Pacific bluefin tuna

"One of three bluefin species, the Pacific bluefin tuna is a powerful swimmer — built for endurance and speed. This highly migratory fish can travel thousands of miles at a stretch, crossing the Pacific Ocean to reach spawning grounds in as little as fifty-five days . . . During the months of April through August, they spawn in the Western Pacific Ocean between Japan and the Philippines. When they are about one year old, some of the juvenile population migrates over 5,000 miles (8,000 km) to the Eastern Pacific Ocean near Baja California, Mexico. After remaining there for a few years, the tuna return to their Western Pacific Ocean spawning grounds." Pacific bluefin tuna have been subject to devastating overfishing. In Japan specifically, the species is sought-after by sashimi and sushi consumers. Larger tuna are specifically targeted, some have been known to sell for millions of dollars. Current wild populations have been estimated at 3% of historical, pre-fishing, levels.