Kelp forests are the rainforests of the sea. These highly productive ecosystems provide food and habitat to over 700 species of invertebrates, other algae, and fish, many of which are popular with sport and commercial fishermen and recreational divers. Over the past 100 years, the Palos Verdes Peninsula has lost approximately 75% of its giant kelp canopy. Sedimentation, development, urban runoff and storms slowed kelp growth. At the same time, the loss of key urchin predators and competitors allowed urchins to overrun the reef and devour the remaining kelp. If left alone, kelp forest recovery may take decades or may never come back at all. Manually culling the urchins jump starts the return of a healthy kelp forest and healthy urchins. Approximately 150 acres of urchin barren were identified along the nearshore coast of Palos Verdes.
With funding provided by the Montrose Settlements Restoration Program, restoration efforts led by The Bay Foundation began in 2013 to reduce the urchin population density to allow the recovery of giant kelp. In partnership with environmental groups, public aquaria, fishermen and researchers, nearly 7000 hours underwater has resulted in the restoration of 39 acres of rocky reef. The kelp forest community has responded positively to the reduction in sea urchin density as indicated by the development of a variety of macroalgae species and, increased invertebrate and fish species richness and biomass. More kelp, means more food for red sea urchins on the peninsula. The improved condition of the red urchins has added value and opportunity for the Commercial Sea Urchin fishery. Further monitoring efforts will provide a more accurate understanding of the strength and persistence of the ecosystem responses to this work in the coming years.