Whelks: Shelled Predators
W
By Jane Ellis
helks have inhabited
the South Carolina
coast for over 30
million years.
Surprisingly they are carnivorous—
feasting on oysters, clams, and other
bivalves using the tip of their shell and a
muscular foot to wedge their proboscis
(with mouth at the end) into the shells
of prey.
Most research indicates that whelks
begin their lives as males and later
develop into females as they grow older.
So most likely the large whelks you find
on the beach will be female. Females
lay eggs in cases, sometimes called
“Mermaids’ Necklaces,” consisting of
flattened capsules each containing from
0 to 100 eggs and connected by a tough
cord or string that can be over 0.3 of a
meter (one foot) in length.
Whelks are born fully formed but tiny
(less than four millimeters) and grow
slowly. It may take from four to six years
to reach maturity. They can live for up
to 12 years or longer.
Whelks grow by extending their shell
around a central “columella” producing
whorls. The whelk’s soft body is found
in the last and largest whorl. An oval
“operculum” covers the top of the foot
and provides protection when the
animal retreats into its shell.
The most common whelk found on
Kiawah is the knobbed whelk (Busycon
carica). It lives buried in intertidal
zones and often covering oyster and
clam beds in estuaries. This large (1022 centimeter, or four to nine inches)
whelk has striations extending the
length of the shell and prominent knobs
that line the top of the whorls. The shell
opens to the right side (dextral) when
you hold it in your hand with the top
(apex) of the whorls pointing up. The
large glossy opening ranges in color
from yellow to brick red.
Not as common are the thinnershelled channeled whelks (Busycotypus
canaliculatus). These large pear-shaped
predatory whelks have shell whorls
with small beads instead of knobs. The
lightning whelk (Busycon sinistrum),
rarely found on Kiawah, looks similar
to the knobbed whelk but normally has
counter-clockwise shell spiraling and a
left-handed (sinistral) opening.
The smaller pear whelk (Busycotypus
spiratus) has reportedly been found
here but is extremely rare. It has a thin
shell similar to the channeled whelk
with high, smooth, rounded spirals
with no knobs or beads and a large
right-handed opening.
Like conchs, certain species of
whelks have been used as food in salads,
sushi, fritters, and chowders. There is
an active whelk trawling fishery off
the South Carolina coast regulated by
South Carolina Department of Natural
Resources (SCDNR.)
Much more research is needed to
describe these species’ life histories,
movements, and populations. Whelks
are important components of our
biotic community and this information
could be used to better understand the
dynamics and health of Kiawah’s critical
estuary ecosystems. NK
Whelk eggs by Jack Kotz
Whelk with crab by Pamela Cohen
Knobbed whelk by Pamela Cohen
Above: Knobbed whelk by Pamela Cohen
Background: Knobbed whelk by Jack Kotz
5