Changing Planet

Palau Expedition: The Sea Was Boiling With Fish

In September 2013, Palau’s current President Tommy Remengesau announced his intention to protect 80 percent of Palau’s waters as a National Marine Sanctuary. For the month of September 2014, National Geographic Explorer-in-Residence Dr. Enric Sala is leading key scientists and filmmakers to explore, survey, and document the diversity and abundance of the marine life that will be protected by the new offshore sanctuary. The team will also assess how well inshore marine protected areas have performed to date.

The lagoon was calm as we were motoring on the German Channel, a cut blasted on the reef and dredged by the Germans at the beginning of the 20th century. The sky looked like a dreamy scene of cottony clouds, the type of picture urban people have on their office walls or screensavers. And then the sea boiled in front of us.

We donned our masks and snorkels and jumped in the water. There were tens of thousands of silvery fusiliers, swimming together closely near the surface, forming a giant ball. We heard a bang, and the ball exploded. It had happened in a flash. Where all the numberless prey fish had been, there were now just two giant trevallies. That’s why these extraordinary aggregations of small fishes are called bait balls—they’re bait for ocean predators.

Photo by Enric Sala. 2014 Pristine Seas Palau Expedition
Two giant trevallies break up a bait ball and scatter fish in every direction. (Photo by Enric Sala)

The fusiliers reappeared from below us, followed by a school of fifty black snappers, each with a massive, round head and a fierce look. We had to keep kicking our fins to stay abreast of the bait ball.

The incoming tidal current was bringing water and food from the open ocean in the form of plankton. The fusiliers and the snappers consumed that food—a collection of microscopic organisms both plant and animal, some fully grown and still tiny, others simply newly hatched forms of creatures that would one day pursue these pursuers. Soon the giant trevallies, reef sharks, rainbow runners, and dogtooth tuna showed up, hunting for the small fish.

And then they came—two elegant ballerinas, materializing as ghosts from the darkness below, moving their giant wings gracefully. Manta rays, three meters across, were now feasting on the plankton, swimming with mouths agape. They looked like giant open barrels with wings, gliding back and forth, rolling beautifully and turning around, in a rhythmic dance. I was hypnotized and could not take my eyes away from them.

Two hours passed, and the sun set. Around us, the bait ball was being torn apart by the tuna, sharks, and other predators. Another loud bang, and again the bait ball became a living underwater firework. But still all we could look at were the mantas—caught in their spell as they silently filtered the plankton.

Black and white clouds above give way to a colorful underwater world below. (Photo by Enric Sala)

This is why people come to Palau from all over the world: to experience something unique, nature at its best. Our Pristine Seas expedition is exploring the wild side of Palau’s seas, but also what this means to the Palau economy. President Remengesau’s intention to create a large marine reserve offshore in the next few years has been welcomed by environmentalists around the world. But what will happen to the nearshore reefs people come to see?

Read All Pristine Seas: Palau Blog Posts

The Pristine Seas expedition to Palau is sponsored by Blancpain and Davidoff Cool Water.

Marine ecologist Dr. Enric Sala is a National Geographic Explorer-in-Residence who combines science, exploration and media to help restore marine life. Sala’s scientific publications are used for conservation efforts such as the creation of marine protected areas. 2005 Aldo Leopold Leadership Fellow, 2006 Pew Fellow in Marine Conservation, 2008 Young Global Leader at the World Economic Forum.

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (

Social Media