TYBEE’S WHELKS
One of the best treasures to find on Tybee’s beach is a nice Whelk shell. It
doesn’t matter if it’s big or small, finding a good one is exciting. Depending
on how “fresh” they are, or where they have spent some time buried in the
bottom, Tybee Whelk shells come in a variety of colors. The size depends
on the Whelk’s age when it died. The species will determine its shape and
features.
Whelks are big marine snails, and often are called Conchs. Whelks are
harvested around here, mostly during the winter, and when for sale in the
seafood market, they are usually labeled as Conchs. Some folks want to
distinguish the two by what they eat (Whelks as predators, and Conchs as
herbivores), but there are exceptions to this generalization, so I don’t get
upset with anybody calling any big marine snail a “Conch.”
A Whelk’s shell is part of its body. It doesn’t make new shells or molt
or change shells as it grows. Instead, it gradually grows its existing shell
(that it has when it hatches out of its egg case) by adding new material to
the outer edge of its shell so that it increases in size, spiraling around and
down its existing shell whorls. It makes this hard shell with calcium that it
extracts from the dissolved calcium in seawater.
A live Whelk has a large muscular “foot” that extends out of the shell
opening, and it uses this foot for burrowing around in the sand or gliding
over the bottom to search for food. When we find live Whelks during our
Tybee Beach Ecology Trips, folks are surprised to realize how much slime
they make. Producing this slime aids the Whelk when plowing through the
sandy bottom.
Along with an occasional small Pear or Fig Whelk that we see infrequently
around here, we have three species of Whelks that can grow large shells
10 TYBEE BEACHCOMBER | MARCH 2020
and that we find most commonly on Tybee. Fortunately, for people who care
about identifying things, these three are easy to tell apart. The Channeled
Whelk has a fairly smooth outline. Its shell is thinner, lighter, and a bit more
fragile than the shell of the other two. It gets its name from the thin groove
or “channel” that spirals around the top of its shell. Our heaviest and
thickest-shelled Whelk is the Knobbed Whelk. It has large pointy “knobs”
that extend outward from the top of its shell. The Knobbed Whelk is the
official state seashell for Georgia. Looking similar to the Knobbed Whelk
is the third species, the Lightning Whelk. It also has some knobs, but the
unique characteristic of the Lightning Whelk is that it grows backward from
most other snails, so it’s opening (where the body extends out) is on the
left when you hold the shell in your hand and look at it. With our recent
beach renourishment we are seeing plenty of good Whelk shells showing
up on Tybee!
Dr. Joe Richardson (Ph.D. Marine Sciences) is a retired marine science
professor with 40 years of research and teaching experience along GA, the
southeastern coast and Bahamas. Besides research, he conducts Tybee
Beach Ecology Trips (www.TybeeBeachEcology.com)
Beach Walks
with Dr. Joe
By Dr. Joe Richardson
/(www.TybeeBeachEcology.com)