Marine biologist and shark expert Luke Tipple recalls his first shark interaction and the importance of sharks to oceans and planet earth.
In this episode of Shark Week: The Podcast, marine biologist and shark expert, Luke Tipple recalls his first shark interaction as a child spear fishing with his father and how that was the moment that sparked a life-long passion to study and protect sharks. He breaks down the critical role of sharks in keeping healthy ecosystems in all earth’s oceans and why our way of life would suffer greatly if sharks were no longer with us. He details the unique places sharks call home and describes shark species' diverse needs in habitats -- from warm, tropical ocean waters to deep, icy ocean waters.
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[00:00:00] Luke: Good day and welcome to Shark Week: The Podcast. I'm Luke Tipple, marine biologist, and a frequent voice on my favorite things, oceans and sharks. I'm stoked to bring the magic of shark week, right to your ears.
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[00:00:16] Luke: Sharks have been a big part of my life for over 20 years now, studying them and diving with them all around the world. I guess that's given me some of the street cred to participate in many shark week documentaries throughout the years, and now to be your host. So whether you've never seen shark week before, or you've been a diehard fan over the 30 plus years, it's been around this podcast is for you.
[00:00:42] Today. I'm really excited to be focusing on the shark's habitat and their role in the environment. And this is of particular importance to me because, quite honestly, it's one of the questions people ask the most. You know, in my career, I've spoken to a lot of people and people have just endless questions about sharks, but one that always comes up is why should I care?
[00:01:02] Why should you care about sharks? I'm asking you at home. Why should you care about sharks? You might live nowhere near the ocean. You might go out on the river occasionally or the lake, you might never have seen the ocean. What do you care about sharks? The reality is your lifestyle, the one that you enjoy, relies on large predators, like sharks, being in environments to keep them clean, to keep them tidy, to do their job.
[00:01:29] And this goes for the ocean, for land and everything else. But we are here to talk about sharks. I'm gonna tell you why sharks are important to you. I've seen a lot of different places that I've gone to find sharks. And this is everything from coral reefs to, you know, brackish swamps. But it always, for me, comes back to the times when I fell in love with sharks.
[00:01:48] And this is, you know, me spear fishing on a reef when I've come across a great white shark, you know, as a 12 year old stuffing whiting down the front of my wetsuit, that I was spearing with a little three-pronged fish and wondering why I suddenly had those little feelings on the back of my neck of what's happening.
[00:02:07] I turn around in what seems like slow motion, like a really bad stop motion, horror film, and there coming out of the deep darkness, which really isn't darkness, but to my brain, it seems like darkness. There's this massive monster, great white shark coming straight at me. But more on that in a moment, we have to come back to that question about why they're important to you.
[00:02:32] And I think in doing so, we have to address, kind of the elephant in the room, which is the instinct that you probably had when I keep saying the word shark. For a lot of people, that's fear. And that's okay. That's totally okay to feel because we've been trained to feel that way. The media has told us all these horrible things about these animals without explaining all the amazing things they do for us.
[00:02:57] And we've been trained to have a fear response to this animal. You know, one of the things that absolutely intrigues me in my work is that I get to travel to a lot of different places to find sharks. And when I say different places, I'm not just saying, you know, cool countries around the place that all have pretty colorful reefs around them.
[00:03:16] I'm saying different places where one might be a super life-abundant coral reef. Another one might be a really brackish, you know, dark water, murky, swampy kind of place. And we're finding sharks in all of these. And we've talked about how abundant sharks are that they exist in every single place, every single ocean, every single ocean connected body of water that there is.
[00:03:42] What I'd like to get into is the different types of specialties and different types of environments they go to because sharks do inhabit all five of the world's oceans. For those who don't know, that's the Atlantic, the Pacific, the Indian, the Arctic, and also the Southern ocean. Now that fifth one is kind of a weird one ‘cause most countries recognize it as an ocean, some countries don't, it's part of my heritage so I say, it's an ocean!
[00:04:07] Sharks are not at all territorial. They don't hang out on one little reef and protect their spot and that's where they feed and they'll shoo anything else away. That's simply not true, but they do have their happy places. They like a certain mix of water or a certain temperature of water or depth of water.
[00:04:25] And they'll travel throughout that environment to find the food that they're after. So, we'll find fish that'll migrate heavily and sharks will follow them. And that'll usually be to follow different types of water currents and temperatures. Of note these days, is we're starting to learn this kind of mind blowing stuff about sharks and other animals is that they are now moving into places where traditionally they weren't before.
[00:04:50] And we'll see more and more of this, definitely in Shark Week, but probably in the media, as well as we hear about, you know, upper, New England and suddenly there's sharks there that weren't there before. It's because the water is warming and we're seeing things like the Blob if you've ever heard of the Blob, where it's this great, big, massive warming water in the Pacific ocean, we've known about it for almost 10 years now.
[00:05:14] As that's moving, we're seeing the traditional habitats of some of these, especially larger open ocean sharks. It'll change a bit. So it's pushing them around. So this is kind of emerging science that we will not really understand the full ramifications of for quite some time, but let's get into the actual area.
[00:05:32] So you've got an understanding of how a shark thinks. So, first off, let's start with the biggest area. This is what we call the pelagic zone or the open ocean. This is some 300 million cubic miles of water. Now, pelagic sharks or oceanic sharks, these migratory ones, they're constantly on the move. Hunting, looking for food.
[00:05:52] These are sharks like the blue shark, the whale shark, which travels for warm water and plankton abundance. The oceanic white tip is another famous one. Other animals like the short fin mako, you know, these sharks have been tracked, moving for thousands of miles every year. In fact, there's one whale shark that I have a particular fondness for.
[00:06:12] They called her Ann. She was tagged and tracked for 841 days. And she traveled from the coast of Panama to the Marianas trench, which is south of Japan. And she went about 12,500 miles over that period of time, which is just an insanely long distance for these sharks to travel, but she's moving with the water, she's going where the food goes.
[00:06:34] As an example of sharks that don't travel so much, we need to look into the deep ocean. Now the deep ocean is ocean that's, you know, a thousand or 2000 meters deep, you know, beyond 3000 feet. These are often fairly small sharks, with the odd exception, but they're often fairly small. They have big eyes, they look kind of like aliens.
[00:06:53] And, we only ever really see them when they're hauled up from a, you know, perhaps a deep sea trawler or something like that. It often makes the news because they look weird and super cool. They're not at all a threat to humans, but they do some important work on the bottom of the ocean as scavengers and predators.
[00:07:08] To give you an idea about how deep that is, the deepest recorded shark was a Portuguese Dogfish that was recorded at about 12,000 feet deep. It's about 2.3, 2.4 miles down, which is very very deep . My favorite place to be is on the coral reef. And this is where we'll find about 25% of the planet's sea life.
[00:07:32] Reef sharks in this area and also pelagic sharks who come across, but, you know, reef sharks who call the reefs their home are incredibly important in keeping the reefs healthy, vibrant, colorful and full of life. Now we're gonna dive into this a little bit later, but it's kind of this paradox where you need the predators to keep all of the other animals in check.
[00:07:55] So, an abundance of life requires predators and really that goes for any kind of environment, but especially with coral reefs. So the heroes of this environment are the black tip reef sharks, the Caribbean reef sharks that we see so much of. Little sharks, like the zebra shark that are super cute, but do a really important job.
[00:08:14] And the gray reef shark, which is, you know, one of my favorites. The shallow regions are an interesting part. These are ones that are like really close to shore. And we think about them, as scientists, as parts of the water that are just on the edge of the continental shelf. So we see a lot of Marine life. We see a lot of overlap with coral reefs and other environments like that, but here's where we'll find sharks are kind of unusual looking.
[00:08:39] They're not quite deep sea, but they're still kind of gnarly and cool looking like the angel shark, which is almost like a kind of flat ray-looking shark or one of my favorites as a child, the wobbegong shark, you know, that was one of the first sharks I ever saw was a wobbegong shark. In Australia, we call 'em carpet sharks because the front of their face has this kinda weird beard looking thing.
[00:09:00] What they'll do is they'll sit on the bottom and blend into their environment and they'll dangle these protrusions out front of their face. And they'll just wait for fish to come along and see what that is. And then they'll snap 'em up. They’re gnarly little sharks. They can actually bite really hard. And there have been instances where someone's been waiting along in the water and whether they, you know, had a negative interaction with it, or quite often, you know, a spear Fishman has shot it for some reason.
[00:09:26] And the shark has clamped on them and they've been unable to get them off their leg without killing the animal to remove it. They've got such a tight jaw strength because they want to grab that fish as it comes past.
[00:09:49] Now, one of the really interesting places that people don't think about all that much is fresh water. We often associate, and it's totally fair to associate, sharks with the ocean, but estuaries and rivers that run into the ocean are also a place to find an abundance of sharks. And I'm not just talking about the hero of this environment, the bull shark, you know, if you didn't know, the bull shark can survive extremely well in fresh water, theoretically, they can live their entire life in fresh water if they wanted to.
[00:10:18] They've been known to travel up to 1700 miles up the Mississippi river. In fact, they've only stopped because they've got stopped by dams. They are born in fresh water as pups. As adults, they tend to move out into the ocean, but this is a shark that is actually able to retain salt in its body.
[00:10:36] And therefore, live for most of its life, if it wants to, in the fresh water. And that really just comes down to a bait abundance thing, but we'll also see estuaries and rivers used by many, many other sharks. Even sharks like lemon sharks will be way up in those estuaries, especially as pups, because it's a nice calm environment, free of larger predators, and they can feed on shrimp and lots of other small fish as they're juveniles, as they're growing up, before they move into the ocean and perhaps become prey for larger sharks out in that open environment.
[00:11:09] Now, as I've alluded to several times here now, sharks are just so critical in the environment and it's hard to place too much importance on that, to be honest. You know, as humans, we rely so much on the ocean for our food and our sustenance.
[00:11:26] And I think we're gonna come into a period of time, hopefully not right now. You know, when I say right now in the next 10 to 20 years, but I think within many of our listeners' lifetimes, we're gonna come into a period of time where we have largely depleted much of the ocean of its food sources. We're seeing massive depletions of, you know, food that we like to eat.
[00:11:50] You know, things like fish and crustaceans and a big part of that, as I've said, is keeping that ecosystem healthy and not removing these larger predators. You know, I think a big part of why people target sharks is obviously for their products, for their, you know, meat, fins and stuff. We'll get into that a little bit later, but it's also this weird kind of thing that humans have with targeting things that scare us.
[00:12:15] And, and it wasn't always that way. I don't think humans were always afraid of sharks. I think it's something that the media has perpetuated that, you know, movies have capitalized on and we've now got. Seed of fear of sharks in us. And, you know, it's substantiated, there are negative interactions with sharks, absolutely.
[00:12:34] But you know, they're fairly small and I don't wanna write them off, but in the grander scheme of things, there's a lot more dangerous things on the planet than sharks, but we just seem to just target them with this kind of malicious intent, but it wasn't always that way. You know, if we look back at more sort of tribal history of the human race, for example, in the Marshall Islands, the tribes had their own sacred sharks.
[00:12:58] And if someone disrespected another tribe's shark, they’d need to go and apologize to them. They'd go to war, literally go to war and fight over the disrespect that they've caused this other tribe’s shark, which I think is frankly amazing. The Hawaiians have famously worshiped sharks as their gods. In fact, they had nine shark gods with names.
[00:13:17] In Papa New Guinea, they believed that sharks were the embodiments of their ancestors. You know, the ancestors have died and moved on and become these almost mythical beings. The protectors of their reefs, which I think is beautiful. But there are some examples of more traditional cultures having their darker myths about them as well.
[00:13:36] Like, in the Solomon Islands, here's a kind of a gnarly one for the, you know, the late night crew. They believed that sharks could be appeased by a human sacrifice and they did cast victims, both living and dead, into areas of water where they knew sharks would be. So it hasn't always been a ray of sunshine with how we've thought of sharks, but it certainly was a lot more respectful.
[00:14:00] And I would love as a culture if we could kind of get back to that. Because, as I mentioned, sharks have such an important role. Let's analyze a trophic pyramid. So if you imagine a pyramid. Think about, you know, any type of food chart or something you've seen where you've got the little things at the top and the big things down the bottom.
[00:14:16] That's pretty much how the ocean works. Sharks are right at the tippy top, right at the very pinnacle of this pyramid and it's their job to keep the numbers of everything else in check. So for example, if you were to remove sharks from a healthy reef system, you'd trigger a cascade effect. And this has been shown in several islands in Indonesia, for example.
[00:14:38] Where, fishermen have traditionally removed sharks pretty regularly to, you know, feed the local food needs, but also the sharkfin market and these reefs that didn't have sharks around them anymore, they had other fish such as snapper and snapper would be kind of just the next level down from sharks.
[00:14:47] Now, snapper are abundant breeders and abundant eaters. So if they aren't kept in check, they have this voracious appetite where they'll go around and just snap up and eat all these other fish on the reef, which sounds okay. Right? Because you think, wow, there's gotta be lots of snapper to eat, but that's not actually what happens.
[00:15:18] The snappers eat. They breed more, they have more young, all of those need to eat. And because there's no sharks to eat up the snapper, the snapper end up removing all the other fish from the reef and the reef eventually suffers, and in some cases dies, because the job of the little fish, the ones right down the bottom, is not only to feed the fish above them, but to keep the reef systems clean. They eat all the algae and all the stuff that clings onto coral reefs to stop it from growing.
[00:15:47] So they're there basically to clean the reefs, to keep things healthy. And, without the sharks at the top, the guys in the middle take over and eventually the entire pyramid falls apart and the coral reef dies, lots and lots of fish move away. And we've lost that piece of reef for who knows how long it could be generations until it grows back.
[00:16:08] You know, I think it's pretty fair to say that the presence of sharks is absolutely required for a healthy environment, particularly on the coral reefs. And you can even think of it as sharks are a really good insurance policy for the reef's longevity and long term health. So to end this episode, I wanted to circle back on this thing that I, you know, just kind of dropped out there about me turning myself into this massive shark fishing lure as a kid.
[00:16:33] Now, first of all, don't turn yourself into a massive shark lure. It's not the smartest thing to do for sure. It’s definitely not the safest thing to do. And, I'm not recommending it, but it was part of my personal evolution and my understanding of sharks and, you know, my personal fascination with this animal and realizing how important they were to the ocean.
[00:16:58] So if you join me again, I’m 12 years old, spear fishing with a three-pronged spear in fairly shallow water, maybe eight feet deep. I'm swimming around shooting these whiting. These are just silver fish, very common in Australia. Great eating and I'm shooting probably 10 to 12 of them at a time. And what I used to do is grab them still wiggling off the front of my spear, stuff them down my wetsuit, and they'd all be flapping around and stuff.
[00:17:24] My wetsuit always spelled terrible. But I'd keep 'em down there because that's just an easy place to stuff them. And then, that feeling on the back of your neck, like something's watching me, something's watching me and then I'd turn around. And I remember it clearly. I've got this kind of like horror movie thought as I turn around and I see that body there and there's a great white shark in eight feet of water coming towards me.
[00:17:49] I take three or four quick hurried breaths, and I prepare to just bolt. And I really dunno what I'm doing at this point. And then I realized, okay, number one, that's not a great white shark. There's a bronze Whaler, which is not an unformidable species, but it's certainly not a great white shark, especially not in eight feet of water coming towards me, but it's a species I can probably manage at this point.
[00:18:11] And my only thought in my mind was give it something to eat instead of you. Right. you've got tons of food. So I grabbed one of these formally wrigging whiting out from my chest, threw it on the ground or into the water and keeping my eyes on it, backing away, swimming away rather quickly. And rather horridly, I can't say I was any type of consummate waterman with sharks at that point in time. But I realized that hey, all it wants is the food and it came after the food.
[00:18:39] It ate that. It performed its job as being a scavenger on the reef, which is exactly what those sharks are meant to do. And then I threw out another one. I got to the reef, I managed to climb up onto it and exit, as I watched this shark, keep on swimming and keep doing its thing. It wasn't coming after me.
[00:18:56] That was my own fear reaction. It was justified at the time, but my fascination started with understanding this animal even more. And I can credit that moment for probably a large part of my career moving.
[00:19:12] All right, that wraps up another episode of Shark Week: The Podcast. Stay tuned to this feed for shark facts you don't wanna miss and interviews with shark experts that will give us a behind the scenes scoop on what really happened out at sea. And… a lot happens in a month out at sea, and yes, we're keeping the shark passion alive after shark week is over, covering the Sharkiest current topics, talking to top scientists and experts to learn all about the latest conservation efforts in keeping this amazing animal from extinction.
[00:19:42] Thanks for listening to Shark Week: The Podcast. Be sure to rate us five stars and subscribe for more shark fun facts. I'm Luke Tipple. I'll see you next time.