Yellowtail jack (Seriola lalandi) at HSWRI in San Diego. Courtesy of HSWRI hide caption

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Kumu (sp. Parupeneus porphyreus). The Whitesaddle Goatfish has a special place in Hawaiian culture. In ancient Hawaii, the fish were used in offerings to the gods. Courtesy of Derek Yoshinori Wada hide caption

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Lake herring roe at the Dockside Fish Market in Grand Marais, Minn. Some workers at the market call it "Lake Superior Gold." Derek Montgomery for NPR hide caption

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Chris Tremblay, a member of the Passive Acoustics group at NOAA's Northeast Fisheries Science Center, deploys an underwater recording device along the Eastern Seaboard to listen for the mating sounds of Atlantic cod. Courtesy of Chris Tremblay hide caption

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Parisi Tsakirios, 29, mends a net as he prepares for another fishing trip. "I can't imagine doing any other job, because I love the sea," he says. "But there are hardly any fish. I barely break even. I can't support my family." Joanna Kakissis/NPR hide caption

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NOAA Fisheries biologist Nick Wegner holds an opah caught during a research survey off the California coast. Researchers say the opah is the first fish known to be fully warmblooded, circulating heated blood throughout its body. NOAA/Reuters/Landov hide caption

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Chef Marcus Samuelsson first fell in love with a version of this burger at a tiny fish shack in Barbados. Paul Brissman /Courtesy of Houghton Mifflin Harcourt hide caption

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Sweet or salty? Historically among Eastern European Jews, how they liked their gefilte fish depended on where they lived. This divide created a strictly Jewish geography known as "the gefilte fish line." Claire Eggers/NPR hide caption

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Researchers raised two groups of walking, air-breathing Polypterus senegalus — one on land and one on the water. They discovered that each group was able to adapt to be best suited to its environment. A. Morin, E.M. Standen, T.Y. Du, H. Larsson/McGill University hide caption

toggle caption A. Morin, E.M. Standen, T.Y. Du, H. Larsson/McGill University

Asian carp, battered and fried. As the fish makes its unwelcome way up the Mississippi River, chefs are trying to get people to eat to beat it back. Louisiana Sea Grant/Flickr hide caption

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These undated photos provided by the Colorado Division of Wildlife show the endangered greenback cutthroat trout and the Colorado River cutthroat trout. Federal and state biologists have stocked the wrong fish for more than two decades. AP hide caption

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Using dipnets --€” which have nets up to 5 feet in diameter at the end --€” isn't easy, and the river can get pretty crowded. Robert Carter, a novice dipnetter, holds up the first fish he caught after a day on the Kenai River. Annie Feidt/Alaska Public Media hide caption

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Yellowfin tuna; Chinook salmon; lingcod; Pacific halibut. Chang/iStockphoto; Debbi Smirnoff/iStockphoto; via TeachAGirlToFish; Andrea Pokrzywinski/Flickr hide caption

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The FDA is recommending that pregnant women eat 8 to 12 ounces per week of fish such as salmon, canned light tuna, tilapia or cod. Iakov Filimonov/iStockphoto.com hide caption

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Carp are collected at a breeding farm near the Belarus village of Ozerny in November 2013. Researchers say there's a lot the aquaculture industry can do to be more efficient. Viktor Drachev/AFP/Getty Images hide caption

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A tuna fishing boat drags a cage of nets on the Mediterranean sea in 2010. (The Mediterranean is not considered to be part of the "high seas.") Andreas Solaro/AFP/Getty Images hide caption

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A marlin caught as bycatch by the California drift gillnet fishery. The conservation group Oceana called the fishery one of the "dirtiest" in the U.S. because of its high rate of discarded fish and other marine animals. Courtesy of NOAA hide caption

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A fish that knows the way to go: the Chinook salmon, which appears to use the Earth's magnetic field to navigate ocean waters and rivers. Jeff T. Green/Getty Images hide caption

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