Sea urchin
Sea urchins or urchins () are typically spiny, globular animals, echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal to . Their tests (hard shells) are round and spiny, typically from across. Sea urchins move slowly, crawling with their tube feet, and sometimes pushing themselves with their spines. They feed primarily on algae but also eat slow-moving or sessile animals. Their predators include sea otters, starfish, wolf eels, and triggerfish.
El Salvador
There are eight species of sea turtles in the world; six of them nest on the coasts of Central America, and four make their home on the Salvadoran coast: the leatherback turtle ("Dermochelys coriacea"), the hawksbill ("Eretmochelys imbricata"), the green sea turtle (black) ("Chelonia agasizzii") and the olive ridley ("Lepidochelys olivacea"). Of these four species, the most common is the olive ridley turtle, followed by the green sea turtle. The other two species, hawksbill and leatherback, are much more difficult to find as they are critically endangered, while the olive ridley and green sea turtle are in danger of extinction.