"This dyeing tradition came under threat in Oaxaca during the early 1980s when a Japanese company, Imperial Purple Inc., overharvested them. Instead of allowing the mollusks to recover, they collected dye year round. Within four years, the population was severely depleted. Led by anthropologist Marta Turok and the Pinotepa shell dyers, the Mexican authorities were petitioned to protect the purpura habitat. Since 1988, only licensed Mixtec dyers are permitted to harvest dye, taking monthly turns according to the moon cycle, thus creating a healthy environment for the shellfish. The men of Pinotepa de Don Luis continue this practice, trading or selling the dyed cotton to their village women weavers."
https://www.clothroads.com/the-color-purple-purpura-shell-dyeing-in-oaxaca/ #ConservationScience