Tridacnid Clams

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Charley Waters

Aquarium Advice Newbie
Joined
May 21, 2007
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5
Hello,

I am interested in conducting an experiment using about 30 juvenile tradacnidae clams ~2 cm in length over a three month period. At the end of that time they will be returned to the lagoon.

My question is what size tank should I have to make sure each specimen has sufficient space and access to their share of nutrients, etc. I've spoken with a clam retailer who suggested about 1 gallon per clam, but he may have meant 1 gallon per mature clam, i.e., 15-20 cm in length. Like I said, my specimens will be an order of magnitude smaller.

Do any of the experts out there have an answer to that one. If so, I'd really appreciate hearing your opinion.

Thank you,

Charley Waters
 
Welcome to AquariumAdvice.com!!! :smilecolros: :smilecolros: :smilecolros:
I guess the first question I have is...what do you plan on accompishing with this study? Second, what species of clam are you targeting? This will make a difference in advice given.

First and foremost, providing the proper husbandry for this project will likely be very expensive when you figure in the set up costs and lighting cost. Keep iin mind that clams of this size rely on heavy nutrients in the water (as well as light) for nurishment. This type of feeding can foul water without the proper filtration. Clams do not contribute to the bioload as fish do. However, the biproducts of feeding them may be an issue.

If you can, please discribe the type of tank you are planning...to include lighting and filtering.
 
WELCOME TO AA!!!

I am also curious as to the extent of the experiment.
 
Thanks for writing.

I'm in the process of planning the tank. I've gone over Daniel Knop's book regarding nutrient and environmental requirements and there's no question that extensive time and dollars will be required.

I've done quite a bit of field work on projects designed to restore clam populations on atolls in the South Pacific. Species involved were T. squamosa, T. maxima and T. derasa.

Now I'm working on a Master's thesis in Marine Biology that asks whether elevated levels of atmospheric CO2 suppress the calcification process in certain marine organisms, and valve development of tridacnid clams in particular. The controlled experiment (so far, at least) will involve exposing clams to three levels of atmospheric CO2 and measuring response variables.

I hope to collect data over a 90 day period using 30 specimens in each of the three tanks. My question is, assuming that environmental and nutritional conditions are met per clam, what is an appropriate tank size for 30 clams ~2 cm in size? In my field work, there were thousands in huge raceways so it's difficult to gauge what the ratio might be.

Thanks again for your interest. Any ideas?

Charley
 
assuming that environmental and nutritional conditions are met per clam

The larger the tank the easier that will be to do. The tank will be a very different environmenet from a raceway. Clams that small need suplemental feedings that can quickly foul the water.
 
Not sure if I can help at all, but I'd do the longer, more shallow tanks. Shallow for the lighting needs. Deeper tank will need more costly light. You're most likely gonna have to look at supplementing large amounts of calcium too.

Even if 1g per clam is true (I'm doubting it though), I'd still consider a larger tank since more water volume is more forgiving - especially since you're gonna have feeding issues like Lando mentioned. If they say 1g per, I'd still consider a 125g tank. That's 4g per. Or maybe even a custom (or DYI) acrylic that's even more shallow. Consider this advice just my gut talking here, not anything scientific. On the lighting, you may be talking at least 6-8 watts per gallon. I did do a (single) Deresa in a 72g tank which is deeper than the 125 I believe. Lived for 5 years with 4x65 power compact lighting and virtually no calcium dosing. Grew almost twice as large in that environment.


BTW, you didn't play for the Dallas Cowboys by any chance didja??? Just kidding since I'm a die hard Redskins fan
 
Maybe you should check out www.glasscages.com ... I have seen a tank they built for an individual that just wanted a shallow tank for corals. The tank I saw was 100 gallons, 6 feet long, 2 feet wide, and I believe 12-14 inches tall. Seems like that would be a lot easier to light than even a normal 125. At any rate, they will build a tank to your specifications. 8)
 
Sounds like an interesting experiment. A few things I was thinking of....

First, How do you plan on adding the supplemented CO2? If you add it in a closed in environment I would imagine you'd have issues keeping CO2 levels high enough (as it gets taken into the water and used to control pH). I could be totally wrong, just a guess.

Second, wouldn't you need 3 different tanks to use in order to subject the clams to the varying levels of CO2 constantly? Or were you thinking of doing it in shifts with the same tank? You could get three 33 gallon tanks or 3 45 gallon long tanks, both with the same footprint (4 ft long) except the 45 gallon is 4 inches taller.

Lighting would be very important and shallow tanks are definitley better than deeper tanks.

Best of luck. :)
 
Now I'm working on a Master's thesis in Marine Biology that asks whether elevated levels of atmospheric CO2 suppress the calcification process in certain marine organisms, and valve development of tridacnid clams in particular. The controlled experiment (so far, at least) will involve exposing clams to three levels of atmospheric CO2 and measuring response variables.
Thanks for the info. It sounds like an interesting experiment.

I am not sure the whole "size/gal" rule is appropriate here. In terms of a tank...I agree that shallow and wide will be best. It will give you the most light penetration and better water movement with less equipment. In terms of filtration for the tank...I suggest using a LS substrate with some LR for added biological filtration. The use of refugium would also be very helpful. I am not sure what macroalgae grows in the area you are trying to duplicate but adding some would be very helpful.

A LFS by me has a very nice acrylic frag tank that would be perfect for this. It is 4ftx4ft and only about 8in tall.

Sounds interesting...keep us posted on the process.
 
Hello, and thanks to all of you.

Yes, I will have three separate tanks.

One of you believed 1 gallon per specimen might not be enough. Do I understand that correctly?

Another wrote that 33 or 45 gallon tanks would be sufficient. Do I understand that correctly?

The long, narrow and shallow solution is a great suggestion.

Thanks to you all for your input!

Charley
 
I like 33 and 45 gallon LONG tanks because of the height. They are only around 12-17 inches tall and longer, which would be near perfect for your setup.
 
One of you believed 1 gallon per specimen might not be enough. Do I understand that correctly?

Yes, but based on absolutely no scientific reasons, only that the feeding needs for 30 clams makes me nervous about food waste. I was following up on Lando's mention of similar concern.
Keep iin mind that clams of this size rely on heavy nutrients in the water (as well as light) for nurishment. This type of feeding can foul water without the proper filtration. Clams do not contribute to the bioload as fish do. However, the biproducts of feeding them may be an issue.
That's why I also like his idea of a refugium - I'd guess connected to both or all 3, whichever the case. I'd imagine all clams need to be in the same water for the experiment. I guess I'm thinking to plan for 4 tanks in you go smaller since the refugium will give you more water volume which is easier to maintain and not as subject to drastic swings if something is wrong for a bit.

Also, keep in mind that 3 tanks will require 3 sets of lights. More money of course.
 
Ray's idea leads me another. You might get away with using 3 - 10 gallon tanks with a large sump/fuge. You could use something like a child's backyard pool for the sump. Add a bunch of macro algea and a skimmer for nutrient export.

You could use a single pump spilt off to a 3 way return to the tanks. That would be close to the raceway condition you previously had. Lighting would be easy to maintain on the small tanks too.

The tanks would all have the same water conditions with the only variable being the atmostpheric CO2. I have no idea how you plan to maintain that with the gas exchange going on in each tank, but I assume you already have that figured out.

Hope that helps.
 
cmor1701d said:
The tanks would all have the same water conditions with the only variable being the atmostpheric CO2.
But if only one sump was used for all three, wouldn't that change the variables?
 
Scott --
The thesis project
asks whether elevated levels of atmospheric CO2 suppress the calcification process in certain marine organisms, and valve development of tridacnid clams in particular.

Therefore the only variable should be the level of atmospheric CO2. The water parameters should be the same for all the tanks.
 
Right I got that part, but if you are running all three tanks back to the same sump/fuge, wouldn't that have an effect on all the tanks, unless I am just way off. You with have three tanks with three variables going into one sump/fuge, would that not effect the experiment? Just curious....
 
Just a Noobs suggestion. You mention putting the Clams BACK in the lagoon once your done. Does this mean you have access to this lagoon?

You could just use water straight from this lagoon everyday and that should really help with the issues of high nutrient water that would result from the feeding. Just a suggestion.

Go Redskins ! Yup even in the UK they have skins fans :D
 
It depends on how the CO2 is added to the tanks, and how successful that method is, whether the three tanks can be run off the same sump. Experiment-wise, it would be better for all three tanks to run off the same sump, but I would set up the whole thing and test to make sure the CO2 levels in the tanks are what you want them to be before putting the clams in....if you can maintain the levels you need on one sump, then you're all set. If not, then 3 separate systems, but you're going to have to be really careful to address conditions so that you don't get a confounding variable.

Personally I think 3 -33 gallon long tanks, run to the same sump would be best. If they ahve separate lighting systems you need to check that the amount of light reaching the bottom of each tank is the same (use a PAR meter). if the tanks are close together then it might be necessary to put dividers between them so that the middle tank doesn't end up with more light than the end ones. My lab uses MHs for experiments and we have to shield them because of this.

I am by no means a clam expert but I am a 5th year oceanography PhD student so please ask any and all questions and I will do my best to answer them!
 
Hi,

Thanks for the info. I think I need to use three closed systems because I expect a relationship between elevated levels of CO2 and decreased pH levels for each of the three treatments. It seems that if I use the same sump, elevated acidity would basically contaminate the entire supply.

In any case, the idea of dividers between lights is an extremely helpful suggestion and a great contribution to design integrity. Thank You!

Charley
 
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