Large bivalve of coast of Paleros, Greece

[iamasmith]

Hi, I recently completed my PADI Open Water course in Paleros, Greece where I saw a large bivalve that appeared to be quite prolific across the dive sites there. The instructor said that it was a Giant Clam but it definitely isn't - it isn't remotely clam like.

This thing has a FLAT shell and seems to vary in sizes up to about 3ft tall and 1ft wide. The first one I saw I mistook for a discarded toilet seat until I got close.

When you get close you find that the top of the thing is open about 1" and there is an array fleshy filters that the creature seems to filter water through right at the edge of the opening.

The thing is greyish to olive green btw.

Any ideas?

(1) How big is the critter?

up to 3ft tall and 1ft wide?

(2) Where in the world is the critter?

Paleros Greece, I first saw it at the St. Nicholas dive site.

(3) What sort of habitat (reef, wreck, sand, rubble etc) is the critter in?

Close to reef, protruding from sea grass.

(4) How deep is the critter?

~8m

(5) What time of day (or night) did you see the critter?

~10am

(6) Any observed behavior of the critter...

Just does what a stationary bivalve does.

(7) If the locals have a common name for the critter, what is it?

Don't know, was thrown by the instructor's name of Giant Clam and didn't ask a local

 

[mislav]

Still sounds like a clam to me. Hard to tell from your description, though. My guess is it was Pinna Nobilis. Did it look somewhat like this?

 

[iamasmith]

Spot on!, that's the beasty, thank Mislav ^^

And having googled for Pinnna Nobilis it's really interesting to hear that this creature was fished to near extinction because it is the source of 'sea silk' (from the Byssus which they use to anchor themselves).

Sea silk - Wikipedia, the free encyclopedia