Bay Mouth Bar is a series of sand bars and seagrass beds at the mouth of Alligator Harbor. For just a few days a month, the tide is low enough for it to be exposed for a couple of hours. When that happens, you can see an incredible diversity of life, including more predatory snails than anywhere else in the world. That’s what attracted Dr. Robert Paine to the area in the late 1950’s, as he was forming his ideas about keystone species and food webs. More recently, Dr. David Kimbro and his lab have repeated surveys and found that there have been a few changes in the last fifty years. His doctoral student, Tanya Rogers, is conducting further research into whether the removal of one of Bay Mouth Bar’s top predators played a role in these changes.
Turtle Grass (Thalassia testudinum)
Turtle grass is Florida’s most important seagrass species for habitat formation. Click to expand
Seagrass beds are one of the world’s most efficient carbon sinks.
In the winter, turtle grass blades slough off, landing in mats along the shore called seagrass wrack.
Shoal Grass (Halodule wrightii)
Shoal grass is another of the dominant seagrass species in Florida. Click to expand.
Manatee Grass (Syringodium filiforme)
Manatee grass is commonly found in mixed seagrass beds. Click to expand.
Not a true conch, this large snail is a predator in the lower intertidal and subtidal zones. It feeds on other gastropods, such as lightning whelks and tulip snails, as well as pen shells. The horse conch is the official state seashell of the state of Florida.
The horse conch is the largest predatory snail in Florida waters. It places the bulk of its body on the operculum of the prey snail, preventing the prey from being able to withdraw inside its shell. The horse conch then uses its relatively large proboscis to consume the prey’s flesh.
Tulip (Fasciolaria tulipa) also known as the True Tulip
Tulips were once a primary predator of the Bay Mouth Bar ecosystem, second only to the horse conch. Click to expand
Read more about an experiment being conducted by Tanya Rogers on the loss of predatory diversity on Bay Mouth Bar here.
Banded Tulip (Fasciolaria hunteria)
The Banded Tulip is a predator snail that feeds on a variety of prey. Click to expand
Lace Murex (Murex florifer)
The Murex is one of the predatory snails that has disappeared from Bay Mouth Bar. Click to expand.
Moon Snail (Polinices dulpicatus)
Polinices burrows in the sand flats, looking for its prey. Click to expand
Pear Whelk (Busycon spiratum)
Pear whelks feed on bivalves and small snails, such as moon snails and turban snails. Click to expand
White Baby Ear (Sinum perspectivum)
The White Baby Ear is a drilling predator that feeds on bivalves. Click to expand
Other Gastropods (Snails)
Bruised Nassa (Nassarius vibex) also known as the Eastern Nassa
These scavengers are generally known as “mud snails”. Click to expand
Gulf Oyster Drill (Urosalpinx perrugata)
Urosalpinx are drilling predators, feeding on bivalves and barnacles. Click to expand
Common Atlantic Marginella (Prunum apicinum)
Bay Scallop (Argopecten irradians)
In the summer months, scalloping is a common recreational activity along Florida’s Gulf coast. Click to expand
Pen Shell (Atrina sp.)
The largest clam on Bay Mouth Bar, it is the only bivalve consumed by horse conchs. Click to expand.
Southern Quahog (Mercenaria campechiensis)
The southern quahog is closely related to the northern quahog (Mercenaria mercenaria), which is also known as the hard clam. Click to expand
Sunray Venus (Macrocallista nimbosa)
Click to expand