Japan's salmon fishing industry, a key driver of the country's food culture, peaked in the 1990s and 2000s as artificial hatching and release programs expanded. Juvenile salmon, or fry, released in Hokkaido and the northeastern Tohoku region head out to sea in spring, staying in coastal waters until summer. In fall, they migrate north through the Sea of Okhotsk, the Bering Sea and the Gulf of Alaska, where they grow and migrate seasonally before returning to Japan after about four years. But a crack has emerged in this cycle. According to Kaeriyama, pink salmon, which thrive in colder waters, are rapidly increasing in the Bering Sea in the northern Pacific Ocean due to rising sea temperatures caused by global warming. Because pink salmon feed on the same nutrient-rich zooplankton as chum salmon, intense competition has ensued, with chum salmon losing the battle for food and struggling to grow, leading to their decline, he said. With fewer salmon returning to Japan, securing eggs for artificial hatching has been difficult. An association to promote the breeding of salmon and freshwater trout in Iwate Prefecture in northeastern Japan had received about 40 million of the 60 million eggs hatched in fiscal 2023 from Hokkaido, but due to a shortage of eggs in Hokkaido, the association said it had received none this fiscal year.