Clam Wipeout - Iron Dosing, Disease?

[mwp]

Clam Perkinsus Disease.

 

Perkinsus marinus (or similar protozoa) affect oysters, abalone and clams.

 

High iron levels cause these protozoa to run rampant, thereby destroying the animals.

 

Low iron levels, or nonexistant iron as you had before, cause the metabolism of the protozoa to remain slow thereby keeping the pathogen in a dormant type state = no harm to the clam.

 

Unfortunately there is nothing you can do at this point. I wouldnt add any more tridacna to the system.

 

Sorry to hear about your clams.

 

WOW and WOW and WOW - there's the freakin' answer? I just did a quick google...the SYMPTOMS match up precisely. Can you point me to any references though regarding the relation of the metabolism to Iron levels?

 

MP

[RayWhisperer]

OOPS! I guess you'll never dose Iron again. That sucks you had to lose all those clams. Atleast now you know.

[Nuhtty]

I have studied the effects of heavy metal toxicity in humans and the role that iron chelators play (chemicals that "eat up" iron making it unable to form molecular bonds) so interestingly I was familiar with research that studied iron chelators and protozoal infections. In this case, P. atlanticus which affects the Carpet Shell Clams.

 

Below I linked a study from 2003 that investigates the role of 2 such iron chelators and their effect on the protozoal infections.

 

I dont know your scientific background so forgive me if I am speaking down to you.

 

Here is what the study showed:

- Iron chelators inhibited the growth of P. atlanticus

- No growth of P. atlanticus = no dead clams

- Removal of iron chelators (therefore the ability for iron to be used in the protozoa again) = protozoa grew more rapidly

 

So when you added the iron to your system you allowed the Perkinsus protozoa (difficult to tell which species in this case) to grow and therefore kill your clams.

 

There is no known "treatment" per se, but removal of iron from the system should be all that is needed.

 

I would recommend water changes and removal of all clams, abalone, scallops and other similar animals from your system.

 

Continue water changes until your iron readings are undetectable...then do MORE water changes. I would say a good water change per week for 2 months past the time when there is NO detectable iron would put you in the safe range.

 

From that point on be cautious in the livestock you choose. Try to buy farm raised clams as these specimens are less likely to be infected with the protozoa.

 

Here are 2 links for more reading. Again, I dont know your scientific background so if you need help interpreting any of the data or you want me to help "translate" some of the scientific jargon I would be more than happy to do so.

 

Hope I have been informative.

 

(this is a PDF file so you need Acrobat to read it)

http://www.ualg.pt/fcma/edge/Articles/Elan...20chelator'

 

http://www.pac.dfo-mpo.gc.ca/sci/shelldis/.../perkincc_e.htm

[mwp]

Below I linked a study from 2003 that investigates the role of 2 such iron chelators and their effect on the protozoal infections.

 

Thanks, that's exactly the type of data I was looking for. References never hurt in the scientific community.

 

I dont know your scientific background so forgive me if I am speaking down to you.

 

Here is what the study showed:

- Iron chelators inhibited the growth of P. atlanticus

- No growth of P. atlanticus = no dead clams

- Removal of iron chelators (therefore the ability for iron to be used in the protozoa again) = protozoa grew more rapidly

 

Thanks for the "breakdown"...it doesn't hurt at all with the broad audience a board like this may have. My personal background is limited to briefly studying marine biology at Eckerd College in St. Petersburg FL...long story short, I almost went to Auburn to study aquaculture, but really wanted Mariculture and at the time I couldn't find anyone who offered it. I've settled for an AS in Multimedia Communications instead

 

So when you added the iron to your system you allowed the Perkinsus protozoa (difficult to tell which species in this case) to grow and therefore kill your clams.

 

Makes perfect sense.

 

There is no known "treatment" per se, but removal of iron from the system should be all that is needed.

 

Again, makes perfect sense.

 

I would recommend water changes and removal of all clams, abalone, scallops and other similar animals from your system.

 

Unfortunately that's not possible...simply no other place for them to go other than the "other" tank which has a Coral Beauty who developed a penchant for clam mantels! What about molluscs other than bivalves, or are Perkinsus specifically a pathogen of bivalves?

 

If I follow the basic logic of the quick synopsis above, wouldn't I be "OK" to simply cease dosing iron and let the macro-algaes do their thing? It seems that Iron is simply a limiting factor for Perkinsus growth, as it appeared to be for our Macro Algae growth. It sounds like Perkinsus could remain for a long time despite a lack of iron and hosts, but by the same token it should never become a problem unless Iron becomes more available again. I can already see that water changes with our tap water *could* be a future problem...no doubt we have a some amount of Iron present in our tap. Every time I do a water change I could be briefly elevating the levels of iron, thus giving Perkinsus a stronger foothold....

 

Continue water changes until your iron readings are undetectable...then do MORE water changes. I would say a good water change per week for 2 months past the time when there is NO detectable iron would put you in the safe range.

 

Ah, but here's the only discrepency. We've never HAD "detectable" levels of iron/chelated iron, at least none that could be detected by the Seachem Iron test, both in normal and low range. I definitely was putting Iron in the system though...Kent's "Super Chelated" Iron. As they descibe their product; "Provides bio-available iron...." The "ingredients" include iron EDTA.

 

Despite never being able to reach any detectable levels of Iron, we did notice improved macro-algae growth. I have yet to read the full documentation below, but based on your quick summary, wouldn't the Chelated form of Iron we were dosing not have an affect on the growth rates of Perkinsus sp.? Granted, as I'm not a chemist, perhaps we're talking about different forms of Chelated Iron; the form being dosed is "bio-available", whereas the chelated forms in the studies might have been "unavailable" to all organisms for biochemical utilization.

 

From that point on be cautious in the livestock you choose. Try to buy farm raised clams as these specimens are less likely to be infected with the protozoa.

 

Everything clam in the tank was farm raised except for the Flame Scallop. This individual may likely be the carrier that initially brought it in....it would make sense. The other possible carrier is the Crocea which still remains unaffected, or the two hippopus... We'll never know I guess!

 

Here are 2 links for more reading. Again, I dont know your scientific background so if you need help interpreting any of the data or you want me to help "translate" some of the scientific jargon I would be more than happy to do so.

 

Again, all the info has been GREAT - at least I feel I have a good grasp on what happened, and based on what it appears we now know, there's no way I could have foreseen this calamity unless I had already known about this, and even then I might not have come to the conclusion that all the 'ingredients' would have resulted in a wipeout.

 

I'll have to contemplate our next course of action as a healthy and sizeable clam collection IS one of the ultimate goals for this tank. A UV sterilizer has already been ordered...if Perkinsus spreads freely in the water column, UV no doubt could have helped and could keep the population low in the future, even in the presence of Iron dosing...

 

Thanks again for being the detective that put the puzzle pieces together...phew!

 

Matt P.

[Nuhtty]

What about molluscs other than bivalves, or are Perkinsus specifically a pathogen of bivalves?

 

I am not sure. My research had nothing to do with bivalves but rather the iron itself. I could reference you more iron studies, though!

 

If I follow the basic logic of the quick synopsis above, wouldn't I be "OK" to simply cease dosing iron and let the macro-algaes do their thing? It seems that Iron is simply a limiting factor for Perkinsus growth, as it appeared to be for our Macro Algae growth. It sounds like Perkinsus could remain for a long time despite a lack of iron and hosts, but by the same token it should never become a problem unless Iron becomes more available again.

 

True, I agree.

 

I can already see that water changes with our tap water *could* be a future problem...no doubt we have a some amount of Iron present in our tap. Every time I do a water change I could be briefly elevating the levels of iron, thus giving Perkinsus a stronger foothold....

 

Always good to avoid tapwater.

 

Ah, but here's the only discrepency. We've never HAD "detectable" levels of iron/chelated iron, at least none that could be detected by the Seachem Iron test, both in normal and low range. I definitely was putting Iron in the system though...Kent's "Super Chelated" Iron. As they descibe their product; "Provides bio-available iron...." The "ingredients" include iron EDTA.

 

I have no knowledge of Kent's product, how or what they used to chelate it and the amounts so I cant comment on that.

 

Despite never being able to reach any detectable levels of Iron, we did notice improved macro-algae growth. I have yet to read the full documentation below, but based on your quick summary, wouldn't the Chelated form of Iron we were dosing not have an affect on the growth rates of Perkinsus sp.? Granted, as I'm not a chemist, perhaps we're talking about different forms of Chelated Iron; the form being dosed is "bio-available", whereas the chelated forms in the studies might have been "unavailable" to all organisms for biochemical utilization.

 

Again, no idea what is really in Kent's product.

 

Everything clam in the tank was farm raised except for the Flame Scallop. This individual may likely be the carrier that initially brought it in....it would make sense. The other possible carrier is the Crocea which still remains unaffected, or the two hippopus... We'll never know I guess!

 

It probably doesnt even matter.

 

Again, all the info has been GREAT - at least I feel I have a good grasp on what happened, and based on what it appears we now know, there's no way I could have foreseen this calamity unless I had already known about this, and even then I might not have come to the conclusion that all the 'ingredients' would have resulted in a wipeout.

 

Hopefully this will help someone else avoid the same problem in the future.

 

I'll have to contemplate our next course of action as a healthy and sizeable clam collection IS one of the ultimate goals for this tank. A UV sterilizer has already been ordered...if Perkinsus spreads freely in the water column, UV no doubt could have helped and could keep the population low in the future, even in the presence of Iron dosing...

 

It would probably help to have the UV sterilizer. But I would also use RO/DI water and skip adding additional iron.

 

Thanks again for being the detective that put the puzzle pieces together...phew!

 

Matt P.

 

You're welcome.

[mwp]

Well, it really sucks to report that after going 6 days "incident" free I thought we had cleared the woods. I did a water change on the 3rd.

 

On the 6th our Gold Hippopus went downhill like a rock and died. Today, our last remaining Hippopus also bit it. Perkinsus looks all the more likely; I'm sure the water change introduced "some" Iron (Chicago tap just has to have some...). Our last remaining Crocea seems OK but the coloration has changed...gone is the purple base color, replaced by brown speckles??????

 

Oh well...a UV is on the way and I'll be trying the clams again!

 

MP

[RayWhisperer]

Yeah Chicago tap has ALOT of Iron in it. I don't know if they still make it, but Kent used to make a resin called Toxic Metal Sponge. It was said to remove all heavy meatals from tank water. I used to use it before I got an R.O.D.I. unit. I may still have a can of it around. If you want to give it a try, I'll dig it up. No guarantees as it would be a few years old, but hey, what could it hurt. Post or PM me if you want

 

Found it. Never opened this one, so it's probably still good.

[Nuhtty]

I would suggest switching to RODI before trying more clams.

[mwp]

Ray, thanks for the very generous offer. I may take you up on it down the road!

 

The downside to all this is that this IS a macroalgae/clam tank, so utlimately I'd want to get to a situation where Iron & Clams WOULD be "compatible"...thus I've gone for the UV sterilizer....let's see if that can control the Perkinsus

 

MP

[mwp]

well Hmm. As of last night, we lost the last clam, our last crocea. Guess I can dose all the iron I want now!

 

MP

[Vashner]

No iron.. period..

 

If you change the water our now and again it will have iron in the salt mix. Yes even the basic Instant Ocean is balanced.

 

And do you use Ammo Lock for your water top off's?