Wild abalone populations on the U.S. West Coast and worldwide have been decimated by predation, disease, loss of habitat and overfishing. However, farmed supply is alleviating the harvest shortfall; worldwide, more than 15 abalone species are commercially cultivated. The most popular and common abalone in the North American market is the red abalone (Haliotis rufescens), available as farmed product from California and both wild-harvested and farmed from Mexico. The only viable population of black abalone (H. cracherodii) in North America surrounds San Miguel Island off the southern California coast. The average size of wild-caught abalone is 12 inches, with meat weight averaging 1 pound per animal. Farmed abalone average about 4 inches in length. Grown either in onshore saltwater pens or in suspended cages, farmed abalone take three to four years to reach marketable size of four to six live animals per pound.