Whelks are the beautiful cone shaped shell that we hold to our ears to hear the ocean.
Knobbed whelks, Busycon carica, are large predatory gastropods. They are large sea snails that can vary in color, size and features depending on their distribution along the coast. Knobbed whelks have been found in both tidal estuaries and deeper waters of the Atlantic coast. They prefer to live in sandy or muddy bottoms and can be found congregated on oyster and clam beds. During winter storms they are known to bury themselves and go dormant.
Knobbed whelks reach up to nine inches in length.
When looking at a whelk, the very top peak of the shell is where the creature began. From the top, whelks create turns (known as whorls) as they evolve. The final whorl, or body whorl, is the larges. This is the area that creates the opening into which the snail retreats. Their withdrawing aperture is on its right side. They can range in color from light orange or yellow all the way to brick red.
The whelk’s specific coastal habitat determines knob length, color and size. Diet and natural camouflage are both factors in shell differentials. All whelks have a hard horny plate known as an operculum. This acts as a protective cover for the snail when it retreats into its shell and protects it from predators. This plate is also referred to as the shoe. The operculum attaches to the whelk’s foot. This operculum foot protrudes from the aperture and aids in transportation.
Whelks feed on meat.
They use both their shell, as well as an appendage known as a radula, to eat other hard shell creatures. Whelks will use the lip of their shell to chip at and pry open hard clams and oysters. Once a whelk is able to pry open another bivalve, they use their strong radula to tear away strips of tissue for consumption. Using the lip of their aperture causes chipping and damage, which they must take time to repair.
Knobbed whelks are protandric hermaphrodites.
They start their life as males and turn into females as they get older. Female whelks will lay eggs twice a year, usually when the water temperatures are around 68 Fahrenheit. September to October is their most productive time. They create egg strings that have a series of coin-shaped capsules attached at one end by a rough cord or string-like structure. They can reach lengths of up to one foot. The eggs will hatch within their capsules anywhere between three to 13 months.
By Kathleen McMenamin, Master Naturalist
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