Together with Dr. Zeb Hogan, I am writing a book about the plight of the world’s largest freshwater fish species. The book is being published by University of Nevada Press in the U.S. and Canada in the fall of 2020.

Mysterious giants swim beneath the surface of the world’s rivers and lakes. They are a diverse assemblage of poorly understood creatures, from gargantuan gars to sumo-sized stingrays. Enormous in size and voracious in appetite, these ancient fish – some of which have been around for hundreds of millions of years – play critical roles in their freshwater ecologies. Yet their numbers are dwindling. Threatened by overfishing, habitat loss, dams, pollution and climate change, more than 70 percent of the world’s freshwater megafish are today at risk of extinction.

As an aquatic ecologist and host of the National Geographic Channel’s “Monster Fish” series, Dr. Zeb Hogan has spent more than a decade searching for and studying these increasingly endangered river titans. In this book, he teams up with award-winning journalist Stefan Lovgren to tell for the first time the remarkable and troubling stories of the world’s megafish, and the complex cultures and places that depend on them. It’s a story that stretches across the globe, from the most remote locations on Earth into our own backyards, chronicling a race against the clock to find and protect these ancient leviathans before they disappear forever.

The Megafishes Project, spearheaded by Zeb and supported by the National Geographic Society, was born as the first global attempt to document and ultimately help protect the planet’s freshwater giants. The quest to find the world’s largest freshwater fish provided the hook for the project, and it provides the narrative thread that runs through this book.

But the story is about more than that; it’s the story of the health of the world’s rivers and lakes too. Megafish, which are often the first to be overfished and suffer from habitat loss, are good indicators of how rivers are doing overall. The troubled story of the giant fish underlines the environmental crisis that many rivers and lakes around the world face today, with their biodiversity declining at a rate far greater than those seen in the oceans or on land.

It’s a story that, until now, has remained largely untold. Freshwater fish are every bit as important to the health of their ecosystems as the top predators of land and sea, and they deserve the same attention we give to tigers and whales.