Around the world, freshwater ecosystems support tens of thousands of unique species and hundreds of millions of people. Through the Megafishes Project, aquatic ecologist Zeb Hogan travels to the most endangered of these environments, striving to save critically endangered fish and the livelihood of people who share their habitats.

"If use isn't managed, we'll see more and more extinctions," Hogan warns. "Freshwater biodiversity conservation—including animals like the Mekong catfish, river dolphins, and otters—is every bit as important as the protection of animals like tigers and whales, perhaps more so. Let's strive to protect fresh waters the same way that we care for rain forest and coral reefs."

Hogan believes new approaches, investment, and research offer real hope to both fish and fishing communities. In Cambodia, for example, when fishermen catch vulnerable species, Hogan buys live fish. He studies and tags them, then releases them downstream from the fishermen's nets. The practice keeps more endangered fish alive and allows scientists to gain insight on fish migration patterns, habitat use, and mortality rates—knowledge, Hogan hopes, that will lead to the creation of no-fishing zones and more sustainable management of Cambodia's fisheries.

"Science is not our only tool," Hogan says. "Education and outreach are crucial, too. Because in many places, endangered species conservation is a brand new concept that must be introduced and made relevant."

To illustrate the point, Hogan highlights a book about fish conservation he and his colleagues created and distributed to Cambodian children. "It was wonderful to see them interested in the story. They read the book to one another and enjoyed identifying each fish," he says. "Cambodian children can identify more fish species than some biologists!"

"I also use photography to get people interested and excited about river conservation," Hogan adds. "A picture of a ten-foot-long fish takes your breath away."

But the fresh thinking doesn't stop there. Hogan is part of a science team working on a new project in an area in Mongolia famed for its giant salmon. With the help of international donors, local residents are establishing a concession system through which an ecotourism company pays to run catch-and-release fly-fishing trips. No fish are harvested, and local people are given an economic incentive for conserving the resource.

The world's biggest freshwater fish, many of which weigh more than 200 pounds, face the biggest threats. That's why Hogan is undertaking a global survey of giant freshwater fish. "Many of the places I hope to explore have been virtually untouched by scientific study," Hogan notes. "It's a real chance to make discoveries about local biodiversity, compare the ecology of different river systems, provide new observations on animal behavior, and perhaps even discover new species."

"The mystery of not knowing exactly what is out there makes it terribly exciting," he adds. "By working with a network of other experts, I hope to help create a new body of information on the comparative ecology and conservation of the world's largest fish."

"I've been interested in fish, rivers, and streams as long as I can remember," Hogan continues. "I love research, science, and exploration. These projects allow me to combine all of those things and to convey my excitement to others, who I hope will take action to protect these amazing places and animals."