Sea Lion Cove lies on the Mendocino coast just south of Point Arena, about 16 miles (26 km) northwest of Gualala and three miles (4.8 km) southwest of Manchester, California. It forms part of a marine protected area covering 141 acres (57 ha) of coastline. Numerous circular coves and sea caves mark this stretch of shore, which may be the most extensive example of littoral pseudokarst topography on the Pacific coast.

Littoral pseudokarst is produced by marine erosion and is often characterized by the littoral sinkhole: an opening to the surface formed by collapse or gradual erosion into a sea cave chamber or passage. Unlike karst topography in soluble rocks, littoral sinkholes form almost entirely through erosion and collapse rather than dissolution. They are also known as “punchbowls” or “blowholes,” though the latter term properly applies to caves that eject spray with incoming waves, a phenomenon dependent on both tide level and swell conditions. 

Sea Lion Cove State Marine Conservation Area is one of 22 marine protected areas adopted by the California Department of Fish and Game in August 2009, during the second phase of the Marine Life Protection Act Initiative, which took effect on May 1st 2010. The initiative is a collaborative public process to create a statewide network of protected areas along California’s coastline. Local divers, fishermen, conservationists and scientists, who formed the North Central Coast Regional Stakeholder Group, designed the reserve to preserve sensitive sea life and habitats while enhancing recreation, study and education. Within the area, commercial and recreational take of invertebrates, algae and other plants is prohibited, though the take of all other species is permitted.  Read more here and here. Explore more of Sea Lion Cove and Point Arena here: