Goose Barnacles

While many animals die cruel deaths due to plastic in the marine environment, goose barnacles (Lepas spp.) thrive. In order to reach adulthood and leave their easily-eaten planktonic larval stage behind, goose barnacles have to cement themselves onto floating debris in the ocean. Floating debris used to be rare. Then goose barnacles depended on encounters with wood, pumice, coconuts, sea turtles or whales. Now discarded milk jugs, laundry detergent bottles and flip flops are readily available as rafts for goose barnacles. The more stuff floating in the ocean, the greater the chance of a goose barnacle making it past its larval salad days and to reproductive maturity.

Barnacles are crustaceans like crabs, shrimps and lobsters. Adults develop hard shells that enclose soft body parts. Feather-like appendages called cirri fan out from the shells and grab edible bits from the water. Some barnacles, the ones along the coast on rocks and dock pilings, are sedentary. Goose barnacles attach to floating substrates with their tough, orange stalks and travel on ocean currents. The ride ends when their raft washes ashore.

barnacle goose

You may think the goose barnacle got its name because it resembles a goose, but the story is better than that. In the 12th century, Gerald of Wales, the Archdeacon of Breton, claimed that certain geese did not hatch from eggs like other birds, but hatched from nests of barnacles attached to floating wood. Thus, these geese were considered seafood and could be eaten on fast days. Maybe it was a ploy, but in County Kerry, Ireland, Catholics ate goose on Fridays until the 18th century. Today we have a barnacle named after a goose and a goose named after a barnacle.

Gerald of Wales could have just eaten barnacles. It may not have occurred to him, but they are a delicacy in Spain and Portugal. Simmer goose barnacles in salt water, sauté in olive oil, add lemon, cream and scallions, and you have barnacles fit for a feast-day.

I got to the part of the cooking video where the sizzling barnacles were splashed with sherry before wondering how much plastic a bowl of today’s barnacles might contain. Barnacles are indiscriminate eaters. Their feathery legs pull in anything that’s the right size: zooplankton, detritus, plastic. Plastic that leaks into the ocean eventually fragments into tiny pieces that are too small for a barnacle to attach to but just the right size for a barnacle to eat. And they do eat these fragments. Some of this plastic is excreted, some sheds off as they molt and some plastic remains packaged in succulent flesh until it heads up the food chain in a tasty bowl of barnacles or as a meal for a fish.

barnacle raft

Does eating plastic harm goose barnacles? Based on frequent, personal observations of gaggles of goose barnacles on plastic trash that washes ashore, no. You may think an ocean with more goose barnacles is a good thing. It’s never that simple though. When barnacles cement themselves onto a plastic fishing buoy, they turn the slick, inhospitable buoy into a more livable habitat for other animals. The presence of goose barnacles enables other species, even those that normally stay in the shallow end of the ocean, to climb aboard the buoy and ride. With lots of barnacle-covered plastic traveling the seas, there’s more opportunity for species to travel to new parts of the world. A plastic trash raft in the middle of the Pacific Ocean was found with crabs from the west Pacific as well as species from the east Pacific. These animals would normally be separated by thousands of miles of ocean. More ocean plastic means more misplaced species that could become nuisance exotic species. If exotic species thrive, they can eat more, reproduce faster, outcompete local species and wreak havoc on on the ecosystem.

This is something to think about next time you’re at the beach and come across plastic trash weighed down with goose barnacles. Grab a bag from the BlueTube at the beach. Pick up plastic and throw it away. By depriving goose barnacles of a chance to settle down, you may may prevent an invasion of foreign crabs. Add your bags to the BlueTube so others can do the same. If your beach doesn’t have a BlueTube, sponsor one!