Research Areas > Regional Monitoring > Bight '08 Rocky Reef

Project: Bight '08 Rocky Reef

Background and Objectives

Rocky habitat provides some of the Bight’s most spectacular underwater scenery, and its giant kelp (Macrocystis pyrifera) forests are home to some of the most productive marine habitats on earth. While there are a number of rocky habitat/kelp forest monitoring programs, there is little integration among studies by different researchers regarding this unique habitat. The initiation of California’s Marine Life Protection Act and plans for a series of habitat reserves in Southern California brought an increasing need for Bight-wide assessment of rocky habitat condition. The Rocky Reef research component was added to the Southern California Bight (SCB) Regional Monitoring Program in 2008 (Bight '08). It provided an opportunity for more than 20 rocky reef biologists to collaboratively assess the health of rocky reefs throughout Southern California.

The goal of the Bight '08 Rocky Reef component was to answer three questions:

• What is the distribution of hard bottom habitats in the Southern California Bight?
• What is the range of natural biological conditions in these reef assemblages?
• How do these conditions correlate with anthropogenic factors?

Status

This study was initiated in 2007 and completed in 2011.

Methods

Starting in 2008, 69 reefs from San Diego to Point Conception, including the Channel Islands, were sampled by nine organizations. Quantitative biological information was collected, including algae and invertebrate species identifications, as well as fish identifications and size class measurements. All sampling was conducted by SCUBA divers investigating depths up to 90 feet.

Findings

The pilot rocky reef monitoring component in Bight '08 identified approximately 120 natural rocky reefs in the SCB, extending across 46% of the region's coastline. Giant kelp, Macrocystis pyrifera, was present at nearly all monitored reefs, and herbivorous sea urchins were found at 38% of the reefs. In addition, a total of 78 fish species were identified. Fish biomass density at some sites was on par with fish biomass at isolated or protected ecosystems in other parts of the world. There was a clear indication of fishing pressure on kelp bass and California sheephead in Santa Monica Bay. Investigation of anthropogenic water quality and/or fishing impacts was limited by the availability of assessment tools. New tools need to be developed, especially those that can differentiate among stressors associated with water quality and overfishing. Integration of additional data types would also improve the assessments. Nonetheless, the regional survey results can be used to inform follow-up actions and future survey designs.

Additional data on kelp canopy extent is available through the Regional Kelp Survey Consortiums, which conduct periodic surveys of kelp beds throughout the SCB.

Presentation

• Comparison of volunteer and professional rocky reef condition assessments - January 2011 presentation to SCCWRP member agencies comparing professional and volunteer-collected data for the Bight '08 rocky reef study.

Fact Sheet

• Bight '08 Rocky Reef Fact Sheet