Orcas vs Great White Sharks: How Killer Whales Are Changing Shark Populations

0:00 If orcas keep targeting young, great white sharks, could they actually reshape the future of one of the ocean's most iconic predators? New footage shows orcas hunting juvenile great white sharks in what scientists believes are nursery zones, the very places where this next generation is supposed to grow safely. If these attacks become more common, we're not just watching Predator versus predator. We might be witnessing a shift that could ripple through the entire marine ecosystem. We're gonna talk about all that on today's episode of the How to Protect the Ocean Podcast. Let's start the show. Hey everybody. Welcome back to another exciting episode of the How to Protect the Ocean Podcast. I'm your host, Andrew Lewin, and this is the podcast where you find out what's happening with the ocean, how you can speak up for the ocean, and what you can do to live for a better ocean by taking action.

0:44 Now, on today's episode, we're gonna be talking about how orcas in Mexico, in Mexican waters are actually hunting juvenile great white sharks. They're predating on a smaller species going after their livers, and we actually have video evidence of that happening that was published recently in Frontiers and Marine Science. We're gonna talk about that today. But before you do, I want to remind you if you saw last episode, you know that I launched a campaign to crowdfund the launch of a seagrass podcast called the Seagrass Effect. Seagrasses are a very important habitat for marine life. They have a high biodiversity index. They protect species from being predated on. They protect the security of the coastline. And they sequester carbon.

1:25 They're one of the biggest habitat to sequester carbon up to four times more than forests. And we are gonna be talking about that on the podcast called The Seagrass Effect. I just need your help in crowdfunding it because Speak up for Blue Network. How to protect the Ocean, Beyond Jaws is a crowdfunding network. This is a place where you can have your say in what you want to hear. And I think that's gonna be really important for us to get the word out on sea grasses. So we're gonna have research, we're gonna have conservation restoration efforts from all over around the world. Not only are we gonna be connecting that research with other scientists, but we're also going to be helping to restore sea grass habitat. You can support the podcast and help it launch by going to speak up for blue.com/seagrass where we're on a crowdfunding site for Ocean Projects called balean.org.

2:07 So speak up for blue.com/seagrass. Please help us out today and let me know if you do. I'd love to hear from you So let's get back into the episode. This looks like another population that is predating upon great white sharks. We've seen this before in South Africa. We've seen it potentially in other places, I think in sort of the northeast Pacific, like northwest of the United States. And we've seen it happen where orcas will in a pair One of them will grab a great white shark. The other one will precisely go after their liver, make an incision, pull out their liver. Eat their liver and then they kind of take turns in it depending on where these great white sharks are. We've followed port and Starbird, two orcas that had a pretty big impact on the great white shark population in South Africa, and it's a little controversial of whether that's the reason why there aren't as many great white sharks.

2:51 In specific bays like Mossel Bay and other places. There's a lot of other things at play at that, but they've definitely had an influence in where these great white sharks are or where they've disappeared to in South Africa. But now we're starting to see, and we have video evidence. Repeated predation of juvenile great whites by orcas in Mexican water. So the authors of this study that was in Frontiers in marine science report two attack events in the Gulf of California, August, 2020 and August, 2022, involving a pod of orcas on juvenile great white sharks around. 2.5 meters in length. So that's probably, around like the nine feet, maybe a little bit, maybe a little bit less than that rather than the adults that are going after these juvenile areas.

3:34 Now this adds a new dimension compared to previous observations, which mostly involve adult white sharks, which these orcas are getting better and better. Port starboard have been shown and observed to actually predate upon a great white by themselves. It's not in pairs anymore. It's by themselves going after, you know, 20 footers. These are big sharks now, these juveniles are smaller, as we mentioned before Now, of course in Mexican waters they're smaller animals, so you're probably seeing one orca on each animal. But they're starting to see this happen obviously on more than one occasion, which makes us believe like, Hey, how much is this happening in these nurseries areas? So this is really interesting. So. The orcas use a method of special behavior of flipping the young sharks upside down inducing tonic immobility. When you flip a shark upside down, it kind of paralyzes them, like temporarily immobilizes them.

4:18 And so when they flip them over, they get uninterrupted access to the shark's liver and perhaps other energy rich organs. But mostly we know they go for the liver, which they consume, and sometimes sharing it among the pod members including the calf. So it could be a way of teaching these calfs how to hunt or even how to like, get a taste for these livers. We know that orcas display interesting characteristics when they hunt. They will put salmon on top of their heads and ride around with salmon on top of their heads. We still don't know the reasons why we think it's more of like a celebration of a good hunt. We're not sure though completely. I know from anecdotal evidence of people that I've heard from. They'll eat moola molars and put the half the moola moola on their head. It's very interesting behavior, odd behavior, but interesting behavior nonetheless.

5:01 And so we know these sharks go after specialized organs. Sometimes brains, sometimes others parts. The tongue of blue whales, they like to go for when they're in Australia. And so it's a lot of just different things that happen, and the way they, they hunt and they're very specialized in that. But in this way, they flip the sharks over, they immobilize them, they get access to those organs, especially the liver. And then they share among the pod. This has been shown before where they actually will hunt to feed other members of their pod. It shows a level of intelligence and heightened awareness, and I think that's really interesting. Now, of course, the impact images of the dorsal fin markings and repeated behavior point to the same pod of orcas referred to as the Moctezuma a pod, being involved in both events so that they identify the actual pod, so it's the same pod every time.

5:44 The author suggests that this pod may have a specialization in hunting elasmobranchii sharks and rays in this region beyond typical orca prey. So this is not just like they'll go after marine mammals, they'll go after others. They actually try and go after elasmobranchii Stingrays. Flat sharks, what we like to call them, as well as other sharks like what you see, like great whites and so forth. So I think that's kind of interesting. And then of course, the presence of juvenile white sharks in this region may reflect shifts in the distribution, attributed in part to warming water anomalies such as El Nino events which could bring young sharks into zones where orcas operate regularly. So nursery areas for great white sharks are really still being discovered in specific areas. We know there's a nursery area in Southern California along the west coast of the United States, and of course now we're thinking that there's a nursery area.

6:26 We don't know the extent of it or if it stays in one area all the time. Just like I mentioned before, El Nino events and other event warming events may shift where these waters are, depending on their food availability for these nurseries. Obviously nursery areas are areas that are gonna be bound with food for these great whites so that they can grow and can go after food that's more their size, more their liking, and that'll be great. But if it comes in areas where there are orcas, which we know there are in the Gulf of California. Then that can actually have an impact on their population. So the authors, they raise concerns of how predator and prey dynamics may change if juveniles are more exposed, and how this might affect the recruitment of great white sharks in the future. They already have slow life history. So an impact like this where if orcas can go in and impact like adults in Southern Africa where you have those huge 20 footers, now you're looking at an area that we're smaller that are growing into and that will spread around the ocean and show like a population that's doing well now may be impacted.

7:20 They have slow life history, so if there's more animals that get impacted in terms of get eaten, they're not there for the next generation to grow, right? That generation to grow up into adults, which will impact their recruitment, it'll impact their reproductive ability. It'll have lower impact in the future. Hence, that's the concern that happens. And we just don't know if this is gonna happen all the time. We have no idea if this nursery area is gonna be in the same place next year or the year after, or if it's still in the same place this year. This happened in 2020 and 2022, which to be honest, is one of the problems with peer reviewed papers. Although, you wanna make sure everything is great, it's just the writeup, it doesn't happen quick enough. Hopefully they're still observing these areas and the more research will be done to see if this happens over and over again. Or if the nursery areas, these sharks are in the same space, they may have left because of that predation.

8:01 The ones that are better off surviving may have moved into another area based on prey, also just based on survivability. So we just don't know what's gonna happen to this population. Well, let's be honest, great White sharks have had a boom in population in the United States, on the East coast and on the west coast. We've seen a proliferation of sharks, even in their distribution, has changed as adults. We know the Southern California nursery area, but also adult sharks are going as high as San Francisco Bay, and he may be even higher. On the East coast, it used to be Cape Cod, now they're going up to the Gulf of St. Lawrence in that area in Nova Scotia. So where they're starting to see that move, north as the water's warm and they still within their range. They go out to the Mid-Atlantic bite, they go all the way down to Florida Cape Cod, and now even north into Canadian waters.

8:42 This is going to be a case where monitoring is still gonna be needed for not only these great whites, but also see what these orcas are eating and where they're going and how the nursery areas are going to change based on warming waters. You know, it's gonna be a lot of oceanography, iss gonna be a lot of ecology. And, see those, distributions warmer water. predator prey kind of relationships, like the prey for the juvenile. Great whites, are they gonna be in the same area? Are they gonna move because of the shift in warming waters? There's a lot to learn from this, but having these two events definitely shows a pattern that may have already been there, or maybe something new just because the orcas are like, Hey, we have new food. This is really rich in nutrients, and we like it, and, we're getting a taste for it. Now, of course, as they're getting a taste for it, will they follow these sharks along? Who knows.

9:22 Will the Sharks population be affected later on? We don't know at this point, but something that we definitely have to keep an eye on. So, looking at nursery areas, looking at warming, water distribution, looking at predator prey distribution and looking at orca distribution, obviously a predator, the apex predator, it seems very, very smart, and help feeding each other and, members of their pod I think is brilliant. So we're seeing a lot of really cool things that are happening out in the ocean, but also some scary things that can happen in the future. Now, obviously there's gaps. We still don't know how often these interactions occur, the frequency. So how widespread is this behavior among Orca pods and is that happening in elsewhere now that there are more great white sharks? Also it highlights the limitations of regarding how long juvenile white sharks stay in that particular region.

10:03 Their anti predator responses, where are they gonna go now, as I mentioned earlier and how changing ocean conditions might alter the nursery areas, and the predator overlap. So we'll see what happens. It's a call to action, definitely to have more systemic monitoring of shark nurseries, orca behavior, and shifting habitat overlap. So that's it for today's episode. I'd love to hear what you think about this. Do you think these orcas are gonna affect the great white population in the future? Do you think this is just like an anomaly? It just happened just because everything just kind of came to be for these orcas and the great white sharks, that those juveniles just kind of came in because they're following prey and that will change in the future. I'd love to hear what you have to say, and if you're involved in any of these studies, let me know. I'd love to have more questions for you, but that's it for today's episode. You have any questions or comments, just let me know in the comments below if you're watching this on YouTube.

10:45 If you're listening to this in your favorite podcast app, just hit me up on Instagram at how to protect the Ocean that's at How to protect the ocean. Of course, if you want to go to speak up for blue.com/contact, you can contact me. Just fill out the form. It goes right to my email. I'd love to hear from you. I wanna thank you so much for joining me on today's episode of the How to Protect the Ocean Podcast. I'm your host Andrew Lewin from the True Nord strong and free. Have a great day. We'll talk to you next time and happy conservation.