Barnacles are crustaceans, related to crabs and shrimp, that live their adult lives permanently fixed to hard surfaces in the marine environment, most commonly the intertidal zone. Their survival in this harsh habitat is largely due to their formidable defense: a hard, cone-shaped shell made of calcareous plates. When the tide recedes, they seal themselves inside this fortress by closing the operculum, movable plates at the top, allowing them to retain moisture and wait out the exposure. This armored existence challenges predators, requiring specialized techniques to breach the shell and access the soft body.
Specialized Marine Predators
Predators that hunt barnacles while fully submerged often employ methods designed to dismantle the calcified shell. Carnivorous sea snails, such as whelks, are among the most common marine threats. These gastropods use their radula—a tongue-like organ with rows of tiny teeth—to slowly drill a microscopic hole through the barnacle’s calcareous wall. Once the shell is breached, the whelk inserts its proboscis to consume the soft tissue within.
Starfish, such as the ochre sea star, use an approach that exploits the barnacle’s structure. The starfish maneuvers its central mouth over the barnacle and uses its hundreds of tube feet to generate suction and force, prying the operculum plates apart. The starfish then everts its stomach into the shell cavity to digest the barnacle’s body. Other predators like certain crabs and fish use brute force, possessing strong claws or crushing jaws capable of pulverizing the entire shell to reach the meat.
Coastal and Avian Foragers
When the tide retreats, barnacles are exposed to hunters that utilize the low-tide environment for foraging. Shorebirds, such as the Eurasian oystercatcher, are highly adapted to this feeding strategy. They use their long, orange, chisel-shaped beaks to deliver forceful blows to the barnacle’s shell. These birds may hammer through the side of the shell or use a twisting motion to pry open the plates, accessing the soft body before the barnacle can fully seal its operculum.
Mammals that frequent the coast also include barnacles in their diet, often scraping large clusters off the rocks. Bears in the Salish Sea region are known to forage along the shoreline and consume barnacles, alongside mussels and crabs. North American river otters, which are adept at utilizing marine prey bases, may also opportunistically consume barnacles when foraging in the intertidal zone. These predators rely less on specialized tools and more on strength and leverage to detach or crush the cluster.
Barnacles as Human Cuisine
Humans also consume barnacles. The most famous of these is the gooseneck barnacle (Pollicipes pollicipes), known as percebes in Spain and Portugal. These stalked barnacles are highly prized for their unique, briny flavor, often described as a cross between lobster and clam. They are typically boiled in seawater and served simply, with the meat extracted from the leathery stalk.
The high price of percebes is directly related to the extreme danger involved in their harvest. Harvesters must risk their lives collecting them from wave-battered rocks in regions like Spain’s Costa da Morte, where the rough Atlantic surf makes the barnacles grow stronger. Other edible species include the Chilean giant barnacle (Austromegabalanus psittacus), called picoroco, and the Japanese goose barnacle (Capitulum mitella).