Green Urchin

The green urchin is a dark yellow sea urchin species that can be found in the kelp forests. Though its name is technically inaccurate, the urchin does appear to be a green colour when deep underwater.

Anatomy

Green urchins are recogniseable through their long spines, which grow in rows across their bodies. These long spikes flare out at the tip, giving them an arrow-like appearance with a sharp, pointed end. These spines are hollow and contain an viscous black liquid that is toxic to most species. The urchin is able to regrow these spines if they are removed, and so can be harvested without permanent damage to the organism. Because of the hollow nature of these spines, they are often used as writing implements, and can last incredibly long as such.

Ecology & Habitat

The green urchin is incredibly sensitive to changes in salinity, water temperature, and even depth of its surroundings. Though it will not die if brought to a different habitat, it will struggle greatly and will generally become under-nourished. The species is eaten by a few different species, though its primary predators are the ocean centipede and the leaf otter. The ocean centipede is able to withstand the toxins of the green urchin, but the leaf otter simply smashes the species open with rocks to get to the edible and non-toxic interior without touching its spines.

Scientific Name

Psammechinus viridis

Geographic Distribution

• Kelp Forests

Uses & Byproducts

The green urchin's spines are used to create a writing implement called a greenpen. The green urchin has a significant amount of spines, so farming is often not required for them to be harvested. When they are farmed, it is typically on a very small scale.