 01:09:16,791
you could actually just grab it with a
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01:09:16,791 --> 01:09:17,458
bucket and you'd grab
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01:09:17,458 --> 01:09:18,083
like two or three fish.
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01:09:18,083 --> 01:09:21,458
Now the cash per unit effort is so high,
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01:09:21,750 --> 01:09:23,708
meaning it's really hard to find cod and
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01:09:23,708 --> 01:09:24,916
there's so much protections on a call
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01:09:24,916 --> 01:09:27,041
that you just can't have a viable
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01:09:27,041 --> 01:09:28,625
commercial fishery like we
315
01:09:28,625 --> 01:09:30,041
used to have in the past.
316
01:09:30,041 --> 01:09:31,875
But that was because we let fishing get
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01:09:31,875 --> 01:09:33,375
out of hand. We've been wanting that
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01:09:33,375 --> 01:09:35,416
population to recover and we've seen
319
01:09:35,416 --> 01:09:37,541
somewhat of a recovery, but it's taken
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01:09:37,541 --> 01:09:38,750
over 30 years for
321
01:09:38,750 --> 01:09:39,583
that recovery to happen.
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01:09:39,583 --> 01:09:42,333
And we're still not seeing it even close
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01:09:42,333 --> 01:09:45,041
to what it used to be in the 70s and 80s
324
01:09:45,041 --> 01:09:46,500
where they started to fall down as we
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01:09:46,500 --> 01:09:48,000
started to track those fish stocks.
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01:09:48,666 --> 01:09:50,083
So you just never know what's going to
327
01:09:50,083 --> 01:09:51,875
happen. And a lot of times climate
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01:09:51,875 --> 01:09:54,041
change, more fishing pressures for other
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01:09:54,041 --> 01:09:56,291
fish that can affect the marine ecosystem
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01:09:56,291 --> 01:09:57,666
in the communities that these fish are
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01:09:57,666 --> 01:09:58,583
living in, that cod fish are living in.
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01:09:58,583 --> 01:10:01,166
You just never know what's going to
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01:10:01,166 --> 01:10:04,208
happen. So having the data, having more
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01:10:04,208 --> 01:10:07,041
research, understanding how each of these
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01:10:07,041 --> 01:10:08,708
issues like climate change, fishing,
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01:10:08,708 --> 01:10:10,333
coastal development, water pollution and
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01:10:10,333 --> 01:10:11,958
marine plastics, all these different
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01:10:11,958 --> 01:10:13,833
types of human issues that will cause a
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01:10:13,833 --> 01:10:15,375
disturbance individually and
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01:10:15,375 --> 01:10:17,708
accumulatively will play a role in the
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01:10:17,708 --> 01:10:20,333
recovery or the change in the population
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01:10:20,333 --> 01:10:21,833
dynamics and the predator prey
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01:10:21,833 --> 01:10:22,791
relationship between
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01:10:22,791 --> 01:10:24,541
orcas and gray whites.
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01:10:24,583 --> 01:10:25,500
It's going to be really interesting to
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01:10:25,500 --> 01:10:27,708
see how this happens. But of course, you
347
01:10:27,708 --> 01:10:29,416
can help by reducing your energy
348
01:10:29,416 --> 01:10:31,541
consumption. You can help by reducing
349
01:10:31,541 --> 01:10:33,791
your single use plastic usage. You can
350
01:10:33,791 --> 01:10:35,791
help a lot of ways eating more
351
01:10:35,791 --> 01:10:37,750
sustainable fish or avoiding fish
352
01:10:37,750 --> 01:10:39,458
altogether or seafood altogether.
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01:10:39,583 --> 01:10:41,791
There are so many ways that you can help
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01:10:41,791 --> 01:10:43,500
individually. If you want to find out
355
01:10:43,500 --> 01:10:46,750
more, you can find out by staying in
356
01:10:46,750 --> 01:10:48,416
touch with this podcast.
357
01:10:48,416 --> 01:10:49,916
All you have to do is subscribe to the
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01:10:49,916 --> 01:10:51,708
YouTube channel and hit that notification
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01:10:51,708 --> 01:10:52,625
bell so you don't miss
360
01:10:52,625 --> 01:10:53,583
any of the other episodes.
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01:10:53,625 --> 01:10:55,958
You can also hit me up on Spotify, on
362
01:10:55,958 --> 01:10:57,708
Apple Podcasts or your favorite podcast
363
01:10:57,708 --> 01:10:59,250
app. And if you want to get ahold of me
364
01:10:59,250 --> 01:11:01,958
directly, you can DM me on Instagram at
365
01:11:01,958 --> 01:11:03,708
how to protect the ocean. But thank you
366
01:11:03,708 --> 01:11:05,500
so much for joining me on today's episode
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01:11:05,500 --> 01:11:07,083
of the how to protect the ocean podcast.
368
01:11:07,291 --> 01:11:08,875
I had a great time talking to you today.
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01:11:09,208 --> 01:11:10,875
I hope you enjoyed listening. Have a
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01:11:10,875 --> 01:11:12,458
great day. I'm your host, Andrew Lewin.
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01:11:12,458 --> 01:11:12,958
We'll talk to you next
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01:11:12,958 --> 01:11:13,583
time and happy conservation.
