Discovering the Delicacy of Sea Urchins: A Culinary Journey

Sea urchins are a unique delicacy discovered from the sea. Originally an Asian food, they have captured the taste buds of people globally with their edible orange flesh nestled inside a thorny outer shell. The Japanese have perfected the cuisine made from sea urchins, creating delicious rice and sushi recipes that highlight their flavor.

What Are Sea Urchins?

A sea urchin is an echinoderm, part of a family of marine invertebrates that includes sea cucumbers, starfish, sand dollars, and crinoids. These fascinating creatures inhabit seabeds, moving around by using their spines as legs and feeding on algae.

Sea Urchins: Unique Facts

Culinary experts describe the taste of sea urchins, known as 'uni' in Japanese, as sweet and salty in an oceanic way. Rocky ocean floors serve as breeding grounds for these intriguing creatures. Their bodies exhibit radial symmetry, a common feature among echinoderms. Once harvested, the sea urchin is split open, revealing the golden yellow gonads inside, which are arranged like petals on a flower. Typically, there are five gonads within a sea urchin. Most often, they are enjoyed raw, especially in sushi dishes in Japan. Playfully referred to as the hedgehogs of the sea, their thorny outer shell justifies this nickname. Interestingly, as sea urchins grow from larvae, they invert themselves, causing their spiky interior to become their outer shell.

Sea Urchins: A Unique Culinary Experience

Sea urchins, or uni, are among the few food items harvested from the wild and eaten raw. They can live for decades, even centuries, if left undisturbed. Moving slowly along the rocky sea bottom, they consume whatever they encounter and grow steadily. Found in oceans worldwide, sea urchins must be handpicked by harvesters due to their delicate nature. In Korea, women scuba divers are traditionally the experts in harvesting uni.

Not everyone appreciates the taste of uni. Its briny aroma and slightly sweet, creamy texture can be an acquired taste. However, many lovers of uni swear by its unique flavor.

Sea urchins consume sea algae, making them an excellent source of omega-3 fatty acids for humans. Uni also contains significant amounts of protein and antioxidants, with most of its fat being unsaturated.

Enjoying Uni: The Popular Sushi Dish

Uni sushi, a popular Japanese dish, is one of the most common ways to enjoy sea urchins. This dish consists of cooked rice wrapped in a sheet of seaweed and topped with raw sea urchin gonads. Sea urchins also feature in salads and are sometimes served in their outer shells, showcasing their unique presentation.

Cultivation Method of Sea Urchins in Coastal Seas

Uni is plentiful in the coastal waters of California. Sea urchins come in both male and female varieties. They release sperm and eggs into the surrounding seawater, where fertilization occurs rapidly. The embryos swim in the ocean for a period, taking on the peculiar shape of a space lander. Once the spiny adult form has developed, they turn themselves inside out. Just before this rapid maturation, the embryo attaches to a rock, resulting in a well-formed sea urchin with spines and numerous tubular feet.

Sea urchins are found in various colors, including green, pink, purple, red, black, and pale yellow. However, not all are suitable for consumption. This marine species is among the most sensitive organisms globally regarding their response to global warming and climate change.

Japan has successfully bred sea urchins on commercial farms. Eggs and spawns are gathered from sea urchins and fertilized in a laboratory environment. Once the embryos hatch, they are grown in artificial tanks until they mature enough to survive independently. During this period, they are fed sea algae. Sea urchins are voracious feeders, consuming large amounts of sea algae. Occasionally, they are kept on the farm for a year or longer before being harvested or released into natural water enclosures for later harvesting.

The Protective Behavior of Sea Urchins

Sea urchins sometimes cover themselves with rocks and other materials as a form of camouflage, helping them survive in the hostile environment of the ocean floor. Predators like wolf eels, triggerfish, putterfish, and parrotfish can break open their shells using strong jaws. Crabs and lobsters also prey upon them, crushing their outer shells with their claws.

California Has A Sea Urchin Problem: Just Eat Them To Solve It

Sea urchins exhibit self-covering behavior under environmental stress. They tend to cover themselves with pieces of rocks and shells. Scientific studies suggest that this covering helps protect them from predators and physical damage from intense sunlight. Additionally, these covering materials can serve as a source of food.

Just as cattle grazing depletes our terrestrial environment, sea urchin grazing impoverishes the marine ecosystem. Sea urchins destroy green algae ecosystems by feeding on them. California is facing a serious problem with sea urchins destroying its environmentally valued kelp forests. According to an article in The Guardian, the population of sea urchins along the Californian coast has surged by 10,000% since 2014. The destruction of kelp forests devastates the entire marine ecosystem, including the fish that rely on them for food. Areas where over 95% of the kelp forest has been wiped out are known as 'urchin barrens', dominated by a vast expanse of sea urchins covering the ground. Scientists have been urging Californians to include sea urchins in their daily diet to help manage their population.

How to Keep Sea Urchins Fresh

Now, let’s share a quick tip on how to keep sea urchins fresh once bought or harvested. They can be kept alive in saltwater for many days. Alternatively, you can cover them in a damp cloth and store them in the fridge.

In conclusion, sea urchins are not only a culinary delight but also a vital part of our marine ecosystem. By understanding their role and enjoying them responsibly, we can contribute to a sustainable future.

References

The Solution to California’s Rampant Sea Urchin Problem is to Eat Them: I Gave it a Try. Vivian Ho, theguardian.com

Sea Urchins Pull Themselves Inside Out To Be Reborn, Deep Look, YouTube.