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Small Freshwater Clams


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#1 Guest_Madtom_*

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Posted 01 January 2008 - 02:47 AM

Today I was sampling in a creek on some property my neighbor owns and couldn't help but notice dozens of tiny white clams in the leaf litter and floating mats of vegetation. The largest of these tiny shellfish measured about 1 cm maybe 1 1/2 cm in length. The habitat is a shallow creek that drains into a typical Tupelo/Gum swamp. I will try to post some pictures but in the mean time does anyone have any ideas for a possible ID? I'm located in the lower Cape Fear River drainage in North Carolina. Thanks!

#2 Guest_fishlvr_*

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Posted 01 January 2008 - 02:54 AM

Today I was sampling in a creek on some property my neighbor owns and couldn't help but notice dozens of tiny white clams in the leaf litter and floating mats of vegetation. The largest of these tiny shellfish measured about 1 cm maybe 1 1/2 cm in length. The habitat is a shallow creek that drains into a typical Tupelo/Gum swamp. I will try to post some pictures but in the mean time does anyone have any ideas for a possible ID? I'm located in the lower Cape Fear River drainage in North Carolina. Thanks!


Do you mean millimeters? I've caught small white Corbula clams(Asian clams) that were 1-2mm across, but after they pass that size they start to get their color on them. I would guess that they're Asian clams.

#3 Guest_Madtom_*

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Posted 01 January 2008 - 03:10 AM

No...I am pretty sure it was centimeters...however it is late and I am tired so forgive me if I'm way off the mark. I am not good at remembering measurements unless I write them down (a fish that was a couple inches long will be almost a foot by the end of the day! lol) but I am pretty sure I remember them being about a half an inch long. I will try and catch more and this time get some pictures.

#4 Guest_fishlvr_*

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Posted 01 January 2008 - 03:24 AM

No...I am pretty sure it was centimeters...however it is late and I am tired so forgive me if I'm way off the mark. I am not good at remembering measurements unless I write them down (a fish that was a couple inches long will be almost a foot by the end of the day! lol) but I am pretty sure I remember them being about a half an inch long. I will try and catch more and this time get some pictures.


Are you a fisherman? :grin:

All of the Corbula I've seen at that size have started getting their colors. I'll go scoop some up and see if there are any white ones that big. Are you sure they're clams and not mussels?

#5 Guest_Madtom_*

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Posted 01 January 2008 - 03:45 AM

I might be... *looks up at ceiling*

I will be honest with you...I really do not have much experience with shellfish. I assumed that these were clams because from what I have observed (correct me if I'm wrong) mussels are usually oblong in shape where clams are not. However, I am sure this does not apply in all cases.

#6 Guest_fundulus_*

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Posted 01 January 2008 - 11:15 AM

Sight unseen, half an inch long sounds like Corbicula, especially if you found lots of them together.

#7 Guest_ashtonmj_*

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Posted 01 January 2008 - 12:20 PM

Could be sphaerids...

#8 Guest_Madtom_*

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Posted 01 January 2008 - 12:50 PM

OK...here is a picture of one in my tank. Out of water they appeared a pure white but in the tank they are a creamy brown. Hope this helps with an ID.

Attached Files

  • Attached File  clam.JPG   68.79KB   1 downloads


#9 Guest_fishlvr_*

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Posted 01 January 2008 - 01:12 PM

Definitely Corbula. Nice picture, too!

#10 Guest_farmertodd_*

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Posted 01 January 2008 - 01:53 PM

Definitely Corbula. Nice picture, too!


Well, Corbiculacea, but I think this is a Sphaeriid pea clam, not Corbicula fluminea. Even at that size, fluminea would have distinct ridges.

I think some (maybe even most) of what you've been calling "corbicula" Steve, have been pea clams. You'll find them both in the same environs.

Todd

#11 Guest_ashtonmj_*

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Posted 01 January 2008 - 02:04 PM

Definately not a Corbicula. Todd is exactly right. At very tiny sizes C. fluminea and other closely related (hell if I could tell them apart I didn't even know there were so many until a few weeks ago) species have distinct ridges. They are not as compressed as a sphaerid clam either. I find that alot of sphaerids have tiny bumps, small dots, minipustules, whatever you want to call them on their umbos and I can faintly make them out in this picture.

#12 Guest_fishlvr_*

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Posted 01 January 2008 - 04:27 PM

Well, Corbiculacea, but I think this is a Sphaeriid pea clam, not Corbicula fluminea. Even at that size, fluminea would have distinct ridges.

I think some (maybe even most) of what you've been calling "corbicula" Steve, have been pea clams. You'll find them both in the same environs.

Todd


Interesting. I've always thought they were just little Corbicula. I'll have to go scoop some up and look closely at them. How big do they get?

#13 Guest_farmertodd_*

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Posted 01 January 2008 - 04:46 PM

About the size of a pea :)

Todd

#14 Guest_fishlvr_*

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Posted 01 January 2008 - 04:49 PM

About the size of a pea :)

Todd


I guess that makes since. I know, I can be a little slow at times. :roll:

How do you tell the difference when they're 2mm across? Do the corbula have ridges at that size?

#15 Guest_farmertodd_*

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Posted 01 January 2008 - 04:55 PM

How do you tell the difference when they're 2mm across? Do the corbula have ridges at that size?


You can feel the ridges on the corbicula with your thumbnail.

Identification of pea clams is difficult. Many species are indistinguishable until you get them under a microscope.

Todd

#16 Guest_ashtonmj_*

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Posted 01 January 2008 - 04:56 PM

Again, yes even at that size Corbicula have ridges. They are also more inflated and have a different shell texture.

Your answers are too fast if anything...

#17 Guest_mikez_*

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Posted 01 January 2008 - 10:00 PM

That's cool! I have one of those in one of my tanks too. I'm in Massachusetts, would that also be a pea clam?
Mine moves around sometimes and extends a syphon but I don't there's much suspended food for it. Do they usually survive in captivity?
My came in unnoticed in some oak leaves I took from a pond bottom.

#18 Guest_nativeplanter_*

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Posted 02 January 2008 - 12:26 PM

OK, I know mussels are do-not-touch as far as collecting goes, since so many of them are endangered and they are hard to tell apart. What is the general status for clams? How does one tell the difference between a mussel and a clam?

#19 Guest_ashtonmj_*

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Posted 02 January 2008 - 12:59 PM

Corbiculidae and sphaeriidae have lateral teeth on both sides of their cardinal teeth while unionid mussels do not. Externally clams are much smaller and have central umbos as opposed to nearly every unionid mussel which have umbos that are generally posterior to varying degrees. (Note:this has nothing to do with morphology of zebra mussels). For the most part, Corbicula are bilateraly symetrical too.

For identification of sphaerids try Burch, J.B. 1975. Freshwater sphaericaean clams of N.A. Malacological Publications, Hamburg, MI Xi+ 96 pp.




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