On 11/27/2010 1:56 AM, Doug Stemke wrote:
> Hi Folks.
>
>     Quite by chance I had the opportunity to meet a truly fascinating man.
> Because I don't want any of his personal information to go out on the web,
> I'll simply call him 'Bill'.  Anyway he was a former Geologist with all the
> insight of a good scientists.  Further his work in oil has provided him with
> the means to have the ability to build himself a sailboat, which he too from
> the Bahamas down most of the Lesser Antilles over a two year period.  As a
> diver he took his observational skills down with him.
>
>     The first part I know well, the reefs in the Caribbean are in terrible
> shape.  In most places out side of one location in the Bahamas where he was
> still able to see healthy corals (he rattled off the scientific names of the
> species including the two Stag-horn Corals but I wasn't fast enough to catch
> it) he rarely found more than a few small patch reefs.
>
>      Another things he described were the large living mollusks he saw. The
> several Tritons (Charania) and 'other large mollusks' he saw (non-Strombus)
> all had boring-sponge damage.  While he said that on previous trips he had
> seen this on non-living shells he had never seen it on living specimens
> before.  Also he stated that on his previous trips the large Conch he saw
> (presumably Strombus gigas) were clean, the current living specimens he saw,
> regardless of the island were covered in algae.
>
>      My only personal observations in the Caribbean were in Belize, while I
> saw the same level of coral reef damage the S. gigas I saw (as late as 2000)
> looked pretty healthy.  That was the only large live Mollusk I saw in Belize.
>
>      Anyway, my question with the sponge-damage is that stress related too?
> Do living gastropods normally limit sponge damage but because of stresses
> invite the boring-sponges to do more damage?  I suspect that he may not have
> seen a large enough sample size on either of his trips to really make a case
> for more mollusk damage now than in the past, but I thought it would be
> worth a note to the group.
>
> Thanks.
>
> Doug
>
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Sounds like the reefs are missing the fish that browse algae and sponges
and keep areas clean, including the backs of big shells.  Also the older
the shell the more boring sponge.  Perhaps the population is skewed to
just old shells and no young or healthy rapidly growing members of the
population.  The lack of Parrot Fish allows overgrowth of algae and does
not provide clean spots for new corals to attach and grow.  Keith

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