Hermit crabs can also move shells from somewhat deeper water into shallower
water where wave action can move them onto the beach.  Also, though I've
never read any research on this, it seems to me that molluscivorous fish
could also do this, probably more effectively than crabs.  It is known that
many species of fish swallow live molluscs whole.  It is also known that the
shells of consumed molluscs move through the digestive tract of fish,
emerging at the other end with little or no damage.  In fact, I read
somewhere that gastropods with tight-fitting opercula have even passed
through fish alimentary tracts alive!  And, it is known that some species of
fish move into shallow water at night and out into deeper water during the
day.  So, considering all those known facts, it would seem to me that shells
from relatively deep water might be carried into shallower water and
deposited there by some fish species.  Anyone ever heard of such a thing?

> ----------
> From:         Conchologists List on behalf of [log in to unmask]
> Reply To:     Conchologists List
> Sent:         Friday, March 24, 2006 11:50 AM
> To:   [log in to unmask]
> Subject:      Re: Beacg Shells
>
> O.K., Here's one thought! Unless they are very light and/or pelagic, dead
> shells would have to come from pretty close. Weight would cause them to be
> pretty close to the bottom. Storms could send unusual material up on
> beaches. But I betcha most of what you find dead on a beach would be live
> there at some time.
>      But what do I know.
>          Art
>
>
> --
> PLEASE NOTE: My new, long-term, and correct email address is:
> [log in to unmask] Please update your records!
>
> ---- ronald noseworthy <[log in to unmask]> wrote:
> > Hi, everyone!
> >
> > While I was preparing a database on the mollusks of Jeju
> > Island, I realized that I had a lot of records of dead
> > material from the many beaches on this island.
> >
> > What is the relationship between the dead shells found on
> > beaches and the living populations of those species?  Would
> > the dead material be an accurate record of the living
> > mollusk fauna of the adjacent area?  What exceptions would
> > there be?
> >
> > I have searched the Conch-L archives but found little on
> > this subject.  Any assistance you can offer would be greatly
> > appreciated.
> >
> > All the best from Korea!
> > Ron Noseworthy
> >
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