Long-term monitoring of black abalone populations and their habitat has been ongoing throughout the California coast, in some areas since the mid-1970s. NOAA Fisheries continues to support these monitoring programs because the data provided are critical to assessing the status and recovery of black abalone. For example, these monitoring efforts allowed researchers and resource managers to detect the mass mortalities of black abalone that occurred in the 1980s and 1990s and to track the spread of the disease through the Channel Islands and northward along the mainland California coast. Since then, continued monitoring has confirmed the local extirpation of black abalone at many sites, as well as the persistence of black abalone at several locations. Monitoring has also detected recent recruitment events and increases in black abalone numbers at a few local areas.