James,

"...look at Strombus gigas... look at the Tridacnids...  These species were
(and still are) under such high predation..."

I assume you mean collection pressures by man as "high predation."
Actually, if you really look at S. gigas I bet you will find development and
the resultant polution had more to do with its demise than collecting
pressures (whether for food, bait, or tourists).  This thread has gone
around a number of times on Conch-L and someone always mentions the tons
annually harvested in places like Haiti or the Bahamas -- where the S. gigas
is still plentiful.  Yet in Florida, where collecting has been banned, and
despite attempts to repopulate with "farmed" stock, the population has not
come back.  The reasons are probably many and complex; but the bottom line
is, a complete halt to collection has not meant a resurgent population.

Because large numbers of a shell are or were collected does not equal the
reason for its scarcity.  Bob's example of the ubiquitus Cypraea moneta is
the best example of this.  Tons of these small cowries were collected in the
past and they are still sold by the pound for the tourist trade.  Yet this
remains a very common shell.  Extinction is far more complex than most
people realize and it is often too easy to latch onto a single, "sensible"
but unproven reason.

I applaud your efforts to look at this issue, but as an old pysch prof used
to say, "correlation is not causation."  Mankind (pun fully intended) has
certainly developed harvest techniques for just about anything you want to
name way beyond what is reasonable.  Left unchecked we can or soon will be
able to clean out any given species.  This has only recently become the case
with the seas, but ever-vigilant, we strive onward and continue to improve
our methods.  I say this to balance off my earlier statements.  I think it
would be tough to really point to a seashell species and say, "They were
collected into oblivion."  But 50 years from now, that statement may be
something like, "As went the passenger pigeon, so went the so-and-so
seashell."  But today, I think we should look to the environment we are
creating; the effects of which may make over-collecting irrelevant.  Yeah, I
know about dynamiting the reefs and all of that -- but pressures are on in
those areas to halt this practice (effective or not), but who is stopping
the sewage, chemicals, fertilizers, silt, garbage, etc from an ever
increasing population that either flows into the ocean or is hauled out to
sea and dumped.

Soapbox just cracked and before it breaks, I'm outta here.  Didn't mean to
sound preachy (notice, that is not the same as saying I didn't mean to
preach).  Any responses or arguements, please send them to Art Weil.

Tom Eichhorst in New Mexico, USA