Inside the spiky test are five corals of roe, sometimes called tongues—the sea urchin’s wobbly gonads. Karoline O.A. Pettersen Sea urchins with their skin and spines removed. Jennifer Steen ...

Considered a delicacy in several parts of the world, sea urchin, or uni in Japanese, is prized for its unique flavor. But the cost of the gonads — the orange tongues found inside an urchin ...