Hypothesis re: Abalone pearl formation

J Marcus

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Hello fellow pearl people!

Recently, Steve Metzler contacted me and put me in touch with Ana Vasilu who is doing research on shell formation at the University of Granada in Spain. We have been corresponding and I have sent samples of shell anomalies to Ana Via Steve. It has caused me to write down some ideas that I have been mulling over. For a few years I have been speculating about the nature of pearl formation in at least some species of haliotis. It's been a matter of putting together some of what I have read about haliotis with observations I have made and speculating as to what this might mean. This applies only to the smaller, more-round or nugget-shaped, free pearls found, to my knowledge, in the area of the mantle in abalones. I have now formed an hypothesis based on these speculations. I have between little and no proof of what I propose in the following, but think that my ideas are quite possibly worthy of serious, scientific investigation. Therefore--I propose the following:
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1. Haliotis, or abalone seem to have very prodigious shell making capacities. It seems to me, for a couple of reasons, that they are able to produce and lay down a lot of shell very quickly both to keep ahead of the many parasites that are constantly riddling and eating away at their shells, and also they both need and have the ability to repair very quickly, punctures and other traumatic shell damage.

2. Along with an ability to produce nacre quickly (I assume) they are also able (again, I assume from my observations) to very quickly produce the protein-based component of their shells--conchiolin--in large quantities. To my limited knowledge, it seems there is no other type of mollusk that has such a prodigious ability. I also assume that there must be an evolutionarily advantageous reason for this.

3. Abalone are hemophiliac. Therefore, it is of primary importance for them to protect themselves from damage or intrusion by predators or parasites that would cause them injury and thus cause them to bleed to death. If such predators or parasites intrude through their shell in such a way that they might cut or other wise do injury to the abalone, then, in evolutionary terms, the survivors would likely be those that had an effective mechanism of defense. I propose that the parasitic invader most likely to cause the need for such defense may well have been one or more of the boring clams or something very like them. In order to bore through the shell of the abalone, the clam has rough, abrasive projections on the outside of it's shell that, when rotated back and forth, wear away at the abalone shell. I assume that the boring clams that parasitize the abalone are not focusing on abalone specifically. I have seen the bore holes of boring clams in a number of materials including wood and even soft sandstone or mud stone. They tend to bore up to several inches into the material. I propose that when the clam finally breaks through to the inside of the abalone shell, it maintains it's attempt to bore and thus, by it's boring action, or even simply by presenting a rough, abrasive surface to the body of the abalone, threatens to cut or abrade the abalone, therefore threatening it's life. It is possible that the survivors had the ability to produce large quantities of conchiolin, which I have read of as being essentially a glue composed of several proteins. After cleaning out several hundred blister pearls, I feel very confident stating that every one of these blisters, where the clam shell is still in place, or even most of them where the clam's shell is missing, and where the mollusk has had time to react to the damage, contains, inside of the blister, a very heavy layer of conchiolin that can be up to two millimeters or more in thickness. The conchiolin usually extends down the sides of the clam shell, effectively, I think, cementing it in place. When it is finished depositing the conchiolin, the abalone will then cover the conchiolin with layers of nacre and more conchiolin, thus walling off the clam.

4. I propose that this very-powerful defense-mechanism, which is capable of producing large amounts of shell material very quickly to protect the mollusk from life-threatening injury, is constantly in a state of high alert and easily set in motion, possibly even by stimuli other than it's intended target. There is a parallel hypothesis that might serve as a model, for which there is a growing body of evidence I understand, in the allergic or histamine response in mammals--including humans, of course. Apparently the histamine system has evolved to defend against parasites larger than bacteria, viruses or fungus. It has been proposed that this high-powered defense-system may often be triggered by stimuli other than parasites and that is the cause of our reacting allergically to normally harmless substances. Like allergies, I think it possible that the shell building mechanism of the abalone is often set in motion other than by trauma or alternatively, by trauma other than that which this system could defend against and that this stimulates the mollusk to produce separate, individual, or even clustered pearls.

5. I have read statements by so-called experts on haliotis pearls, that a pearl is produced by an abalone only once in many thousands of cases. My experience is that this is simply not true. I have found, and presently possess between 30 and 40 abalone pearls and I have gone through less than one thousand shells--quite a few less, to be sure--perhaps as few as a couple of hundred. Every one has been found attached to or even completely embedded in, abalone shells. Usually when I have found them, there have been more than one, often several, usually clustered together in close proximity. This leads me to believe that abalones are much greater producers of pearls than is generally thought.

6. I tend to think that these pearls, which, from their placement, seem to me to come from the mantle, are produced away from the shell surface until a point in time when they are, for unknown reasons, released from the tissues where they are formed. I propose that most likely, most of these pearls simply drop out of the shell and are "lost" on the sea floor. I also propose that the conditions under which the pearls become attached to the inside of the shell require special circumstances. These circumstances would probably be a combination of A. the abalone being at rest; and B. that it be during a period when the abalone is actively producing either conchiolin or nacre, thus creating conditions by which the pearls might be attached firmly to the shell and thus not drop out when the creature is in motion. The abalones then continue to lay down layers of shell on and over these pearls, sometimes embedding them in the shell entirely, until the creature dies.

7. Should my proposal prove true, then most of the pearls produced by the abalones in the wild are never found. It is possible that a wealth of abalone pearls are not being harvested. In a world in which natural pearls are becoming vanishingly scarce, it would seem valuable to me to find some way to recover these pearls before they are lost or destroyed through natural processes on the sea floor.

8. This might depend on the abalone's behavior patterns. I know little of this, but have read that haliotis may stay within a territory or live or at least rest in a specific place for most or much of it's lifetime. If this proves true, then it might be possible to recover the pearls that an abalone produces and subsequently drops by searching, perhaps by sieving or by a vacuuming process, appropriate substrates in it's territory. If true, then an abalone might, possibly, then be of more value alive and living free then dead and harvested. This could be a tremendous boon to threatened abalone populations.

9. Governmental bodies might then develop systems giving rights to the abalone pearls within specific territories or even to specific abalones to individuals or groups who then, to guard their source of pearls, would become protectors of these abalones.

I have thought this over for several years and think that it is a plausible hypothesis and worthy of investigation. Other than biochemical and/or structural analysis, to discern the processes by which they form, I think that the next place to investigate would be commercial abalone farming enterprises such as are found in New Zealand. If a way could be found to retain any of these pearls then that might establish that at least some haliotis species do produce and drop free pearls. It might provide a boon to the growers as well.

My only goal in this is the protection and possible restoration of the remaining abalone populations. I do not and have not harvested live abalone and have no interest or part in any venture to harvest abalone or their pearls. All of the shells I have acquired have, to my knowledge, been long dead and were taken long before it was perceived that there was a crisis in haliotis populations. Most of them were attained from sources a long way from any place where they could have been harvested. In fact, a good many of them come from the mid-western US.
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Let me know what you think.
 
Incidentally--I would like to make contact with some of the abalone culturing/farming operations. If anyone could help put me in touch with these folks I would be eternally grateful!
 
Incidentally--I would like to make contact with some of the abalone culturing/farming operations. If anyone could help put me in touch with these folks I would be eternally grateful!

We just had an abalone commercial grower for abalone meat contact me by PM. He is not a member so I can't answer him. and ask him to join He is interested in perliculture. I include his message becase we do want him to join and don't have a means of contacting him:
My name is Wikus Erasmus and i'm from Namibia on the northern border of South Africa.

My father is at this stage has the only abalone(Haliotis midae) farm in Namibia.A while ago we had an client that wanted abalone meat only so we started with the process of shukking the animals and one of my guys found a piece of shell which was an unusual shape and i could not figure out where to place it, so i started doing some research and i found pearl-guide.

Since then i have been facinated by pearls and now i want to start culturing them, but i've got absolutely no idea where to start.It would be easy for me to get into things as i'm the hatchery manager and we have a couple thousand animals a month that are lower that c grade and is pretty much worthless on the grow-out farm.


Is there a place or someone i could get some information regarding this?Or if you would point me into ANY helpfull direction it would be very much apreciated.I've got some basic info on the subject but i need lots more so any advice/information would be very much welcome.
 
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Interesting thoughts. It seems abalone would be a good model system to study nacre deposition. I have similar thoughts regarding a type of immune system that senses a wound and then responds by inducing nacre deposition. I believe this type of system was only invented once in evolution and therefore the regulatory factors at the top of the cascade would be conserved. I always wondered whether these mechanisms are similar to those that induce bone formation in humans. If this were true, it could have relevance to medical problems. I saw that there are quite a number of studies that investigate the possibility of immunizing abalone against pathogens. Some of the factors induced during the immune response also have a role in the differentiation of dental follicle cells (aka tooth formation).

There are quite a few scientist in Taiwan who study abalone culturing. I think it is a good idea to link the issue of pearl formation to one that has commercial interest. In essence to protect a species, it might be best to make studying them interesting for aquaculture (food) or medical purposes. Immunizing them against pathogens would cover the former, biomineralization the latter. It would be great to also try to bring a high-profile scientist into the field to study the process. I think there is a beautiful story here linking pearls, developmental and medical science. I have a couple of names floating around in my brain and I can pm them if you are interested.
 
This thread unleashes the imagination! I love abalone above all seacritters and pearly shells. They present mysteries as the nautilus does...completely different mysteries.

JMarcus, Smetzler took on the nautilus himself and uncovered a lot of scientists and scholarship. Maybe you can find a partner in research to help you follow these ideas. They are well worth it and you should be part of it.
 
Addendum...

Addendum...

I received some photos and commentary from Ana Vasilu today that may shed just a bit more light on this subject. The pictures were of Pteria Sterna that had many small pearls imbedded in the mantle. Ana mentioned that in the case of Pteria Sterna they very rarely attached to the shell. Another picture that she sent me was of a P. sternia shell that did have a good number of attached pearls. She said that this was a rare anomaly and that this particular shell accommodated an unusually large number of shell borers. It makes me wonder if this doesn't shed some more light on haliotis pearl formation. To my limited knowledge, there are very few mullosks, if any, that suffer the afflictions of shell borers to the extent that abalone do. It would seem possible to me that the number of attached and embedded pearls that I have found in abalone may be the result of their developing such a high-powered shell repair system. A rather sudden outpouring of conchiolin or nacre might be the cause of more of these pearls attaching to the shell. The P. Sterna with the large number of attached pearls, because of unusually heavy attack of shell borers may have stimulated the mullosk to put it's shell-making system into overdrive, thus trapping a large number of these pearls that were in contact with the shell. This would seem to me to give some weight to my idea that it is this supercharged shell repair system that causes the seemingly large number of haliotis examples that I have found with attached or imbedded pearls. Another thought is that perhaps the attachment of pearls to the inside of abalone shells is most commonly associated with abalones that have suffered a large number of shell perforations. It may be that the fact that I mostly acquire such distressed shells is one of the reasons that I have found such a large number of these examples.
 
JMarcus, Smetzler took on the nautilus himself and uncovered a lot of scientists and scholarship. Maybe you can find a partner in research to help you follow these ideas. They are well worth it and you should be part of it.
The ball is definitely rolling, as scientists have realized that understanding the formation of pearls adds so much more to their understanding of the biomineralization process. One of the great pioneers in the field, Koichi Wada, has become a demi-god to nacre researchers, his life's work summarized in his 1999 Science of the Pearl (as yet untranslated to English).

Marthe Rousseau (formerly head of research for Robert Wan, now CNRS Nancy, France) has recently teamed with Checa/Cartwright at U. Granada to explain and prove once and for all the fact and mechanism of pearl rotation in the sac, a subject of perennial assumption and speculation. This involves understanding and controlling the direction of nacre growth fronts on the pearl surface. Paper should be published before the end of the year.

The pearls believed to be Nautilus offer a special problem, ie an aragonite microstructure that has never been observed in the shell of any pearl-producing mollusk. Under what conditions would a mollusk revert to a supposedly pre-nacreous evolutionary state? As nacre represented a structural improvement in the late Cambrian (early Paleozoic) period, such reversion would need to be avoided in the creation of artificial materials or in medical application.

An exciting time, as in so many things, for better or worse.
 
I received some photos and commentary from Ana Vasilu today that may shed just a bit more light on this subject. The pictures were of Pteria Sterna that had many small pearls imbedded in the mantle. Ana mentioned that in the case of Pteria Sterna they very rarely attached to the shell. Another picture that she sent me was of a P. sternia shell that did have a good number of attached pearls. She said that this was a rare anomaly and that this particular shell accommodated an unusually large number of shell borers. It makes me wonder if this doesn't shed some more light on haliotis pearl formation. To my limited knowledge, there are very few mullosks, if any, that suffer the afflictions of shell borers to the extent that abalone do. It would seem possible to me that the number of attached and embedded pearls that I have found in abalone may be the result of their developing such a high-powered shell repair system. A rather sudden outpouring of conchiolin or nacre might be the cause of more of these pearls attaching to the shell. The P. Sterna with the large number of attached pearls, because of unusually heavy attack of shell borers may have stimulated the mullosk to put it's shell-making system into overdrive, thus trapping a large number of these pearls that were in contact with the shell. This would seem to me to give some weight to my idea that it is this supercharged shell repair system that causes the seemingly large number of haliotis examples that I have found with attached or imbedded pearls. Another thought is that perhaps the attachment of pearls to the inside of abalone shells is most commonly associated with abalones that have suffered a large number of shell perforations. It may be that the fact that I mostly acquire such distressed shells is one of the reasons that I have found such a large number of these examples.

These are the photos that our mutual friend Ana Vasilu sent you...I gathered over 100 little pearls from that shell, which had a terrible case of drill-mussel infestation...the same mussels that cause the Abalone such a pain.
Natural Blister Pearls 2011 050 [800x600].jpgNatural Pearls 015 [640x480].jpg
 
Incidentally--I would like to make contact with some of the abalone culturing/farming operations. If anyone could help put me in touch with these folks I would be eternally grateful!

Hi Marcus,
I?m related to an abalone farm, Haliotis rufescens.
 
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I just want to say thanks for the fascinating and insightful responses. I must apologize for not responding to them yet. I have been under a real time crunch because of a combination of work, having to handle some extra business, and my wife and I getting ready to go on the Prairie Home Companion Cruise.:) My work gets very busy in the summer and I am trying to leave things in such condition that all will be manageable while I'm gone. We leave Thurs. morning and I have to work overtime the two days previous... I'm simply not going to be able to respond to the messages until I return. I should be back by July 25.
 
Hi Marcus,
That cruise sounds just wonderful. Maybe there will be new shell discoveries on the Atlantic side. Enjoy!

Marianne
 
I just re-discovered this thread. Am going to have one fabulous read tonight...

To anyone interested in natural abalone pearls, I chanced upon this documented claim of discovering 30 small pearls in a single abalone in Jan/Feb 2006. Think it can be attributed to a certain Jason Hill's dad at abalonepearls@gmail.com (on links hosted via Karipearls and paradise.net).

Pictures available here:
http://www.homepages.paradise.net.nz/ljhill/NaturalAbalonePearls.pdf
http://www.homepages.paradise.net.nz/ljhill/NaturalAbalonePearls2.pdf
 
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Amazing pictures!,
are they from a southafrican abalone?, (can?t remember the name)
 
These would most likely be H. Iris from Chatham Islands.
 
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