Sea Urchin Gonads: The Edible Part of Spiny Echinoderm With High Commercial Value

Sea urchin is a kind of seafood served in various forms across several cultures. While its exterior does not look inviting due to its long, pointy spines, it rewards intrepid diners with a silky, briny treat.

Sea urchin lovers describe this spiny animal as "the essence of the sea" and "foie gras of the ocean." Contrary to popular belief, the edible portion of the sea urchin is not its eggs but its gonads - the testicles of the male or the ovaries of the female.

Biological Make-Up of Sea Urchin

Sea urchins refer to spiny, globular echinoderms which belong to the class Echinoidea. About 950 species of sea urchin are distributed on the seabeds of every ocean and could thrive in every zone from the intertidal seashore up to a depth of 5,000 meters.

The sea urchin is a dioecious animal, meaning there are separate male and female sexes. However, male and female sea urchins look alike inside and out, so neither can be distinguished based on their external appearance.

Inside the spiky covering of the sea urchins are the gonads or reproductive organs, which may number from two to five depending on the species. Male sea urchins produce sperm inside the gonads, while females produce eggs in this organ.

The reproduction of sea urchins is carried out by external fertilization. In this process, the females release their eggs while the males release their sperm. When these sex cells meet in the water, they undergo fertilization.

Culinary and Nutritional Value of Sea Urchin Gonads

There are 700 known varieties of sea urchins, and all of them are edible. However, those found in cold waters are the meatiest and safest to harvest since they do not pose the threat of finger pricks or poisoning, which are usually inflicted by tropical varieties.

Sea urchins are considered a delicacy in several parts of the world and are sought for their unique flavor. In Japanese restaurants, this delicacy is known as uni, often served raw, with rice, or tucked into dumplings. It is popularly blended into sauces or spread on crostini in the Mediterranean region. They are called ricci in Italy, where they are usually tossed with pasta, while they have also been included in the Chilean diet for centuries. Sea urchins are also a prized delicacy in the Pacific, Norway, and Alaska.

Although the spines of sea urchins are known to cause painful stings, the animal is rich in protein and dietary fiber. It can also provide minerals such as zinc and beta carotene, which it obtains from its kelp diet. Aside from this, sea urchins are high in vitamins C and A, commonly found in dark, leafy green vegetables and winter squash. Like other fatty fish, such as salmon, this animal is also high in omega-3 fatty acids.

Since sea urchin belongs to the lower group in the food chain, it does not bioaccumulate toxins as apex predators do. Moreover, according to the Natural Resources Defense Council, sea urchins have a low mercury load.