There are three species of bluefin tuna–Pacific, Atlantic and Southern. The largest of all bluefin species is the Atlantic bluefin, which can live over 40 years and weigh over half a ton. These fish are slow to mature and may not reproduce until they are 10 years old and over 300 pounds (136 kgs). Unfortunately for the bluefin tuna, they are highly valuable. A single Pacific bluefin recently sold for $396,000 on the Japanese market. That’s $526 a pound. Skyrocketing demand for bluefin in combination with mismanagement has lead to population declines in the Atlantic of up to 85% since 1970. Watch this Google Earth video showing the spawning grounds for Atlantic bluefin tuna.