Black Abalone - Conservation Status

Conservation Status

Black abalone are listed on the International Union for Conservation of Nature's Red List as Critically Endangered (CR A4e). On June 23, 1999, the U.S. National Marine Fisheries Service (NMFS) designated the black abalone as a candidate for protection under the Endangered Species Act (64 FR 33466). On December 21, 2006, the Center for Biological Diversity submitted a petition to NMFS to list the black abalone. On January 11, 2008, NMFS completed their status review of the species and proposed that it be listed as endangered (73 FR 1986). Black abalone were listed as endangered on January 14, 2009 (74 FR 1937). The NMFS proposed a critical habitat of 390 square kilometers for the endangered black abalone on September 28, 2010. The State of California has introduced an Abalone Recovery Management Plan to guide conservation efforts.

Black abalone have dramatically declined in numbers throughout their historical range, and are locally extirpated in certain areas. This decline was initiated by overfishing. Following World War II, the California abalone fishery was not managed for individual species. Therefore, it resulted in a systematic depletion of various abalone species as the fishery over-harvested one species and then moved on to the next in an attempt to meet demand. Black abalone were the last to be targeted, with the peak harvest occurring in the 1970s. Additionally, improved harvesting technologies that expanded the harvesting areas and supported larger harvests per unit effort were not initiated. Now, all abalone fisheries in California are managed by the California Department of Fish and Game, which restricts the size of abalones caught, and the season in which harvesting can take place. In Mexico, there is a total allowable catch limit for black abalones. Even though harvesting black abalone is regulated in California, poaching still occurs. Other threats include coastal development for residential areas, harbours and waste discharges, compounded by commercial and recreational fishing of the black abalone.

The depleted stocks of black abalone were further reduced by Withering syndrome, first discovered in 1985, when commercial fishermen reported large numbers of empty shells and dying abalones on the shores of several of the Californian Channel Islands (including the islands of Santa Cruz, Anacapa, Santa Rosa, Santa Barbara, San Miguel, and San Clemente). This disease impairs the production of digestive enzymes, effectively starving the abalone to death. Following onset of symptoms, the animal usually quickly dies. In many locations, percentages greater than 90% of individuals have been lost, and in some places, a total loss of the black abalone population occurred. The disease spread from the Channel Islands to the mainland coast in 1992, where it devastated most populations in warmer waters south of Point Conception or in locally warmer waters further north.