An external tagging technique for the long-spined sea urchin Diadema aff. antillarum

An in situ tagging technique for the long-spined sea urchin Diadema aff. antillarum , suitable for carrying out short and medium term ecological studies is described. It is a simple method in which external nylon tags are anchored in holes drilled through the urchin test. The technique was tested in the field and found to be effective for individuals of more than 20 mm test diameter in terms of survival and tag retention rates.