In a new study published last week in the journal Conservation Letters, researchers from Scripps Institution of Oceanography, UC San Diego, and REEF demonstrate that fish population data collected by volunteer scuba divers and snorkelers (i.e. citizen scientists) provide a powerful and accurate tool to track species trends and biodiversity.

Led by Dr. Dan Greenberg and Professor Brice Semmens, the study focused on evaluating the effectiveness of the REEF citizen science data in monitoring trends of coral reef fishes along Key Largo, Florida, over a span of 25 years. Using REEF volunteer observations, and sightings data from a rigorous, federally-funded survey, the researchers analyzed data from approximately 90 species to determine the level of correlation between the two methods.

Despite the unstructured nature of citizen science surveys, the findings were overwhelmingly positive. "The large majority of species exhibited strong temporal correlations between the two data sets," explained Professor Semmens. "Our findings clearly indicate that citizen scientists can produce high quality ecosystem monitoring data that are on par with data from a long-term, statistically designed survey carried out by professional scientists."

The state of biodiversity worldwide has long been shrouded in mystery, primarily due to the lack of comprehensive, long-term population monitoring data. However, this new research suggests that citizen science initiatives such as the REEF Volunteer Fish Survey Project can be one of the keys to unlocking crucial insights into ecological trends.

This research underscores the invaluable contributions that citizen scientists and other contributory research projects can provide to our understanding of biodiversity. By engaging the thousands of scuba divers and snorkelers in marine life observing and reporting, REEF has harnessed a vast network of observers to track ecological changes and inform marine conservation. For more information about the study, please refer to the open-access article published in Conservation Letters here: To see other scientific papers that have included REEF data, visit