Basic Questions

[NaH2O]

I think this may be a pretty basic question. Maybe not though, I've found that many things in this hobby seem basic, but are not. Here it goes.... If clams are filter feeders, then they wouldn't do well in a "clean" tank, right? So, if you had a monster skimmer, low bioload, and tried to keep your "undesirable" parameters (such as phosphates, nitrates, etc.) low, then they wouldn't do well? I have an idea that they receive some ,if not a lot, of energy from the symbiotic zooxanthellae. Which method of gathering energy supersedes the other - filter feeding or zooxanthellae? Do they rely on zooxanthellae when there isn't enough food to be consumed and vice versa? Could be I'm turning a simple process into a complex one, or it is in fact more complex than I thought......

EDIT: OK, I guess I should have titled this thread Basic Yet Complex QuestionS

EDIT II: Thank you moderator for changing Basic Question to Basic Questions...LOL

 

[Maxx]

Nikki,
Clams are actually nitrate users....they utilize it to survive....so they will aid in nitrate reduction. Yes a sterile tank will cause you to have to feed the clam, but DT's is a great source of Phyto, as is Kents Phyto-plex. As they get older/larger, (about 2-3 inches) they rely on photosynthesis more than food. I just recieved my copy of Daniel Knops book on Clams, so you'll have to wait on a more detailed explanation.
Nick

 

[Barry N.]

A great question

clean" tank

When I think of a clean tank in relationship to keeping clams, no or very little sand floating in the water as well as slime generated by corals that could clog the gills of the clam.

Far as feeding or not feeding, there still is a lot of controversy in the reef community regarding such.

Dating back to 1936, Sir Maurice Yonge believed that zooxanthellae reproduced and grew in the mantles until needed then transported to the stomach for digestion. Then came a person name Youge 1936 and too many more to mention after that.

A study conducted by Klumpp (1992) that filter feeding was indeed significant to the growth of the clam. His study found that small clams do receive as much as 65% of their carbon requirements from filter feeding. The juveniles having a small mantle surface can not obtain as much symbiotic algae through their mantles so they are more dependent on filter feeding where as the larger clam can obtain more algae with their larger mantle surface. A good rule of thumb, most think that a clam with a least 3" will have enough mantle surface so that they can depend more on zooxanthellae rather than filter feeding.

One thing to take into consideration regarding this on going debate is that clams do have a digestive system.

There is so much more research that has been done in past years, too much to post in one thread.

If you like, I would be more than happy to discuss this more in detail on the phone.

 

[NaH2O]

Thanks for the responses! Barry, that makes sense to me - about the juveniles needing to depend on filter feeding more than larger/older clams. Also, you can't argue the fact that clams do have a digestive system. Very interesting! Karma to you both!

 

[birdman204]

A few interesting things I have read......
Juvenile clams are born without symbiotic algae in their cells. They must initially capture it from the environment through filter feeding. Also, as clams increase in age, their digestive systems decrease in size, and some very large clams have been found where their digestive organs "seem" useless. When they get large, 3 " and up , much of their nutrient uptake can be met thru the zooanthelle in therir mantle. they create carbohydrate energy for the clam to use. Clams can be found in near pristine waters. remember our nitrate test kits are only detectable to a certain extent. according to Knopp, giant clams DO NOT need nitrates to survive, it is however something that they will filter out of the water for consumption. HTH.

 

[Barry N.]

They must initially capture it from the environment through filter feeding.

From past studies that has been the thinking.

Also, as clams increase in age, their digestive systems decrease in size, and some very large clams have been found where their digestive organs "seem" useless.

Not sure I would agree with that but also depends on the spiecies. Example, some species are found in deeper waters such as the T. gigas where they depend on filter feeding more so than the T. Maxima or T. Crocea due to the decrease in lighting.

Over the past 70 years this subject has been an on going debate.

Great subject though.

 

[birdman204]

good point Barry. I was trying to show that it isn't always one thing or the other. I guess I should have worded it a little differently. Good point about depth of environment.
I love the great clam debate.

 

[Barry N.]

If we could only ask the clam Last year we did some research with feeding and non-feeding clams, both positive and negitive test.

Yes, the debate goes on. !