The menu items were the same for each participant, Dr. Bray said, but a participant on the low-protein diet would have gotten more mayonnaise and less tuna in a tuna fish salad, while the high-protein diet was extra tuna with little mayonnaise.

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Atlantic bluefin tuna -- the most high-priced ocean fish in the world -- have declined by about 90 percent since the 1960s due to overfishing.

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There is a premium for line-caught fish: hake, monkfish, tuna.

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Few foods contain it naturally -- mainly fatty fish like salmon, mackerel and tuna, as well as liver and egg yolks.

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For fish, his go-tos are smoked salmon and cucumber or tuna salad.

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Darker-fleshed fish that swim in cold, open waters, such as tuna, herring, and mackerel, store fat in their flesh and are high in omega-3s.

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Ceviche, tuna tostadas and taquitos, plus various meat and fish dishes cooked over a wood-burning grill, are presented on beautifully decorated places and enamel bowls.

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The work makes clearer who does and does not benefit from taking supplements of omega-3 fatty acids, the good oils found in fish such as salmon, tuna and sardines.

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As Bill Brown and his crew tied down his 50-foot boat, the Jamie B, he said his biggest concern was losing work days to fish tuna.

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