Blisterin’ Barnacles

The barnacle is one of many things I was encountering in abundance on rocky shores and knew almost nothing about. As my rockpool-hopping adventures continued, I was inspired to find out as much as I could about the varied inhabitants of the Cornish coastline, especially life as easily overlooked as barnacles. Here are a few fun barnacle-facts:

• A barnacle is an arthropod, an invertebrate with an external skeleton (exoskeleton), and is closely related to crabs and lobsters.
• Once attached to a suitable location, the barnacle is in place for life. Completely immobile, it is only going to move if  predated or perhaps shoved out of the way by an inconsiderate limpet.

Acorn barnacles… and an inconsiderate limpet perhaps?

• We will mostly encounter barnacles closed up and preserving moisture in intertidal zones and rockpools. However, when feeding, their legs appear, wafting in the surrounding water to catch micro-organisms or detritus.
• While on the subject of feeding… one species, the goose barnacle, is also something of a delicacy in Portugal and Spain.
• The majority of barnacles are hermaphrodites, having both male and female reproductive organs. Self-fertilisation is possible, but rare. Instead, barnacles will most often reach out to neighbours to reproduce.

And the final factoid:

• They can also make rather splendid hats, as this shore crab kindly demonstrates:

  

  Shore crab with a barnacle hat.