Donax Varibilis aka Coquina mollusks

coquina reefYesterday I stated that one of my New Year’s resolutions was to find out something about a new sea creature or ocean wonder.  Here in Florida, we have these gorgeous soft stones sculptures everywhere that are carved out of coquina rock.  Coquina is a porous sedimentary rock  found in Florida.  It is made up of little mollusks, brachiopods or other invertebrates from the sea.  The particles and bits that make it up have to be at least 2mm in size.  The porous holes come from the ocean’s currents and waves sorting, sifting and layering the little bits in layers.  Coquina is a poorly-cemented limestone that is composed mainly of broken shell debris. It often forms on beaches where wave action segregates shell fragments of similar size.  coquina reef1You will find little shoreline reefs up and down the East Coast of Florida made from these little shells.  This rock is also want many of the government orgs around here use to shore up causeways to break storm waves.

coquina coquina butterflies

This is where my wonder started.  Then yesterday while walking the beach collecting shells, I picked up several tiny, colorful little mollusks.  What are these brightly colored things and why do we see them so much?  When the critter inside has left his home or been eaten, these little shells look lile colorful butterflies.  I find them in purple, pinks, yellow and even blues.  When whole they look like tiny clam like creatures.  That is because they are both bivalve mollusks.  These little creatures have two halves and live in the intertidal section by the shore.  Coquina clams can be found from Virginia to Florida, and as far west as Texas. There are many species.  They will generally be under an 1″ in size.  These are super common in Brevard County area along Cape Canaveral, Cocoa Beach and Melbourne shores.  Yesterday during low tide, we saw thousands of shells.   As the tide starts to come in an the little mollusks get trapped in the gullies where the water doesn’t flow back out, the seagulls and other little shore line birds have a tasty feast. They rely on the swash tides to move them up and down the beach and for food and nutrients as well. Coquinas are most active during the warm summer months when movement is easy and the warm Gulf Stream provides an abundance of energy.Coquina are a extremely common species on most Florida beaches and because of their size are overlooked by shell searchers.  I love to fill little jars of them as they have a nice textured and color variety when you fill a jar.

coquina1Generally they are found in a vertical line along the shore.  When these little clams are exposed by a wave, they can dig very quickly back into the sand.  Empty shells are easily found during low tide.  You can see little lives ones and play with them a bit in the littoral tidal zones which is where you have little pools of water form.    When my son was young, we would often sit in these shallow tidal pools and he would learn, appreciate and play with the tiny fish and coquina mollusks found there.

coquina2Donax Variabilis is the most common species found along Florida shores but there are many species.  They are tiny but edible.  I personally can’t imagine how many you would have to eat to feel full!  Some people use them as decorations, I use them as tropical decorations in my hairband line from Gypsy Rose much the way I use little pearls and swavorski crystals.

So when you are walking along the shoreline, stop and bend over and notice the beauty and color of these little critters.

About daniellesdives

diving enthusiast
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