Seashells of Florida Beaches – Atlantic Bubble

The Atlantic bubble seashell is a common seashell on the beaches of Florida. I have found them here and there on all my beachcombing expeditions. They appear to be more abundant on the west coast of Florida, where I have found them in small bunches. On the east coast, where I do most of my beachcombing, it is rare to find them clustered. Usually you find them scattered up and down the beach.

The sea shells are a round elongated oval shape. They are usually smooth and shiny in mottled browns, running from pale beige to almost chocolate brown. Sometimes they may be a reddish-gray in color. Some may have bands running around them instead of mottling. They have a glossy look which only requires a nice rinse in clean water for the gloss of the shell to come out. The underlying seashell is white to almond colored.

The pale grey looking seashells which have lost much of their luster are shells which have been scoured by windblown sand and bleached by the sun. Even when found in the water, it is probable they spent some time on shore and ended up back in the sea.

The seashells also have a white band at the openings. You can see them in the photo on the seashells that I have turned on their backs. All the Atlantic bubbles have this band but it is more prominent on the larger specimens.

Most of the ones I find are small, not much bigger than a dime, perhaps ½ inch long. According to the various sources on the internet, they can grow up to 1 1/8” (3.8 cm) in length. The largest I found on the beach measured 1 inch long, and I have not found too many at that size. The smaller sizes are much more abundant on the beaches I haunt, suggesting that they die young.

The bubble seashells width is close to ¾ of their length. The ½ inch seashells I measured came out to near 3/8 of an inch wide. This was consistent across all the ones that I measured.

The animal that lives inside of these seashells is known as a gastropod. Gastropods are more commonly known as snails and slugs. They are found both on the land and in the water. They inhabit fresh and salt water, from tiny forest pools to the salty oceans. There are thousands of different kinds of gastropods in over 400 families. The Atlantic Bubble gastropod or sea snail is just one of the many that are found in our oceans.

These gastropods live inside their round elongated seashells. They can extend themselves out of the shells to move and eat, and they can contract themselves completely within the shells when threatened or needing rest. They travel around in the same manner as land snails do, by crawling slowly along, only they crawl along the seafloor and whatever else is under the water.

They live in areas with mud flats and sea grasses using them as both their homelands and hunting grounds. Look for the sea snails in estuaries and near shore grass beds. Look for the seashells on beaches that are downstream from those areas. The Common Atlantic Bubble ranges from North Carolina south to Brazil. They can also be found around Bermuda and in the Gulf of Mexico. Guess that makes it all around the Florida coast.

Like many a critter, they spend most of their time searching for something to eat. They do this while trying to avoid becoming a meal themselves. One protection they have is the colors on their seashells. The mottling and bands of brown makes me think of the camouflage clothing an army soldier uses to try to stay hidden from the enemy.

Another protection they have is the ability to burrow under the mud and sand, thereby taking cover from predators. This ability is especially useful doing low tide.

The Atlantic bubble sea snail is not only a prey species but is itself a predator. It feeds on small mollusks – such as clams, scallops, and oysters. An active night feeder that glides across the surface of the seafloor, it envelops and swallows its prey whole.

As the prey passes down toward the stomach to get digested it is crushed. Strong, shell-like hard plates break up the small mollusks the bubble feeds on.

Bubble marine snails, like many snails, have both male and female reproductive organs. These hermaphrodite gastropods fertilize each other’s eggs internally. Fertilized eggs are laid out in long string like coils of jelly-covered eggs. Each coil can contain thousands of eggs and is usually attached to objects in the area – normally sea grass.

When the eggs hatch the young become part of the plankton stream, drifting around and feeding on smaller stuff. When the survivors are developed enough, they will head to the seafloor and grow into the bubble snails whose seashells we find on our beaches.

This bubble seashell is commonly called the Atlantic bubble. Another name for it is the Common Atlantic Bubble. It has also been called the Striate Bubble. Its formal name is bulla striata umbilicata or bulla striata. It belongs to the gastropod family Bullidae.