In May, Japanese fisherman Tadasuke Nakamura noticed he had an abnormally large haul of bluefin tuna in his set net off the Pacific coast of Hakodate, on Japan’s northern island of Hokkaido. Hundreds of the prized sushi fish crowded the net, but he had to let many of them go. Japan has an annual catch quota and if ‌Nakamura had kept the haul he would have had no quota left for the colder months when bluefin tuna are fattier, tastier and fetch a higher price. “It’s truly upsetting to have to...