People look at Pacific bluefin tuna as it swims in tank in Tokyo Sea Life Park in Tokyo
People look at a Pacific bluefin tuna as it swims in a tank in the Tokyo Sea Life Park in Tokyo, April 2, 2015. All but one of the nearly 160 tuna and bonito fish have died for unknown reasons over recent months, leaving this one tuna the last remaining fish of the vast tank's original population, local media reported. REUTERS/Thomas Peter
