I could tell that the log had only recently been brought in by a high tide and left high and dry, because the goose barnacles were still intact; their feathery legs were exposed but not dried up.
What is a goose barnacle? As its name suggests, it is an animal closely related to barnacles. Barnacles are in the class of crustaceans, which includes animals with exterior shells and jointed legs such as crabs, shrimp, krill and hermit crabs. In barnacles, the exterior shell is usually made of several plates, which are joined together to form a crater shaped tent in which the animal spends its life standing on its head and kicking its feathery legs into the waves in hopes of filtering out tiny food particles.
Goose barnacles also have the plates to cover their body, and the feathery legs with which to kick and filter food out of the water, but they are shaped like an almond: somewhat flat and elongated. The scientific name for the barnacles, “cirripedia,” refers to those feathery feet: “cirri” = feather, and “pedes” = foot.
The most striking feature of goose barnacles is a long “neck,” a flexible tube with which the animal attaches to a rocky or wooden surface.
When I looked up the goose barnacle, I found some entertaining information worth sharing: In parts of Europe bordering the Atlantic and Greenland Sea, there is a goose called the barnacle goose. It turns out that barnacles actually get their name from this goose!
In medieval times, people noticed that while the geese were common in winter, they were rare in summer and no one saw chicks. While we now know that the geese are migratory and spend the summer along the Arctic coast, a text originating from the year 1187 explained their mysterious absence by a peculiar way of reproduction:
“They are produced from fir timber tossed along the sea, and are at first like gum. Afterwards they hang down by their beaks as if they were a seaweed attached to the timber, and are surrounded by shells in order to grow more freely. Having thus in process of time been clothed with a strong coat of feathers, they either fall into the water or fly freely away into the air.
“They derived their food and growth from the sap of the wood or from the sea, by a secret and most wonderful process of alimentation. I have frequently seen, with my own eyes, more than a thousand of these small bodies of birds, hanging down on the sea-shore from one piece of timber, enclosed in their shells, and already formed.
“They do not breed and lay eggs like other birds, nor do they ever hatch any eggs, nor do they seem to build nests in any corner of the earth.”
Because of this widespread legend about the reproduction of the barnacle goose, the church considered it proper to eat the geese during fasts because their flesh was not born from meat. I did not find information about the consumption of goose barnacles in medieval times, but nowadays goose barnacles are considered a delicacy and highly prized as gourmet seafood in parts of Europe.
Apparently, the stalks contain the edible meat, whereas the shelled part is discarded. If you are inclined to try our local goose barnacles, please keep in mind that contrary to the statement in the old legend that has the goose barnacles living off tree sap, they are indeed marine filter feeders. As such, they may be susceptible to contamination with the algae that cause paralytic shellfish poisoning in humans, a condition that can result in death.
Reading this story made me reflect on how sometimes scientists are confronted with skepticism and disdain for their work. For example, there are many climate change deniers among politicians but very few (if any) among people who have studied the data associated with the cause-effect relationships of climate. If we left the reasoning about the workings of our world to explanations by people who are not educated in what they are writing about, we may have politics based on the information that geese grow out of goose barnacles.
Switgard Duesterloh, Ph.D., is an assistant professor of natural sciences at Kodiak College. She operates the Kodiak Ocean Science Discovery Lab and teaches ocean science to students throughout the Kodiak Island Borough School District.