Tripneustes gratilla is a species of sea urchin in the family Toxopneustidae, commonly known as the collector urchin, white sea urchin, or by various regional names in Indo-Pacific cultures. It is a shallow-water marine echinoderm widely distributed throughout the tropical Indo-Pacific region, including the coasts of East Africa, Southeast Asia, Japan, northern Australia, Micronesia, Polynesia, and Hawai‘i, where it inhabits seagrass beds, coral reefs, and sandy lagoons. The genus name Tripneustes derives from Greek roots meaning “triple breathing”, likely referencing their distinct respiratory structure, while the species epithet gratilla is thought to derive from Latin craticula, meaning “little lattice”, describing the patterned test or spine arrangement.

Historically and in modern practice, Tripneustes gratilla is harvested for its gonads, which are consumed as uni in many coastal cultures. In Japan and parts of Southeast Asia, it is eaten raw in sushi and sashimi preparations; in the Philippines and Pacific Islands, it may be eaten fresh, lightly marinated, or incorporated into seafood dishes; and in Hawai‘i it has traditionally been consumed as a seasonal delicacy. Aquaculture efforts have been undertaken in several regions to stabilize supply and enhance roe quality. It is associated with Japanese, Filipino, Pacific Islander, and other Indo-Pacific coastal cuisines.

The species contains including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), omega-3 fatty acids known for anti-inflammatory and cardioprotective effects; echinochrome A, a polyhydroxylated naphthoquinone pigment with antioxidant and potential cardioprotective properties; ovothiol, a sulfur-containing antioxidant that protects cells from oxidative stress; and carotenoids such as β-carotene and astaxanthin, which contribute to coloration and antioxidant activity. These compounds contribute to its nutritional profile, supporting cardiovascular health and offering antioxidant benefits, while also influencing the flavor and color characteristics valued in culinary applications.