The main culprit appears to be environmental deterioration caused by rising seawater temperatures, which reduce catches. The resulting low incomes make it exceedingly difficult to sustain a living. Efforts are underway to improve the marine environment and secure new sources of revenue for divers, but there appears to be no silver bullet. Some locals are concerned that the culture of ama divers could cease to exist in generations to come. [...] In 2017, the central government designated the ama fishing method of Toba and Shima as an important intangible folk cultural asset. Two years later, Toba and Shima were recognized as a Japan Heritage Site by the Agency for Cultural Affairs.