Degredation of Rocky Reefs (IMAGE) University of California - San Diego Caption Rocky reefs can exhibit stages of human impact: (a) a healthy reef with a variety of species, in particular large top predators; (b) big fish removed through overfishing; (c) barren reefs emerge because populations of species such as sea urchin increase; and (d) reefs covered by sediments due to a lack of species that previously filtered and removed sediments, along with an influx of sediments coming from activities such as shrimp trawling. Credit Scripps Institution of Oceanography, UC San Diego Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.