[Zeide Erskine]

I noticed that many forum members are interested in the minute details of perliculture. To satisfy even the greatest appetite for details on the subject click here:

http://www.fao.org/docrep/field/003/AB726E/AB726E00.htm

Of course this exegesis is limited to the mere culturing, it does not go into detail on processing and designs.

And to round it out, here are some freshwater molluscs to culture with, in case you want something other than the same old, same old..

http://members.aol.com/mkohl1/FWshells.html

Zeide G. Erskine

[jshepherd]

Very interesting! What I have found interesting about the culturing in India is the speed of the layering on the pearls. I have corresponded a bit with Dr. K. Sunil Mohamed, Head, Molluscan Fisheries Division, Central Marine Fisheries Research Institute (CMFRI). He sent me a report detailing some of the studies. They are getting an average coating of .004 per day. I know it refers to an old Japanese study of .0004 per day, but even present techniques do not come close.

Study
Nucleus diameter (mm)
Average thickness of nacre (mm)
Duration in years
Coating per day (mm)
Number of times the nacre coating rate is less than present study (6 mm)

Japan

Cahn (1947)
3.05
0.32
2.0
0.0004
8.8

4.10
0.38
2.5
0.0004
9.1

6.10
0.44
3.0
0.0004
9.6

7.90
0.50
3.5
0.0004
9.8

India E coast

Alagaraswami (1974)
3.00
0.32
0.5
0.002
2.3

4.00
0.31
0.4
0.002
2.1

5.81
0.26
0.4
0.002
2.4

India E coast

Dharmaraj and Sukumaran (2003)
3.02
0.85
1.0
0.002
1.6

4.24
0.96
1.0
0.003
1.4

5.14
0.62
1.0
0.002
2.2

Present study

India W coast
5.48
0.87
0.8
0.003
1.4

6.04
1.23
0.8
0.004
-

[Zeide Erskine]

Hi Jeremy,

The Japanese farms are much farther north, they use the smaller pinctada martensii, and they are typically in more saline bays owing to freshwater being used for human infrastructure, all of which cuts down on nacre deposition. The Indian farms should be closer to South Sea figures and are. I also would not put a little growth hormon implant past them but the Japanese pioneered that and the MGH implant strips are now commonplace in the industry. I also would not put a little number fudging behind the Japanese. Their daily growth rates are too consistent for scientific comfort especially considering that the other parameters vary in a statistically significant way.

Zeide

[jshepherd]

It is true, they are definitely farther south, but not much further than Chinese pearling areas like Behai. They are still much, much quicker. Would the martensii difference be that substantial?
The Indian operations are still marginally successful. They have had a keen interest in the success of the Chinese and a lot of questions about their operation.

[CortezPearls]

Thank's for the link! Great addition to the forum!

We've compiled dozens of articles by Indian authors Rao and Alagarswami (and others) but it is always good to have a good review of all their finds.

I do agree with Zeide: the Indians (Hindii) are still more research oriented and their results cannot be compared to a true commercial venture. Still, their efforts and work are appreciated. Knowledge is a True Gift.

It might be good to add that we should always refer to the Akoya Pearl Oyster as Pinctada imbricata...all the previous or former names (all beginning with a Pinctada): fucata, fucata martensii, martensii, etc. have been absorbed into the first description of the species: Pinctada imbricata.

This will be helpful for all newbies...we don't want them to become confused.

[Zeide Erskine]

Hi,

Well, actually, imbricata is the exotic designation. They typical ones are radiata or vulgaris. Pinctada imbricata is specifically used for scientific purposes to refer to the Atlantic variety of pinctada vulgaris/radiata or the Indian Ocean variety of pinctada radiata that produces mostly pink pearls. Pinctada fucata is the least scientific designation for the Japanese akoya with the most specific term being pinctada martensii (fucata). The Japanese akoya is definitely nowhere close to the pinctada imbricata in the narrower sense, i.e. the Atlantic pinctada with which it cannot interbreed. The two are about as close as humans and chimpanzees. Pinctada martensii (fucata) does, however, interbreed with pinctada maculata while interbreeding with pinctada radiata is far rarer and the offspring is infertile which indicates genetic drift but not as great as the drift between the Atlantic pinctada imbricata and the Pacific pinctada martensii (fucata).

Zeide

[CortezPearls]

Someone SHOULD standarize these facts to lessen confussion. I basically agree with Sohei Shirai's Book "Pearls & Pearl Oysters of the World", where many pearl oyster species were "absorbed" into Pinctada imbricata.

Also, an interesting genetic study by Ilyia Temkin (Museum of Natural History, NY) may help further...already read some advances, but I hope he finishes soon!

So...anyone interested on this subject? should we continue using the old syntax or the new one (Shirai's)? Both?