Dear Gary, Dennis & Conchologists,


I'm just back from a 7 day diving trip in the north of Cebu with
Gabriella Raybaudii, Scott Jordan, Gina, Sheila Tagaro, Philippe and
Mona. We were 9 divers in all and made an average of 3 - 4 dives a day.

During that trip, Scott asked me how come a Cypraea onyx costs
virtually nothing while we only can dive one to five on a dive, most
often none. (average this means 11 man-hour on the bottom, so one C.
onyx takes about 40 hours to find, even in it's habitat).

The answer is easy: 500 divers each day take shells as a by-catch of
fish and they spend 5 hours in the water a day. If 25 of them find a
C. onyx, this means that 725 pieces will come to the market "a month".
The market cannot absorb that as it is very small, so the price drops.
This is going on for about 60 years by now, don't worry there are many
tens of millions of C. onyx out there. But without knowing the correct
place where to dive, how deep to dive, there is little chance the
average visitor will find this species.

It took me 1450 dives before I know the places where to find
"abundant" species such as C. walkeri, C. onyx and C. boivinii
cuatoni. The quotation in the Philippine books is based on
"Philippine" collecting. The situation may be completely different in
other Island groups in the Indo-Pacific. I remember diving in Kenya
and almost "walking" over Cypraea tigris. I've never found more than 6
tigris in one dive in the Philippines.

The ideal for the Philippine book, which we may consider in later (I
hope) editions, is to mention the rarity as done now (the visitor
thing) and the abundance in collections. A Cypraea guttata sounds then
"rare - common". So does the C. leucodon, "rare - common". A Conus
tisii will be "rare - rare".

Still in this case 30 % of the species at least will sound as "rare -
rare". Bouchet stated that about 30 % of the species collected during
his GIGANTIC expeditions are found by one specimen only. This means,
according to his calculations that in the case of one collected, about
30 000 individuals are around in the region studied. Shells found by
the dozen are there by the millions of course. This does not mean
someone can find them easily. Collecting in the tropical Indo-Pacific
is different from collecting on the rocks in California, or Brittany,
where one can fill "baskets" in hours.

Mabuhay from Mactan island, the Philippines.

Guido T. Poppe
Vice President Conchology, Inc.
Scientific Associate, Malacology Section, Royal Belgian Insitute of
Natural Sciences, Brussels.
Scientific Collaborator to the National Museum of Natural Sciences,
Paris.

Conchology, Inc.
Cebu Light Industrial Park,
Basak, Lapu-Lapu City,
Cebu, Philippines 6015

Phone #: +63 32 495 9990
Fax #: +63 32 495 9991

Websites: www.conchology.be
                  www.poppe-stamps.com
                   www.poppe-images.com
                   www.mambele.be

Email: [log in to unmask]

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