The oyster crops in the Ebro Delta began in the 1970s as a complementary production to that of the mussels. Its cultivation begins with the end of the collection of the mussels, towards January or February, fact that allows a perfect rotation between the two molluscs. In recent years the production of oysters in the Tierras del Ebro region has spread thanks to the increase of commercial interest that has originated the quality of its meat. There are currently more than 100 nurseries and 35 companies producing mussels and oysters.