In Santa Monica Bay, Rocky Reefs are primarily located along the coast off of Palos Verdes and Malibu where mountains essentially extend into the nearshore ocean. These rocky reefs are jumbles of rock. Formed by expanses of bedrock, 30x30x30 foot monoliths, (10 meters), and large fields of boulders, cobbles and gravels. Collectively these rocky reefs extend for miles along the coast, most being shallower than 100 feet, (30 meters) in depth. Notable exceptions to this exist near Rocky Point in Palos Verdes and Point Dume in Malibu. These shallow depths allow for ample light to penetrate the water providing the energy for algae and kelps to grow.
Giant kelp forests can dominate this Rocky Reef habitat extending from the rocks all the way to the surface. The physical presence of these kelp forests and all the crevices between the rocks provide a rocky reef/kelp forest habitat that is one of the most biologically diverse and productive habitats on earth. The giant kelp grows very quickly when there is ample light and nutrients. Thousands of these kelps growing in a forest together can slow water currents, impact small waves, increase dissolved oxygen, and support hundreds of marine species. This diverse and prolific assemblage of algae, fish and invertebrates make these rocky reef/kelp forest favorite spots for recreational and commercial fisheries, SCUBA diving, and snorkeling. For surfers having a kelp canopy on the surface helps keep the waves glassy all day.
Another form of Rocky Reef habitat exists in Santa Monica Bay comprised of the rocks used to build breakwaters, jetties, and offshore fishing reefs. Much of this rock was sourced from Catalina Island and barged over to create these features. The breakwaters off the Santa Monica Pier, Marina Del Rey, and King Harbor are the largest and may provide similar habitat value to naturally formed rocky reefs.