At the markets, “Kuro maguro” is a mix of two types of fish. One is the Atlantic (or Northern) bluefin tuna, which takes a long migration route from the east coast of North America to the Black Sea and spawns around the Mediterranean Sea. The other is the Pacific Bluefin Tuna, which migrates across the Pacific Ocean from the seas around Japan to the west coast of North America, and spawns in Japanese territorial waters. These two types are subspecies (some believe they are actually different species), they look almost exactly the same, both have lifespans of 30 years and grow to nearly 400 grams at full size. The differences are really only the shape of the abdominal cavity when dissected.
Atlantic (or Northern) bluefin tuna from New York, Boston and Canada are ranked higher, followed by those from Spain, Malta and Croatia, which have slightly inferior meat. In particular, the areas in the ocean where Irish Atlantic (or Northern) bluefin tuna is caught in the northernmost of the cold regions so the water temperatures are very cold. Therefore, the meat of the fish body firms and grows more fat to protect the internal organs from the low water temperatures.
Generally, Generally, Atlantic bluefin tuna from the Northern Atlantic has both fat and umami, and normally the price is comparable to wild Pacific Bluefin Tuna in neighboring waters. Toyosu Market does not distinguish between the two types of Kuro maguro.
Types of tuna
Types of fishing method
The US Canada Spain Malta Croatia
Autumn – Winter