A simple fact is that a or a few collectors can't wipe out a species if mollusk
is one takes
adults and not net the very young in the water or from under the sand in all
locations.

With few exceptions (I suppose) the groups are not in the same location and are
not collectible.
The young floating or in a 'nest', the growing are in deep water or sand and the
adults are in
deep water, shallow sand or shallow grasses.  The older ones - perhaps due to
their weight
are swept closer to the shore or into mossy coral where I often found them.

A extinction would have to be in a habitat - a small loci that they limit
themselves within and a
calamity also at that site or at least 'feeding' the site with water currents. [
Farming runoff that
contains chemicals intended for 'bugs'. Runoff of a mountain that finally cuts
into a vein of
a metallic substance - arsenic, lead, copper and so forth.  A chemical shift can
cause
reproduction to cease or all delicate fry to die.

In the various parts of the world, there are massive floods that wipe an area
(Mississippi & Ohio) or
West Texas  as examples - dumping whatever it washes into the coastal area.
Sometimes
the surge is enough to take shallow water shells deep into the ocean.

So I think mother nature and her power and some of our uses and abuses all aid
into the demise.
Some are just out of luck or they lack planning ability.  Their food supply is
limited and another
moves in that also eats the grass.

Reasons abound.

Martin

--
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net

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