Do sharks matter?

Show notes

We all know that the majority of shark species are in decline. But what actually happens if they are lost from the ecosystem? How important are sharks? We pitch these questions to scientist, shark enthusiast and author Dr David Shiffman, who spends a lot of his time highlighting why sharks really do matter – not just in an ecological sense, but also from a social, economic and cultural perspective.

As always, we begin by talking about David’s most memorable ocean experience [05.53]. Consider this a warning – it’s a little gory (safety first, kids!). We also talk about his childhood, where he went through both a ‘shark phase’ and a ‘dinosaur phase’ (like most of us, I’d imagine!)[09.20]. He explains his formative decision to dedicate his life to sharks, although the fact that sharks are considered living fossils means he still stays connected with that early fascination for prehistoric critters. David then describes his journey from ‘8-year-old nerd’ to a fully-fledged shark scientist, including a very special encounter with the one and only Eugenie Clark [11.21].

We then start to address the question of ‘do sharks matter’ by talking about a very important species: the sandbar shark [16.18]. Sandbars are perhaps the most studied species in the world and have given us some important answers to questions about shark biology, ecology and behaviour. David has a soft spot for sandbars, having studied them for his Master’s degree, and continues to spread the love for this species on social media (if you tweet him using #bestshark, you’ll make his day!).

Next, we get into some of the potential ecological consequences of losing sharks [27.51]. The short answer is: it’s complicated. Marine food webs are so complex that it is difficult to ascertain the exact effects of a single species being removed. But we do know that sharks are an integral part of their ecosystems – being both predators and prey. As David says, just because we don’t know for certain, doesn’t mean we want to find out. David explains trophic cascades, the knock-on effects of a species being removed from its ecosystem, and some possible examples from the real world, including reef systems [28.23]. He also describes ‘fear ecology’ [31.11] – the theory that prey species may behave differently in the absence of a predator. We also discuss keystone species [38.31], which are animals that have a disproportionate effect on an ecosystem relative to their abundance (for example, a species that has a substantial impact on how an ecosystem operates, even if there is just one of them). Many sharks are considered keystone species, which means that their removal likely will result in dramatic changes to an ecosystem. We also take some fun detours to discuss tiger shark vomit [24.21] and vegetarian bonnetheads [42.33].

Of course, sharks are not only important ecologically, but also for human lives and livelihoods. We take a bit of time to talk about shark fisheries and sustainability, and their importance to some of the poorest nations in the world [44.37]. We also discuss the dangers of misinformation, especially on social media – sharks matter, but so does our perception and knowledge of sharks [49.20]. Luckily, David has written a book to address these issues and raise public awareness and support for sharks. It’s called Why Sharks Matter, and you can get it now!

About our guest

Dr David Shiffman

Dr David Shiffman is a Washington, DC-based marine conservation biologist who studies sharks and how to protect them. An award-winning writer, educator, and public speaker, his writings have appeared in National Geographic, the Washington Post, Scientific American, and a monthly column in SCUBA Diving Magazine. His new book, Why Sharks Matter: A Deep Dive with the World’s Most Misunderstood Predator, is available now from Johns Hopkins University Press. You can follow him on Twitter, Facebook, and Instagram @WhySharksMatter, where he’s always happy to answer any questions anyone has about sharks. 

You can check out his new book, Why Sharks Matter, here: https://www.press.jhu.edu/books/title/12267/why-sharks-matter