FDA helps create DNA database for fish

When Kent Carpenter and Jeff Williams go shopping for fish, they're not looking for a good price or even the best tasting fish, what they want is variety.

"The Filipinos eat every species of fish," says Carpenter. "Even small ones."

While shopping at a market in Batangas City frequented by locals in the central Philippines, Carpenter discovers "a lot of fish, a lot of odor, and a lot of slime as well."

Carpenter is a fellow with the California Academy of Sciences in San Francisco. Williams is with the Smithsonian in Washington, D.C. These guys know their fish. But even for experts, it's sometimes tough to tell one kind of fish from another, especially if it's cut up.

Seventy percent of the fish sold in the United States is imported. Most is labeled correctly, but the FDA has found many cases where it's not. So the FDA is helping create a DNA database for fish to help identify what's what.

"This is something that's important for food security, both in the United States and the Philippines," says Carpenter.

Unscrupulous exporters sometimes substitute cheap fish for expensive ones. Even worse, poisonous species like the puffer fish are sometimes mislabeled, and people who eat it get very sick.

"That did happen, within the last few years, a large quantity of puffer fish specimens were sold as monkfish in the U.S.," says Williams.

Carpenter and Williams spent three weeks in the Philippines searching for fish.

"The fish markets in the Philippines have some of the highest diversity in the world," says Williams.

On a good day, they "collected anywhere from 80 to 100 species," says Williams. They then took the fish to a make-shift lab to process while it's still fresh.

"Very long day," says Williams. "We've been doing 16, 18-hour days."

Each fish is suspended in a tank and photographed before its original color fades. The fish is preserved and scientists take a tissue sample. Those samples are sent to a lab like the one at the Academy of Sciences in Golden Gate Park. It takes a couple of days to treat them, run them through a genetic analyzer, and get a DNA sequence. Then researchers look at one specific gene believed to be unique to every species.

Lettered code is what separates the perch from the snapper. The FDA hopes to use it in the future to spot check fish coming into the country.

On this trip, the team collected nearly 400 species of fish for the database. They will be back next year for more.

The FDA is hoping to begin field testing at least some imported fish as early as next year. They will compare the fish DNA with the 8,000 samples already entered in a global database called the "Fish Barcode of Life." But that database is still a long way from being complete. There are believed to be about 30,000 species of fish.

Written and produced by Jennifer Olney.

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