REEF Data Used To Evaluate Effect of Marine Reserves in the Channel Islands

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Kelp bass, one of the 25 species included in the analysis of marine reserves in the Channel Islands. A harvested species, this species showed a positive effect of marine reserves through time.
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A REEF volunteer descending to conduct a survey in one of the Channel Islands marine reserves. Photo by Carl Gwinn.

REEF Director of Science, Dr. Christy Pattengill-Semmens, joined a dozen other scientists in presenting the findings of monitoring the marine protected areas (MPAs) in the Channel Islands, California, earlier this month during a special session of the California Islands Symposium.   The presentation highlighted the effect of reserves on common nearshore rocky reef fishes based on 10 years of REEF survey data.  During this time, REEF volunteer divers have collected 1,595 visual fish surveys from 113 sites throughout the Channel Islands before and after state marine reserves were established in 2002.  Using analysis methods developed to analyze volunteer bird watching data, collaborators Dr. Brice Semmens (NOAA NMFS) and Dr. Steve Katz (Channel Islands National Marine Sanctuary) developed a model to detect trends in fish densities. The analysis included 25 species of common rocky reef fishes, including targeted and non-targeted species. Rather than focusing on changes in the density of individual species, the analysis evaluated changes in multiple species to characterize responses of marine communities to protection from fishing in reserves.  The analysis suggests that reserves are positively influencing fish population trajectories in both targeted and non-targeted species.  On average, fish populations had ~20% higher growth rates inside reserves as compared to outside, although there was a high degree of variability across species.  Dr. Pattengill-Semmens notes that this study is one of the first applications of Pacific region REEF data for use by marine resource agency officials to evaluate the effects of management actions.  The results will ultimately be published and will join the many existing published studies of the utility of Tropical Western Atlantic REEF data.  The cumulative impact of the data and results from the entire suite of monitoring programs being conducted around the Channel Islands will "help to inform future management of the region, aid in the implementation of the California Marine Life Protection Act in southern California, and contribute to our understanding of MPAs worldwide," said John Ugoretz, manager of the Marine Habitat Conservation Program for the California Department of Fish and Game.   To find out more about REEF monitoring activities in the Channel Islands, visit the Channel Islands project webpage.

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