Blistering Barnacles! 10 Amazing Facts About Barnacles for Sailors

Ten Amazing Facts About Barnacles (That Sailors Should Know).

Blistering Barnacles! The bane of many a seafarer, the humble barnacle may be small, but its impact is anything but. By attaching themselves stubbornly to hulls, they increase drag, reduce fuel efficiency, and keep sailors busy with endless scraping and antifouling. In fact, this clingy crustacean is at the heart of a global biofouling problem worth an estimated $120 billion each year.

Yet behind the nuisance lies a surprisingly fascinating creature. Here are ten unusual facts about this tenacious crustacean that every sailor should know.

Barnacle Basics

There are over 1400 species of barnacles around the world. Classed as a crustacean they are related to crabs and lobsters. The barnacle that commonly inhabits the bottom of yachts is the acorn barnacle.
Acorn barnacles attach themselves to rock, sealife and boats by secreting a quick-setting cement. This cement is one of the strongest natural glues science has yet discovered. It has a tensile strength of 5,000 pounds per square inch and an adhesive strength of 22-60 pounds per square inch. This is necessary as they like to inhabit intertidal zones where there is a lot of water movement.

Barnacle Biology

Barnacles have a life expectancy of between 8 and 20 years. Their main predators are the whelk and, of course, the pressure washer!
The acorn barnacle’s shell is made up of six calcium plates surrounding the barnacle in a circle. Then there are four plates that act as doors and slide across the top of the barnacle to protect the barnacle from moisture loss and predators.
Barnacles do grow the more they eat. It is not known how they enlarge their shell. Most probably they use a chemical to dissolve the inner layers whilst new layers are added to the outer shell.
Did you know barnacles are hermaphrodites having both male and female reproductive organs? However, they must cross-fertilise to produce offspring. They have a long, retractable tube that can reach eight times their body length. This is the longest reproductive organ length relative to body size in the animal kingdom. At the end of a mating season, this organ dissolves and a new one is grown for the next season.
Barnacles have no heart. They do, however, have a sinus that performs a similar function to muscles pushing blood through.
Barnacles have no gills. Instead, they absorb oxygen through their legs or cirri which wave around in the water.

From hull to haute cuisine

While most sailors curse barnacles for slowing their boats, in Spain and Portugal the goose barnacle has made the leap from hull to haute cuisine. Known locally as percebes, these prized crustaceans cling to wave-battered Atlantic rocks and are notoriously dangerous to harvest. That risk, combined with their unique flavour, pushes prices up to €200 per kilo. They may not win beauty contests, but on Galician menus they’re considered a salty delicacy – proof that one sailor’s bane is another diner’s banquet.

Barnacles in Culture

American poet A E Stallings wrote a poem about a barnacle:

The Barnacle

The barnacle is rather odd -
It’s not related to the clam
Or limpet. It’s an arthropod,
Though one that doesn’t give a damn.

Cousin to the crab and shrimp,
When larval, it can twitch and swim,
And make decisions- tiny imp
That flits according to its whim.

Once grown, with nothing more to prove
It hunkers down, and will remain
Stuck fast. And once it does not move,
Has no more purpose for a brain.

Its one boast is, it will not budge,
Cemented where it chanced to sink,
Sclerotic, stubborn as a grudge.
Settled, it does not need to think.

So the next time you’re cursing barnacles on your hull, remember there’s more to them than stubborn glue and drag. From billion-dollar industries to Galician delicacies, these little crustaceans punch well above their weight. No wonder Captain Haddock made “Blistering Barnacles!” his trademark outburst – few things in sailing life are quite so sticky, stubborn, and unforgettable.