Please
Do Not Collect
Live Sand Dollars
Most visitors to the beach do not realize that taking live sand dollars threatens the species and is in fact
illegal in many parts of the United States. Unfortunately, most are taken by beachgoers during the summer
months when sand dollars are reproducing. So many sand dollars have been taken from Tybee Beach that the
average size has decreased in comparison to populations on Georgia’s other barrier islands.
If you plan on beachcombing, please help to conserve local populations by only collecting white shells.
Scientific name: Mellita isometra
Common name: Five-slotted Sand Dollar or Keyhole Urchin
Phylum: Echinodermata which means “spiny skinned”.
Size: Round, flat, & growing to about 100 mm in diameter.
Color (living): Purple & velvety due to tiny spines & tube feet that are used in respiration, feeding & movement.
Color (non-living): White test (shell), without spines and tube feet.
Habitat: Found primarily on the beach margin and thus susceptible to collection pressures.
Diet: Microscopic diatoms and detritus.
Reproduction: Gametes are released into the water where the larvae swim for a period before metamorphosing.
Association: Small crabs (Dissodactylus mellitae) are ectosymbionts (i.e. they live on the surface of sand dollars).
Predators: Fish, crabs, whelks, seastars, birds.
Other Threats: Storms, high temperatures during low tide, and low food abundance during the summer months.
Human Threats: Pollution, dredging, beach renourishment, trawling fisheries, and the ornamental trade.