Illustration by Adam P. Summers
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This scan of Thoracocarax stellatus shows the beauty, and utility, of detailed CT imaging.

Illustration by Adam P. Summers

One Scientist’s Quest to Scan Every Species of Fish

An expert in biomechanics embarks on an ambitious plan to scan and digitize images of every species of fish known to humans—up to 33,000 of them—and learns surprising details along the way.

Adam Summers' bizarre fish odyssey began 15 or more years ago with a question: Why are sharks and rays able to move about like other fish even though their skeletons are composed of cartilage and not bone?

One day, to better understand how a particular type of eagle ray crushes clams for food, Summers used a computed tomography (CT) scanner to digitize the ray. By meshing X-rays from different angles into a three-dimensional image, the scanner gave Summers a clearer picture of this sea creature's internal structure.

In fact, digitized images offer such valuable insight into biology, behavior, and animal history that Summers’ interest ballooned into an ambitious global project. Beginning earlier this spring, this University of Washington professor set out to scan and digitize all 25,000 to 33,000 fish species on Earth—from the Amazon River's spotfin hatchetfish, to the fringed filefish that hover in western Atlantic Ocean seagrass beds, to the spotted gars found in Lake Michigan.

A professor based at the Friday Harbor Labs in Washington State's San Juan Islands, Summers had long realized that such images could help solve basic riddles of biomechanics. He also is well known for creating intricate, beautiful images of fish by staining specimens with multiple colored dyes. (Read more at: Amazing Pictures of See-Through Fish.)

"I look at how fish stick to things, how they burrow, how we can use the natural world as an inspiration for new materials and new ways of doing things," says Summers. "I can use the skeleton of burrowers as inspiration for robots that burrow. I'm also working on a project that involves armor—how fish armor has evolved, how they solve the problem of being armored but still being maneuverable."

But scanning is so expensive that when he first began creating these images as a graduate student at the University of Massachusetts Amherst and at Harvard University's Museum of Comparative Zoology, he mostly begged for time on scanners at Boston-area medical centers.

"I didn't have money to pay for it, so I traded Snickers bars and fun stories with CT scan operators at hospitals," Summers says, laughing.

When technology improved, he raised $340,000 in private donations and purchased a topnotch scanner last fall. He installed it 150 feet from the water and began to see greater possibilities.

“We can scan things that inspire us directly from nature,” he says.

The machine allows Summers to scan small creatures and animals up to about the size of two grapefruits. He lets other researchers use the machine, but limits the subjects to specimens from museum collections. He uploads the images to the web and allows them to be accessed for free at Open Source Framework. He is trying to make arrangements with other scientists to digitize larger species, such as tunas and billfish.

"Having it right down the hall from me changed my thinking about how to use it," Summers says.

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This scan of Enophrys taurina shows some of the detail that scientists can harvest to better understand living things.

Rather than scan one animal at a time, Summers now often scans several specimens at once, saving both money and time. He recently scanned 13 species of surf perch—half the diversity of the group—in a single outing. Things that used to take weeks could suddenly be done in hours.

The idea of scanning all of the world's fish had once been a pipe dream that threatened to take decades. Now he suspects, with enough outside help, he'll be able to scan them all in a few years. Thus far he has scanned 540 species, including the Cornish lumpsucker, typically found amid small rocks in the sea around Ireland, the blue and yellow forktail blenny, and the Arctic’s tubenose poacher.

Summers is constantly amazed by the many ways researchers find to use the data.

"I and some of my colleagues end up learning fundamentally different things because we're seeing things a different way," he says.

Other biologists have started using his images as reference materials. Scans from skulls of different species of sculpins offered clues about why some live in shallow water, while others reside only in the deep. His images of surf perch, in which only some species have a second set of molars deep in their mouths, is helping unravel mysteries about their evolution.

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Trinectes maculatus, or hogchoker, is another example of the diversity of form in fishes.

"The only bottleneck is I have to train whoever comes here to scan, and I'm on a really small island that doesn't have really great internet connectivity," Summers jokes.

Even so, the scientist is already at the beginning stages of his next project. He'll be working with scientists in Florida who hope to scan and digitize every vertebrate on land and sea.

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