Diving with Scallops

Lanta Marine Life | Pectinidae

Scallops are a large and varied family of plankton eating filter feeders which are found in all of the world's oceans, including the dive sites around Koh Lanta.

Most species live on the sandy or rubble seafloor and are capable of rapidly swimming short distances. These are known as 'free-living' scallops, however a few species live cemented to rocks or hard coral skeletons, and a few may even attach themselves to soft corals or seagrass.

They have light coloured, symmetrical, fan-shaped shells which radiate from the valve connection and are often fluted. The shell of a scallop consists of two sides or valves, a left valve and a right one. Most species of scallops rest on their right (lower) valve, and as a result this valve is often deeper and more rounded than the left (upper) valve.

Similar to thorny oysters, scallops have a well developed nervous system and have many small, simple, eyes arranged along the edge of their mantles (the soft flesh around the edges of the shell halves). Scallops rely on their simple eyes to detect movement or shadows which could indicate the approach of potential predators.

1 species found on this page:

Iridescent Scallop (Pedum spondyloideum)

Iridescent Scallop

(Pedum spondyloideum)

Pedum spondyloideum @ Koh Haa

The 'iridescent' or 'coral' scallop is found embedded in living hard corals. This bivalve excavate the hard coral to create a cavity for itself and attaching to the coral by strong, silky fibers (byssus threads).

The scallops are provided a safe place to live by the coral, and in return can help protect the coral from attack from predators such as the crown-of-thorns sea star by repeatedly squirting out jets of water.