Why Sharks Matter

A Deep Dive With the World’s Most Misunderstood Predator

David Shiffman, PhD
Why Sharks Matter book cover. It is a photo of two sharks close together over soft corals.
Find it on Bookshop


This book is true to its title: a deep dive into why sharks matter. A man who loves sharks, science, and public outreach has written a book at the intersection of those things.

So much about what you think you know about sharks is wrong. Don’t worry, Shiffman has you covered. (For daily shark education, follow him on Twitter or Mastodon at @WhySharksMatter). Why Sharks Matter is full of mythbusting and pop culture references, with an appropriate balance of humor and facts.

Shiffman has an unabashed love for sharks. He is unapologetically nerdy—a term I use personally with pride. He even adds some humor at his own expense, such as when a recreational shark angler called him a “pompous pale-skinned bookworm”.

This is one of the most educational books I’ve read in a while, written in a way that makes the content fun. Whether you’re obsessed with sharks or a little scared by them, give it a read!

Main Points

Shiffman opens the book with this quote from Senegalese environmentalist Baba Dioum, which explains the philosophy behind the book:

In the end, we will conserve only what we love, we will love only what we understand, and we will understand only what we are taught.

He then begins to cover everything you need to know about why sharks matter. The book includes the basics, some fun facts, why sharks are not a threat to humans, the threats to sharks, their ecology, conservation options, different types of fishing policies, current research projects, current activism, and what you can do to help them.

There is so much information I’m not going to go into it all— you should buy the book! I’ll just highlight some of my favorite parts, which were especially memorable or educational for me.

Shark Facts

US Navy Seals jokingly say that you can test whether there are sharks nearby by dipping your finger in the water and tasting it—if it’s salty, there are probably sharks around.

Sharks are everywhere. They’re more common in some places than others, but they are pretty much global. The above quote is funny and more or less accurate, but did you know sharks can also be in freshwater?

Since I am an ecologist, the section on shark ecology was the most straightforward to me. But given my understanding of how complicated ecological theory can be, I recognize that Shiffman did an excellent job of simplifying the concepts for the average reader.

You have probably never heard of concepts like trophic cascades and keystone species. Those were drilled into my head as an undergraduate and graduate student, and I know all the classical examples. But Shiffman applied them to sharks in a simple yet accurate way.

Realizing that sharks aren’t that dangerous to humans is sometimes an important first step in convincing people of the need for shark conservation. However, simply acknowledging that these animals are not bad is less powerful than understanding that they’re actively good, and that bad things happen without them.

It’s hard to study the ocean and the things in it. Saltwater is not a natural habitat for humans. And the ocean is really big, as Shiffman reminds us:

I’m always stunned when people seem surprised about the discovery of a new underwater species or the fact that we can’t find a crashed plane after it was lost at sea. The ocean is really big, y’all. It makes up most of the habitat on Earth, and we can only look at a little bit of it at a time. [Which doesn’t mean that megalodon is still alive.]

Read that again: Megalodon is not alive.


Shiffman is heavily involved in conservation, and accordingly devotes a large chunk of the book to talking about it.

Why do I support sustainable fisheries? Because they’re a vital contributor to global food security and livelihoods for people.

Shiffman explains the details behind conservation strategies that you may have never heard of. There is a nuance behind conservation work that I did not fully appreciate, and did not realize until reading Why Sharks Matter. Every location is different in its politics, culture, and environmental history that sets a unique context in which to create an appropriate management plan. The options are not just black and white—total bans or total freedom— there are in-betweens.

The Bikini Atoll, for instance, where the US military tested 23 nuclear bombs over the course of 12 years, is now off limits to fishing because of radioactivity. It may shock you to hear that the atoll’s marine ecosystem has recovered to the point that it has some of the healthiest coral reefs in the Pacific. To be clear, this implies that normal human fishing-related activities are worse for a coral reef than BLOWING UP A BUNCH OF NUCLEAR WEAPONS.

One of the more well-known ocean management strategies is establishing marine protected areas, or MPAs. They’re kind of like national parks for the ocean. Not every MPA is successful in protecting or restoring an ecosystem, and there are a variety of reasons for that. There are ways to increase the chance of success, however, as Shiffman details for us:

A 2014 study found that the most successful MPAs have five key features. They are (1) fully no-take, (2) relatively large, (3) well-enforced, (4) relatively old (because recovery takes time), and (5) far away from humans. You also need community buy-in.

Scientist Outreach

Shiffman closes with a call to help stop the flood of misinformation online. In the age of social media, anyone can say something that may not be true and have it seen and shared thousands of times. Scientists who know what they’re talking about need to try to dam that flood. If you see something you know is wrong, say something. It may feel fruitless but it probably isn’t:

Challenging such misinformation clearly and forcefully is therefore a critically important task for experts. You may not change the mind of the person you’re arguing with, but you’ll almost certainly change the minds of some people watching the exchange, even if you never interact with them directly.


While I love the movie Jaws, it did some harm to sharks’ PR. We need to move past the Jaws generation and teach people that sharks are good for the oceans and deserve protection. Remember:

  • Sharks are everywhere
  • Most sharks are not a real threat to humans
  • Sharks are important to healthy marine ecosystems
  • There are many different types of conservation strategies we can use to protect sharks
  • Challenging misinformation online is important even when it’s frustrating

Good job, David.

Want to read more? Find Why Sharks Matter here: Bookshop

The quotes above were gathered using Readwise. It’s a truly amazing app to help you remember what you read. If you want to try it out, use my link and we both get a free month 🙂

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You might also like my notes on:

Fuzz: When Nature Breaks the Law by Mary Roach

Merchants of Doubt by Naomi Oreskes and Erik M. Conway

The Brilliant Abyss by Helen Scales