Strongylocentrotus droebachiensis, commonly known as the green sea urchin, is a species of echinoid native to the cold and temperate waters of the North Atlantic and North Pacific Oceans. It is found along the coasts of northeastern North America, Greenland, Iceland, northern Europe, and parts of Japan and Alaska. The species name droebachiensis refers to Drøbak, Norway, where the species was first described in 1776 by Otto Friedrich Müller. The genus name Strongylocentrotus derives from the Greek strongylos meaning “round” and kentron meaning “spine,” referring to its spherical body covered in spines.

Historically, the green sea urchin has been harvested by coastal peoples in northern Europe, the Arctic, and northeastern North America. In modern gastronomy, its edible gonads, known as roe or “uni,” are considered a delicacy in Japanese, Nordic, Greenlandic, and North American coastal cuisines. Overharvesting and ecological shifts have made it both a commercially valuable species and, in some regions, a destructive grazer capable of forming “urchin barrens” by overconsuming kelp forests.

This species' gonads are rich in carotenoids such as echinenone and β-carotene, which function as antioxidants and contribute to coloration. It also contains polyunsaturated fatty acids, including eicosapentaenoic acid (EPA), beneficial for cardiovascular health. Additionally, sea urchins produce naphthoquinone pigments such as spinochromes, which have demonstrated antimicrobial and antioxidant properties in laboratory studies. While generally safe when fresh, the species can bioaccumulate marine toxins depending on local environmental conditions, posing potential food safety risks if harvested from contaminated waters.