The black abalone – a large edible sea snail found along the Pacific Coast of California and Baja, Mexico – was recently added to the federal Endangered Species List.

Scientists say the mollusk, once a common sight in tide pools up and down California’s coast, could be extinct in 30 years. Over-harvesting, coupled with a ruinous disease, is largely to blame for the species decline. It has also been suggested that changes in the ocean’s chemistry associated with climate change may partly be behind the die-off.

The abalone has been almost completely wiped out from beaches in Southern California and the Channel Islands. Scientists say the mollusk’s population is just 10 percent of its historic value.

In addition to losses sustained from harvesting, a devastating disease – known as withering syndrome – has decimated abalone population across a wide swath of their range. Considered the primary threat to the mollusk, withering syndrome originated in the Channel Islands.

It was the warm waters discharged by the Diablo Canyon Nuclear Power Plant in San Luis Obispo County, however, that gave the disease a foothold on the mainland. The disease has since spread all over Southern California and as far north as Monterey County.

The petition to have the marine species added to the list was first accepted in April 2007, with news of its addition released yesterday. The petition was authored by the Center for Biological Diversity.