Eastern Lamp Mussels are
freshwater mussels living in streams and rivers. They live
in gravel and sand on the bottom. Like most freshwater
mussels, the Eastern Lamp Mussel is in trouble. Populations
are declining. While this mussel is not on the Endangered
Species list in Virginia, it is considered a "Special
Concern" species.
North Carolina Atlas of
Freshwater Mussels
North Carolina Atlas of
Freshwater Mussels
Eastern Lamp Mussels have
a long, oval-shaped shell. They are brown on the outside
with dark greenish-black rays. Inside, the shells are
pinkish. All the pictures on this page show only the shells.
A mussel has soft inside parts as well (think of when you've
seen the insides of a clam or oyster). An important body
part of a mussel is the foot. A mussel's foot is not like
your foot. It is a long, muscular body part which can stick
out of the shell. A mussel uses its foot to move.
A mussel can drag itself
over the sandy bottom by pulling with its foot, much like an
inchworm moves. You can often see "trails" that mussels
leave when they move. They also use their foot to burrow
down into the bottom.
Eastern Lamp Mussels pump
water through their bodies at all times. This is how they
breathe and eat. They eat detritus
(tiny bits of dead plant and animal matter in the water) and
plankton
(living plant and animal matter, such as algae
and bacteria).
All the mussels' food is tiny. You need a microscope to see
it.
Copyright, Illinois
Natural History Survey
Eastern Lamp Mussels
breed
in the Winter. Male mussels release tiny cells called spermatozoa
into the water. Female mussels "breathe" the spermatozoa into their
bodies. Tiny mussel larvae,
called "glochidia" grow in the female's body for a year. When they
are old enough, in Spring or early Summer, the mother mussel sticks
them outside her shell on a soft part of her body, called the
mantle.
With Eastern Lamp Mussels, the
female's mantle looks a lot like a small fish. It even has
"eyespots." The female waves her mantle so it looks like a
minnow
swimming in the water. Remember, all of her young glochidia are on
the mantle. To see a video of the Eastern Lamp Mussel's relative, the
Broken-rays Mussel, with mantle imitating a fish, click the link
below:
Broken-rays
Mussel
(Video by Dr. Bill Roston,
Southwest Missouri State University)
What happens next is quite
amazing. A fish will come by, see the phony minnow, and eat it. The
female mussel wants this to happen, because without a fish, her young
glochidia will die. The glochidia, instead of getting swallowed by
the fish, attach themselves to the fish's gills
by snapping down with their shells.
Glochidia live in the fish's gills
for about a month. We don't think they eat from the fish or hurt the
fish at all. They just use the fish as a place to change into an
adult
mussel. Eastern Lamp Mussel glochidia have to attach to the right
kind of fish. If they attach to the wrong kind of fish, the glochidia
will not survive. Some fish which are good hosts
of Eastern Lamp Mussels are Bluegill, Largemouth Bass, Smallmouth
Bass, and Longear Sunfish.
Once the glochidia have changed
into adult Eastern Lamp Mussels, they drop off the fish and sink to
the bottom of the stream or river. Here they will live the rest of
their lives. Eastern Lamp Mussels can live over 30 years.
Mussels are an important part of
the food web. By filtering nutrients
and other items which might pollute the water through their bodies,
they change its form into something other animals can use.
Predators
of mussels include muskrats, raccoons, catfish, herons, and
ducks.
Copyright, Anthony
Ricciardi
One of the reasons
Eastern Lamp Mussels are not doing well, is because of the
Zebra Mussel. This smaller mussel was introduced
from Asia and is taking over our native
mussels.
Zebra Mussels attach
themselves to Eastern Lamp Mussels, and other mussels, and
slowly block the water flow so that they cannot breathe or
eat.
Zebra Mussels also breed
rapidly, making it difficult to control them. They have not
been found in Northern Virginia waters yet, but scientists
believe it is only a matter of time before they spread from
other states.
Eastern Lamp Mussels, like most of
our freshwater mussels, are edible, but you are not supposed to eat
them. Scientists are working hard to try to find ways to save our
freshwater mussels, including the Eastern Lamp Mussel, before they
are all gone. Besides the Zebra Mussel, pollution, erosion,
and dam-building all hurt the Eastern Lamp Mussel. In the past,
people used mussel shells to make buttons, but now they make them
from plastic.
A problem mussels have today,
though, is the Japanese pearl market. To make pearls, they put tiny
bits of ground up shell (from mussels) into oysters in Japan. The
oysters make a pearl around the tiny shell piece. Some people take
mussels from America and send them illegally to Japan.
Mussels help people as a pollution
indicator. This means that scientists can study mussels from a stream
or river and learn how polluted it is. This information will help the
mussels and other animals that live in the water.
