Barnacles Are Related To Crabs, Oysters

Barnacles are frequently seen on solid stationary fixtures such as dock pilings.

By Les Harrison
Wakulla County Extension Director

The arrival of March, with its lengthening days and warmer temperatures, has many residents of Wakulla County fixated on the upcoming summer months.

One of the many advantages of living in the Big Bend area are the numerous choices for summer activities.

Chief among the many entertaining options for spending pastime hours are those which center on the Gulf of Mexico. There is swimming, snorkeling, diving, boating, skiing, and many more ways to enjoy the idle hours in this agreeable setting.

As with any natural environment, a healthy respect for the creatures which reside there must maintained. The salty warm water can obscure some problems for the careless visitor.

While the public perception of marine danger usually conjures an image of a toothy, leering denizen of the deep, the truth is much different. Some of the most common creatures are the most oft cited as inflicting injury on thoughtless human trespassers.

Barnacles are one of those frequently overlooked creatures. The oblivious swimmer or fisherman who contacts their sharp and jagged outer shell usually leaves worse for the wear.

Related to crabs and lobsters, these animals are commonly found in shallow waters which advance and retreat with the tides. Barnacles affix themselves permanently to hard, dense objects thereby encrusting its surface.

This includes dock pilings, sea walls, riprap, and most other fixed objects left in the water. Occasionally barnacles can be found attached to mobile articles like seashells, bottles and other debris.

Combined with a strong current or substantial wave, people or anything else can experience the abrasive qualities of this marine arthropod. Its rough exterior aside, barnacles are a benign and curious inhabitant of Wakulla County’s coast.

There are currently over a thousand identified barnacle species known worldwide. Those from the super order Cirripedia are most common in local waters.

Barnacles have two larval stages before developing into adulthood.

Once hatched, the initial phase involves growth and development for about six months.

The second larval stage finds the barnacle independent and seeking a lifelong site with all the necessary amenities. This period may last from days to weeks as the barnacle explores its environment while being carried by the currents and tides.

During the second larval stage the tiny barnacle lives on stored nutrients and does not eat. As these resources deplete, the unlucky barnacle may be forced to settle for a less than ideal home site.

When the site is selected, the barnacle literally becomes attached for life. It uses secretions from glands at the base of its head to glue itself upside down to the object.

As they settle in to their new home, they develop protective armor plating. Barnacles continue to build this predator protection throughout life, adding new material to their heavily calcified and rough shells.

To feed, the barnacle extends it feathery feet into the flowing water and filters out plankton delivered by random chance.
Even this seemingly simple and carefree life has some serious complications.

Marauding Whelks, a native gastropod commonly found in the waters off Wakulla County, consider barnacles a top menu choice. They easily grind through the barnacles’ exoskeletons and consume the softer inside parts.

The immobile barnacles can only await their fate. It seems like there is always something out there to spoil summer’s fun.


Posted: March 4, 2016

Category: Coasts & Marine, Natural Resources, Wildlife
Tags: Barnacles, Environment, Extension, Florida, Les Harrison, Natural Resources, Natural Wakulla, Wakulla, Wakulla County, Wakulla County Extension, Wakulla Extension

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