laboratories and then relocated. Returning the mature individuals into the wild can have a positive effect on the urchin density of the reef. The increase in population can also be aided by the artificial building of reefs: material such as concrete can encourage the growth of coral, and provide more niches for the urchins to hide from predators such as larger fish. When there are still some areas of high-density urchins, it is possible to relocate urchins to other, low-density reefs. With these methods and the help of volunteer workers, it seems that the shift back to coral-dominated reefs and away from algae-dominated reefs is possible. When re-locating Diadema it is necessary to remove most mature algae from the re-location area since there are toxins in mature algae that kills the Diadema. References Marine Inverebrates of Bermuda Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates External links Microdocs : The sea is green Diadema re-location website. antillarum Fauna of the Atlantic Ocean Fauna of the Dominican Republic Animals described in 1845 Taxa named by Rodolfo Amando Philippi