...when you can invest in blue fin tuna instead! An endangered bluefin tuna was caught last and weighed in at 232-kilograms. This single tuna sold for an all-time high of $175,000 to two Japanese restauranteurs—60 percent higher than last year's record. That breaks down to $21.38 an ounce—almost three dollars more per ounce than the cost of silver. (And by the time it reaches the dining table as sushi, it will be more like the cost of gold.) I wouldn't worry about bluefin tuna being on the menu for very long, or anywhere else for that matter.