Bali Indonesia Pearl Farm

[Cyril Roger Brossard]

Interestingly enough, there are no known diseases in most shellfish. They have parasites, predators and can be contaminated by sewage, pollution or red tides but cases of mass mortality from systemic or metabolic causes are extremely rare.

Ha? I mean and just to name a few: Mikrocytos mackini, Haplosporidium nelson, Bonamia, Ostracoblate implexa, Marteilia, Rickettsia, Chlamydia…

This said I tend to agree that in proportion there are less deadly (for the carrier) diseases in most mollusks as compared as in ichthyology.
I do take it that you never experienced any kind of mass mortality, which is good.

When you say that there is no dirt really I do understand that this is correlated to your production in Canada, but I think that Indonesia might tend to have higher fouling due to the overall higher temperature. And yes the fouling may be mostly bryozoans, hydrozoans, as well as a few competitors and in the end represent an insignificant dent considering the total water mass within a concession.

Thank you very much for this detailed reply, I certainly learned a lot.

 

[Lagoon Island Pearls]

You certainly have a wide knowledge of pathogens. I'm little out of my league on international recurrance, but can speak to local issues. At the risk of derailing this thread with an unrelated topic, I'll be brief as possible.

Mikrocytos mackini was detected once in Lemmens Inlet (less than a mile away from my farm), but it didn't proliferate and has not been detected since. It was suspected to have been transmitted from relayed seed oysters as opposed to a natural outbreak.

Haplosporidium n. orginates in protozoans and is carried by annelids, making it a secondary infection.

Bonamia ostrea was studied intensively in the late 90's by DFO. The two main species of my forte, Mytilus edulis (mussels) Venerupis philippinarum (clams) could not be naturally nor experimentally infected nor did they appear to act as vectors nor intermediate hosts for the parasite (Culloty et al. 1999).

Ostracoblate implexa was once implicated in a mass mortality of razor clams (Siliqua patula) in Washington State some forty years ago, but was deemed an isolated incident.

Marteilia sp. is also a protozoan parasite affecting oysters but no known infections have been recorded in local stocks.

Rickettsia r. aka epidemic typhus or Rocky Mountain Spotted Fever, is not necessarily a disease specific to shellfish although they can carry it. I'm not aware of any mass mortalities as a result of it, but if you have any knowledge of an event, I'd be interested in reading the report.

As an interesting side note, Rickettsia is being tested in controlling the HIV virus in humans.

Chlamydia is a bacteria affecting mammals but carried by birds and shellfish. Again, if you have any knowledge of mass mortality, I'm curious to know.

Most of these apply to oysters only and not necessarily related to pearl farming on the whole. I was being careful to state there are no known diseases in "most" shellfish. Probably better wording would be: no highly pathogenic infectious diseases are known to occur on the west coast of North America.

About thirty years ago, a mass mortality was reported in a single (albeit large) bed of Manila clams (Venerupis philipinarium) in the Strait of Georgia. While Brown Ring Disease is known for mass mortalities in Atlantic Canada, Asia and Europe, studies have shown local clams of the same species to be highly resistant to infection from Vibrio tapetis. Empty shells remaining from the die off showed no evidence of of BRD, which almost always affects the shell lining at the level of the periostracum.

We do get mass mortalities occasionally in the intertidal zone from freezing. In fact, every single exposed natural Mytilus c. at Lagoon Island a few years ago due to extreme cold, but have since recruited themselves. I expect it takes upwards of ten years to return to traditional levels, whereas mass mortality occurs only after many decades and only in the inlets.

On fouling. It's often misunderstood, that growth rates in northern waters are somehow retarded when compared to southern oceans. Of course, the mean annual temperature is lower but the number of food cells/ml is considerably higher. Naturally, in winter, shellfish and other organisms are only able to digest smaller cells, but in summer they become exceedingly voracious. In the temperate zones, the sheer volume of cells uptaken far exceeds the mean average of invertebrates in southern seas. Basically, in winter we don't defoul much at all, but in spring, summer and fall it's an intensive task hauling and air drying suspended inventory. Intertidal inventory, pretty much cleans itself.

 

[Cyril Roger Brossard]

Yes, I do remember the fouling in northern waters and as compared with southern waters we tend to have differences not only in terms of volume but biodiversity and speed of growth.
Funny you mentioned V tapetis, I excluded it from the list, this said I have seen similar infection on Pterioida , although it was not concluded with mass mortality as what I observed in both Ruditapes philippinarum and Ruditapes decussatus some 24 years ago.
No of course, as you mentioned, not all vibrio or pathogens are directly responsible of mortality, however mortality is often induced due to subsequent weakening and indirect lowering of dissolved oxygen due to mass mortality.
Dave (if I may) thank you once again for this interesting sharing, it is noteworthy that the pearl industry seems not** be affected by the problems that concerns some of the edible species, such as what happened in "etang de Thau" in southern France with the quasi eradication of all spat of Crassostrea and this for the past four years (OsHV-1 and V splendidus), or is it because it is not reported? (**)Port Moresby 1970, Burma in 1983, Japan 1996 are some example for which the exact cause seems not have been found (V harveyi found but not on all batches).
Thank you as well for the description of your operation it indeed brought back memories.

Cheers.

 

[Ramona]

Perhaps mass mortality is more a problem of aquaculture and stock selection (did they do that in France?). Since most pearl farms probably use wild or still genetically diverse stock, they may not see this as a problem yet. Having said that I thought Japanese pearl farms have had mass mortality or mass infection problems in the past? Once genetically modified oysters will be used for farming, I would expect problems to increase. Stressors introduced by "global warming" will probably also independently contribute.

 

[Cyril Roger Brossard]

My two cents:

Perhaps mass mortality is more a problem of aquaculture and stock selection (did they do that in France?). Since most pearl farms probably use wild or still genetically diverse stock, they may not see this as a problem yet.

I do not know if France could be used as a good example for aquaculture, pisciculture is bound nationwide to respect stringent water control yet they are victims of the highly charged effluents from overly cultured fields (corn being one of the worst due to the insecticides), as well as nitrate filled water from industrial piggeries. You can see the major blooms during summer where the rivers meet the ocean.
Ostreiculture is closely following this path as being invaded with various problems ranging from anoxic crisis, benthic mortality, contamination with faecal bacteria, plankton death, nitrification…
Again I am no specialist in this field. But feedback from French producers is quite alarming.

I thought Japanese pearl farms have had mass mortality or mass infection problems in the past?

There were several occurrences of mortality reported and studied.
Japan, Ehime prefecture 1994, possible cause, low level of glycogen in diatoms, feeding allowed but growth hampered.
Japan, Ehime prefecture 1996, possible cause infectious disease in the circulatory organs.
Japan, nationwide 1997, 50% of the biomass died, the remaining 50% produced lower quality pearls than previous years. Possible cause glycolysis (akoya-virus).
Japan, Okinawa 2002, possible cause environmental stress on spat stage due to pathogen (not specified).

But also
India, Pambau area, 1978, possible cause anoxic conditions due to bloom of Trichodesmium thiebautii.
India, Tuticorin area1989, possible cause unknown, 80% of the spat died within a month.
Australia, Dampier 1996, possible cause inability to properly feed due to bloom of Trichodesmium erythraeum (dilatation of digestive glands).
Australia, Exmouth gulf 2006, possible cause mantle lysis yet no infectious agent identified.

Pathogens are not always the main cause of mortality, viral infection while being responsible of some wide scale mortality isn’t the only concern to pearl farmer.
This said I do not know if all occurrences are reported to the academic community (for research purpose). There might be other cases that we are not aware of, maybe someone more informed could add information on this.

 

[CortezPearls]

Came late to this thread and I don't see I can contribute much...the detailed exchange between Dave & Cyril has been fascinating and I believe I will have pathogenic nightmares tonight.

One thing I believe is that many times producers like to blame an invisible & unknow (unidentified) pathogen for their massive mortalities, but many a times it is the cause of pollution and environmental degradation (and genetic manipulation too). And if mortalities are due to a disease or outbreak it usually happens when the animals are feeble, stressed or weakened already due to some environmental or handling problem.

Anyway, just wanted to thank Mike & Peter for sharing the photos and the video. Great photos!

 

[Cyril Roger Brossard]

Dave,
Infections by members of the genera Chlamydia and Mycoplasma have been described in a variety of adult bivalve mollusks, such as oyster, scallop, clam, mussel, and cockle, as stated in his post by CortezPearls the mortality here is caused by the subsequent weakening.
Chlamydia tends to alter the host tissues that are crucial for feeding and breathing, leading ipso facto to a physiologic weakening (add to trace back my notes for this one...). Hope this answer your query.

 

[Sutrisno]

Long standing productions of big companies as a sign of environmentally friendly farming is something i never thought about. That is pretty awesome actually. Knowing that many farmlands and aquaculture experience huge problems after/aroud 10 years of production or less while some pearl farms are litterally older than me does put it in perspective for me at least. When the farming method is not sustainable problems will definitely arise.

I can only speak about indonesian farmers and that is also only for a few tht i have spoken to.
Indonesian farmers i spoke to have 1 problem they always rant about, cyanide fishing. Apparently it is the biggest source of fatalities for many farmers.

I don't think this happens anywhere or it might just be farmers blaming others for their poor performance. No formal research has been carried out that i know of.

 

[Cyril Roger Brossard]

Interesting remark on the effect of the cyanide on the pearl farms… Do they have studies on this or is this just an assumption?

Indeed cyanide toxicity inhibits aerobic respiration. Fish are also the most susceptible organisms - sensitive species exhibit chronic and lethal effects at as low as 5 to 7 grams/liter (chronic) and 20 to 76 grams/liter (lethal), respectively (Eisler 1991). Coral species exhibit chronic and lethal effects at as low as 1 gram/liter (chronic) and 10 grams/liter (lethal) (Jones 1997).

Free cyanides readily degrade in the open environment but persist in groundwater. They do not bioaccumulate. (Eisler 1991)
Cyanide affects photosynthesis, causing as well the loss of zooxanthellae from corals (suppression of respiration as explained above AND algal photosynthesis).

Numerous biological and abiotic factors are known to modify the biocidal properties of free cyanide, including water pH, temperature, and oxygen content; life stage, condition, and species assayed; previous exposure to cyanide compounds; presence of other chemicals…

Phytoplankton may be lethally affected by a volume of above 10ppt. This said about 20ppt (Johannes, Riepen 1995) is released per single bottle squirt, enough to kill any fish in direct vicinity but after dissolution the concentration falls to levels measured in ppb.

Given this it is to be noted that coral may require from six months up to one year to recover from a single cyanide exposure.

I failed to prove how cyanide would be detrimental to the oyster except indirectly.
It would be interesting if anyone could provide the LC50 of NaCN for marine mollusks (excluding Tridacna that is).

 

[mmutiara]

i know absolutely nothing on how cyanide affects pearl farming, but i had clients (was a business consultant for marine parks n ngos) who dealt with cyanide probs. interesting you mentioned it takes up to one year for corals to recover. since so many acreage of corals died from cyanide, it mens the cyanide exposure is pretty bad, right?

 

[Sutrisno]

Hi Mr Brossard,

Accounts differ from farmers to farmers, like I mentioned, no formal studies were ever made and it could be just be blaming cyanide for poor farming methods or even natural cycles. Though local 'studies' do point at the correlation in drops of harvest quantities of various things such as sea cucumber and fish amount over a period of time. It is very hard to prove or disprove as there really are no scientific record keeping of water quality, temperature and catch amounts in the 'affected' areas.

Interestingly enough the effect ( if any) of cyanide fishing according to farmers and local fishermen are quite far from the reputed cyanide fishing areas. One reason being it is of course, an illegal form of fishing and as such done quite far from the villages or pearl farmers who believe this practise is destructive. So the cyanide fishing could be done 2 - 4 miles away from farms/harvest grounds and yet farmers/villagers report lower catches and afore mentioned death of oysters. Which is mind boggling, as the cyanide would have been very very dispersed by the time it reaches them ( micro grams per liter?). ( thus my post saying it being not proven)

I am a very big opponent of any form of destructive fishing method and yet even I find mass oyster death due to cyanide fishing feel like mostly blaming others for one's mistakes or even a natural cycle. Though I do ( ahahaha) help flame this unproven view as it does gets more people working in pristine areas aware of such practises and help look after their plot of sea.

 

[Lagoon Island Pearls]

It's food loss both immediately and from loss of recuitment.

Likewise, the bacteria from decaying organisms become suspended eventually, hence some uptake in the residual or replacement fauna. It drifts around. Some places far and a lot.

Around here, local bays and inlets behave differently, but they depend on inter mixing to activate known events. It's after certain tides when plankton blooms and critters spawn at their greatest rates.

If anything, by virtue of their own procreation, pearl farms do well to replace some of the food lost from mass mortality or other environmental stress. (Not to mention filtering)

 

[Cyril Roger Brossard]

it mens the cyanide exposure is pretty bad, right?

Yes it is, the growing restaurant-based demand for live fish in South-East-Asia is a contributor to the destruction of a fragile ecosystem. Mean to say the disruption of a biome as a resultant from the poisoning of an ecosystem..


Now "bleaching" being the most publicized effect by the media; although such is mainly caused by higher than average SST, that is any temperature above 30˚C, the actual destruction of the coral should not be solely attributed to illegal fishing:


Hi Sustrino, I do agree with your post, still it is very difficult to prove or disprove as you do realize that due to (1) dissolution of the NaCN to part per billion, (2) absence of bioaccumulation, (3) destruction of the coral and possible recovery counted in thousand of ˚days (5000 to 10000), it remain difficult to pinpoint with accuracy to it's effect on wide scale area.

This said and as underlined by Dave, plankton depletion and subsequent hypoxia with exposure due to upwelling current is indeed a plausible cause (and verified in Asia) of weakening, exposure to bacteria and eventual death.

 

[Ramona]

There is a new study out in PNAS about corals in the Barrier Reef. The looked at the various influences of coral reef disappearance. Not sure whether that applies to other areas as well.
http://news.mongabay.com/2012/1001-hance-greatbarrierreef-halved.html

 

[Cyril Roger Brossard]

I think that temperature is the most critical problem, higher temperature induces more intense storm (typhoon, cyclone), both resulting in either mortality due to high temperature (30˚C gap) or due to coral destruction (cyclones). This is actually quite fascinating to consider this whole problem as being like a slope, a continuous slope…
Ramona, the link you posted is very interesting.
Crown of Thorn are blooming in South Eat Asia because the natural population of Giant triton a natural predator (Charonia tritonis) is on the decline (well overfished).
(from the web)



The Humphead Maori Wrasse (Cheilinus undulatus), another natural predator of acanthaster, has been as well overfished (declared illegal in Queensland only in 2003…)



And finally larvae are a source of food for many juvenile fishes in the coral reef, remove the fish (cyanide fishing?) and the ecosystem becomes unbalanced.
Deforestation in coastal zone does as well its part, excess of nutrients following floods do a boost to the development of larvae.
This is really a fascinating global problem and in my humble opinion one that is not easily resolved.

PS: look again at post#53, I noticed that the attachment wasn't loaded properly, the pie chart is quite straight forward.

 

[Sutrisno]

How it affects ecosystems and pearl farmers is truly truly a mystery, yet, the local 'studies' does show a correlation as such. Interesting huh? I just try to keep them cyanide fishers as far away as possible from my area, and uhm... DEMONIZE THEM!

One of my pet projects currently is the culture of Cheilinus undulatus. Unfortunately getting the eggs is a bit of a problem right now. They are insanely greedy of crabs.

 

[fxanphuc]

Hi Buddies,

How i can to go go there,
please advise me

Thanks you
FX