Gooseneck Barnacles: Rare Delicacy or Dinosaur Feet?

A random piece of what was once a jerry can comes floating on a wave with the strangest creatures attached to it. They grow in clusters, each with a short, fleshy stalk and a body that looks like several flat shell fragments fused together. The edges on some of them are sharp and look like they could give a nasty cut if not handled carefully. Where each plate meets, there is a tinge of orange along the seams, adding just a bit of colour to this strange creature. They are there on a plastic bottle, on a rotting branch, and even on a PVC pipe — they seem to grow on just about anything.

Goose (or gooseneck) barnacles are small sea creatures. They are stalked barnacles and, much like regular barnacles, are related to the more commonly seen and consumed crustaceans like crabs, lobsters, and prawns. Usually found growing in clusters, they are anchored to a hard surface by a leathery stalk called the peduncle. Depending on the species, this peduncle can be short or grow up to 80 cm in length, and varies in colour from orange to dark brown and black. The actual body of the goose barnacle, called the capitulum, is a somewhat tapered structure made up of shell plates — the number, colour, texture, and size of which varies across species. In some species, these plates are smooth, while they are ornamented or striated in others.

Like barnacles, goose barnacles are filter feeders — they sieve through seawater with feathery appendages called cirri that capture plankton (microscopic animals and plants), and sometimes tiny crustaceans, and withdraw with them into the capitulum.

Found along most coastlines across the world, goose barnacles primarily grow in rocky intertidal zones on top of various substrates ranging from rocks to mussels. As filter feeders, they need a steady flow of water rich in nutrients and plankton, making the intertidal zone perfect for their habitation. They are also found on flotsam, ropes, hulls of ships, floating wood, and, more rarely, on turtle shells and, in one case, even on a crocodile. The “glue” or substance with which they attach themselves to rocks is so durable and strong that it has been studied for its potential for medical use.

Harvesting them is risky business, as fishers must navigate tides and swells to reach the shallow rocky intertidal zone, navigate sharp rocks, and manually pick them out. This has resulted in them being among the most expensive seafood in the world. Historically, goose barnacles have been manually harvested. Fishers are severely limited by the tides, weather, and wave action — all of which pose several risks — while ensuring gooseneck barnacles are picked as undamaged as possible and have the fleshy stalk intact. Owing to the increasing demand for goose barnacles as a delicacy, their numbers along some coasts are declining, driving up their price even further. Depending on the location and time of year, in parts of Europe, one kilogram of goose barnacles can apparently fetch as much as 200 euros. In Spain and Portugal, the predominantly harvested species, Pollicipes pollicipes (leaf barnacle), called percebes, is considered a rare delicacy.

Goose barnacles are hermaphrodites, i.e., animals with both female and male reproductive systems. They can take on the role of female or male during reproduction. Some goose barnacle species live up to 25-30 years, with adults laying several thousand eggs every year of their adult life. As with other animals with similar reproductive strategies, many of these eggs don’t survive, and most of those that develop into larvae are preyed upon. While this process is just how nature takes its course, ultimately, these goose barnacles cannot revive numbers fast enough to meet the ever-growing market demand, and their numbers are declining.

Goose, gooseneck, or stalked barnacles owe their name to a myth that dates back centuries. The origin involves goose barnacles (one of the Pollicipes spp.) and barnacle geese (Branta leucopsis). Back when migration was poorly understood, people observing adult barnacle geese on British shores thought they hatched from odd-looking, stalked eggs on the rocky shores that resembled the geese in shape and colour. Never having seen any juveniles or young ones of these migrant birds, people believed that these claw-like “eggs” hatched into young goslings suspended by their beaks until they grew big enough to fall into the sea and emerge as adults. This assumption was supported by the now-discarded theory of spontaneous generation, which proposed that living creatures could spontaneously and regularly arise from non-living matter. It was believed that slime gave rise to oysters, rocks produced barnacles, and geese could arise from goose barnacles.

Another less elaborate theory suggests that the gooseneck barnacles are named so because of the likeness of the leathery stalks to a goose’s neck.

The similarity of shape and colour between certain species of goose barnacles and barnacle geese certainly played a crucial role in the confusion, and interestingly, it has persisted in their names. The English names of both animals (barnacle goose and goose barnacle), as well as the scientific name of a few species of goose barnacles still reflect that (like Lepas anserifera where anser in Latin translates to goose, or Lepas anatifera, where anatis in Latin means duck).

To many, the goose barnacle looks like dinosaur or dragon toes. Googling “dinosaur toe barnacle” results in images of Pollicipes spp. and videos talking about expensive food that looks like dinosaur feet — highlighting the two key properties associated with goose barnacles — food and appearance. However, resemblance to dinosaur feet aside, goose barnacles are not the most peculiar-looking marine creatures to be found, and time and exploration could throw up something even more unique.

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