Pearl Harvesting

[jerin]

Do the mussels/mollusks survive the harvesting or not?

Something I have wondered for a long time is whether the mussels survive the harvesting or not.

I know that Akoyas do not survive the harvest but South Sea oysters and freshwater mussels are seeded more than one time and having perhaps 16 nuclei on both sides (the freshwater mussels) I can´t see how they possibly can survive when there are so many pearls to be harvested as the shell has to be opened rather wide? This stress alone should be quite deadly for the poor animal.

I saw a Paspaley video about harvesting of a South Sea pearl and the oyster was totally opened, so the poor animal must have died. Can Jeremy, Kevin or Amanda tell us more about this, thanks.

[jshepherd]

Some do survive and some don't. The majority of shells do not survive.

In Australia we watched a harvest and the re-seeding ratio was probably 10 percent. It was not because the oysters died when the shell was opened, it was primarily due to the quality of the pearl. If the first pearl was not a good quality one, the shell was not re-seeded.

[effisk]

It all depends on whether the farmer intends to re-nucleate the mollusc or not. If he does, then the harvest is done the same way as the nucleation process (slightly pryed open). If not, then the mollusc is just cut wide open and the pearl(s) retrieved... and the mollusc dies in the process.

Re-nucleation is however only done (on a commercial scale) with P. margaritifera and P.maxima.

there's more info here.

[jerin]

Thanks Jeremy and effisk, still these second geration petal pearls for example are tissue nucleated only so in order for a mussel coming that far, you couldn´t seed it the first time with as many as 30 pearls, because then I don´t think it is enough to pry it open only slightly and in order to get them out, you must be careful so the question is: are they seeded the first time with only very few bits of tissue? 10% is not a large numer considering how many pearls are harvested each year in China.

[effisk]

"second generation pearls"? I don't think that would happen in freshwater mussels as these are virtually never regrafted to my knowledge. Freshwater petal pearls are first generation pearls as any other freshwater pearls. I'm not sure they qualify as keshi pearls as they're not by-products of the grafting process, but i'm no expert.

[effisk]

Here's another thread on this topic:
http://www.pearl-guide.com/forum/nat...ter-keshi.html

(and don't pay too much attention to Zeide Erskine's theories... )

[Raisondetre]

I thought the pearl sac remained in the freshwaters, so there is no need for regrafting of any epithelial tissue - it's already there. It's amazing they even survive though.

[jshepherd]

Yes. There are second and third-generation freshwaters. Petal pearls are always second-generation (created by remaining pearl sac), and beaded (CBSB) are second or third generation.

[Pearl Dreams]

So-- what about keshi pearls such as the ones in this post? (the silvery ones to the right) :

http://www.pearl-guide.com/forum/sho...html#post43560

Are these second- (or third-) harvest pearls, formed from an existing pearl-sac? And if so, are they tissue nucleated or do they form spontaneously?

[effisk]

Are these second- (or third-) harvest pearls, formed from an existing pearl-sac? And if so, are they tissue nucleated or do they form spontaneously?

According to what Jeremy says, they would be second or third harvest formed from an existing pearl sac. They're not tissue nucleated as the pearl sac is already formed.

[jerin]

Hi all,

sure I had forgotten about need of tissue only for forming the pearl sac. Everything else that comes later formes without the tissue or is nucleated to give the form (coin pearls) for example, if I remember rightly.

[effisk]

CORRRECT

[GemGeek]

You crack me up, Effisk!

[Nerida]

Me too - thanks for the laugh, effisk!

[pearlescence]

Is that Anne Robinson? She has had so much surgery it is hard to recognise her these days....