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Artwork by: Joann Wheeler, 1999 |
Fast
Facts:
The Latin word "Mya" translates into
"a sea mussel" and "arena" translates into "sand." Maryland
exports roughly 90% of Chesapeake Bay's harvest to New England. An adult soft shell
clam can filter up to four liters of water per hour! |
| Size |
Up to 6 inches. |
| Habitat |
Soft shell clams are found buried in mixtures of sand/mud and
mud/gravel where salinity is reduced by freshwater runoff and seepage. Soft shell clams
can tolerate a variety of salinities (5-30 ppt), which makes them well adapted to estuaries. They can live in areas of low dissolved oxygen for
short periods of time. Soft shell clams can often withstand
below freezing temperatures. |
| Reproduction |
Soft shell clams are capable of reproduction after their first year of life and
reproduce by spawning. Spawning is triggered by the increase in water
temperature. Once the eggs are fertilized, free swimming larvae develop within a few hours.
Despite their free swimming abilities, they are still susceptible to currents, winds and
wave action that can disperse them great distances from the site of fertilization. The
larval period generally takes one to three weeks but is greatly influenced by water
temperature. Larvae metamorph into the juvenile stage and resemble small adults. Juveniles
crawl along the bottom sediments looking for suitable substrates. Once they find a
suitable substrate (good food resources, low predation and low wave action), they dig into
the sediments with their muscular foot. While small, they can re-emerge and search for
other suitable substrates. However, when soft shell clams become larger, the remainder of
their life is spent sessile beneath the sediments. Adults can be buried a foot or
more under the sediments. |
| Feeding |
Like all other bivalves, soft shell clams are filter feeders extracting their
food (e.g., phytoplankton) from the water column. Soft shell clams have
two tubes, called siphons, that work together to strain out food particles from the water
column. Water is pumped through one siphon, passed over the gills where food particles
collect, and pumped out the other siphon. |
| Predators |
Animals that eat soft shell clams are quite numerous and include several species of
crabs including the blue crab (Callinectes sapidus) and
horseshoe crab (Limulus
polyphemus), snails, starfish, fish such as killifishes (Fundulus spp.), and
waterfowl such as black ducks (Anas rubripes). |
| Description |
Soft shell clams have thin brittle shells and a distinguishing leathery tube that
encases their well developed and retractable siphons. The elliptical white shell has a
spoon shaped depression inside the left valve at the hinge, while the other valve has a
projecting tooth that fits into the depression. Soft shell clams can live up to 12 years
in Massachusetts. |
| Other facts: |
When disrupted, soft shell clams eject a spurt of water and withdraw to a safer depth
in the sediments. This squirting behavior has earned them the nickname "piss
clam." |
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