Thousands Washed Ashore
On December 6, 2019, residents of Drakes Beach, California, discovered an unusual sight—thousands of pink, wriggling marine worms covering the shore. These creatures, known as Urechis unicinctus, are commonly referred to as “fat innkeeper worms” or “penis fish” due to their burrowing behavior and distinctive appearance. Recent storms uprooted them from their underground burrows, leaving Drakes Beach, about 50 miles north of San Francisco, covered in the creatures.
A Storm Unearthed the Buried Worms
The worms typically live hidden beneath the sand in U-shaped burrows extending several feet long. However, a powerful storm disturbed the seabed, washing them ashore in massive numbers. Beachgoers, unfamiliar with their appearance, were surprised by the sudden influx of these unusual marine animals. Biologist Ivan Parr noted that their shape is ideal for burrowing, and fossil evidence suggests that these creatures have existed for over 300 million years, with some living up to 25 years.
A Common Delicacy in East Asia
Urechis unicinctus is commonly eaten in South Korea, China, and Japan, where it is served raw or grilled. In Korea, it is known as gaebul, often enjoyed with dipping sauces. The worm’s mild, chewy texture makes it a sought-after seafood item in coastal markets. The species found in East Asia is regularly harvested and sold in fish markets.
Nature’s Efficient Tunnel Digger
These worms play a crucial role in marine ecosystems. By burrowing in sand, they create habitats for small fish and crustaceans, which often share their tunnels. This is where their more polite nickname—innkeeper worm—comes from, as their burrows provide shelter for other sea creatures. Several species, including fish, sharks, and otters, also feed on these worms, making them an important part of the food chain. Despite their unusual appearance, they contribute significantly to ocean biodiversity.