MERMAID’S NECKLACES
By Dr. Joe Richardson
A while back, during a Tybee Beach Ecology Trip, a lady asked me if we ever
find “Mermaid’s Necklaces” on our beach. I had never heard of a Mermaid’s
Necklace, so I asked her what they looked like. As she described them, I
realized that yes, indeed we do see them on Tybee. I had just never heard
that name for them, but I quickly decided that I liked that name! And sure
enough, a few minutes later, we found one.
A Mermaid’s Necklace is actually the tube manufactured by a Plumed Worm.
It’s named that because it has feathery-like gills that extend from each side
of its body near its front end. Plumed Worms live in the sandy bottom, just
offshore from the normal low tide line. As it digs its hole into the sand, it
produces a lot of slime that becomes a paper-like tube or straw, so the worm
can move up and down inside the tube, but sand doesn’t get in.
Even though its tube might extend a few feet into the sand and stick up an
inch or two, the worm doesn’t stop construction with just this papery tube.
The worm will extend out of its tube and catch shells, plant debris, seaweed,
and anything else drifting by, and then attach these objects to the outside
of its tube. So the upper few inches of its tube are reinforced with these
building materials to give it added strength to hold it up into the water above
the bottom. This firm structure sticking up above the bottom also provides
26 TYBEE BEACHCOMBER | JUNE 2018
a surface for drifting seaweed to become attached, and for small animals to
colonize and hide in. These small animals and seaweed then become food
for the Plumed Worm. So the worm not only constructs a chimney for its own
tube, but also produces a food magnet!
Occasionally, the top part of a Plumed Worm’s tube will get torn off, or old
tubes will get washed out of the bottom, and they will get washed up on the
shore. It might look like a small chain of shells, or it might look like a thick
string of plant and seaweed fragments, or it might look like a thin rope of a
combination of these things. The nice ones, that look more like a “Mermaid’s
Necklace,” will be the ones constructed of a bunch of small shells.
During June we will be having some really low tides, and down near the
water line you might just see some of these Mermaid’s Necklaces sticking
out of the sand, in place. Just remember, there is still a Plumed Worm living
down inside! So, only collect ones that have washed ashore. And then enjoy
your new piece of jewelry from the sea!
Dr. Joe Richardson is a retired marine science professor with 35+ years of
research and teaching experience along GA and the southeastern coast and
Bahamas. Besides research, he conducts Tybee Beach Ecology Trips year
round (www.TybeeBeachEcology.com) and frequently posts pictures of what
they are finding on his Tybee Beach Ecology Trips Facebook page.
Beach Walks
with Dr. Joe
/(www.TybeeBeachEcology.com)