Captain Al called the other day with the news that there was a Florida Horse Conch feeding at the low tide watermark near the ferry dock.   We used to have one of those in the touch tank, but it was released (along with all the other creatures in the tanks) in advance of a hurricane in a previous summer.  This one was actually too far out of reach to be an easy addition to the tank, but it was beautiful to watch cruising the edges of the oyster bed. The conch, pleuroplaca gigantea, is the largest gastropod in our waters.  It eats other univalves (banded tulips, knobbed whelks), and bivalves like pen shells.  Here, it seems to be eating an oyster.

According to enature.com,

It attacks gastropods by firmly holding on to the victim’s operculum, preventing it from closing the aperture; the conch then inserts its proboscis and eats the soft parts of the prey.

They cruise the sandy, weedy, or muddy bottoms of the tidal flats, searching for prey.  Adults can reach 24″; most of the live ones we may find will be less mature 4-6 inch specimens.   The larger ones prefer deeper water.  Although beautiful white shells can occasionally be found on our beaches, live horse conchs are covered with a dark brown periostracum that makes them seem darker.  The shell is the state shell of Florida.

They produce distinctively shaped egg capsules.  The egg capsules, which are anchored in sand,  contain many eggs.  You might find them on our beaches either as individual cones or a larger mass of cones.  They are made of translucent protein, like many other mollusk egg cases on the beach.