Snail and Mussel ID

I recently helped someone tear down a large garden pond in Hinesburg, VT (near Winooski River, Lake Champlain watershed). Pond was approximately 8' x 20' with depth up to 40" or so.

There were a lot of large, healthy looking snails, which I believe to be the same as what I found on mud flats in the Connecticut River (between NH and VT) in 2006. From the number, they were obviously breeding. Some specimens were up to 50% larger than what I have here. The pond owner doesn't know where they originally came from -- it was her mother's pond for several years. There were *tons* of these on the Connecticut river mud flats (if they are the same), which makes me suspect they may be an exotic invasive. They clearly feed by burrowing through soft substrate.

 P5270135.JPG   22.93KB   1 downloads

 P5270136.JPG   23.45KB   2 downloads

She believes the mussels may have originally come from Lake Champlain. They had survived in the pond for at least 2 years. Sorry, no pics of dead/empty shells available.

 P5270137.JPG   25.08KB   1 downloads

Can anyone make an ID on these?

I intend to put these in my own pond, but that won't be dug for at least a month. Suggestions on how to hold them until that point? If they're exotics, I don't want them. I'm right on a very pristeen brook trout stream which feeds the Winooski, so I don't want any risk of introducing something that doesn't belong. (Obviously I'll take a lot of care to reduce the chances of a pond overflow to near zero). How do I euthanize them humanely?

Of course I know not to collect mussels, but these came from a garden pond that was being drained. What's the correct thing to do in that case? Can't release, so... euthanize? Or is it okay to try to keep them?

I should add that the other pond inhabitants were a *lot* of breeding fathead minnows (added from a local stream 2+ years ago), and one large goldfish. The edges of the pond were all built up with slate stacked horizontally, so just about ideal egg-laying conditions for fatheads.

The mussel is Elliptio complanata. Not sure what to tell you about what to do with them. If you can't posses then you can't transplant. They are quite ubiquitos to the Atlantic Coast so I wouldn't really worry about an introduction, though if you're in a high gradient brook trout stream drainage they probably aren't found in that reach. Definatey a question best answered by someone in VT. The mussels would have just as good a shot at long term survivability in a dewatering pond as they would being held for a few months in an inadequate system.

Thanks for the ID, Matt.

The mussels would have just as good a shot at long term survivability in a dewatering pond as they would being held for a few months in an inadequate system.

Given that the pond was drained, the liner removed, and the hole filled with 3' of dirt, I think they'll have a *much* better shot at surviving pretty much anywhere else.

What's the native habitat? Do they want clean water or silty/turbid? Like I said, they clearly survived several years in a garden pond, so I assume they don't need a fast/clean stream.

I'll do some research on what the laws say. VT is very small, so our laws are less developed/specific than many other states. I'm in touch with state biologists, though, so I'm sure I can turn up some answers.

If I need to, how does one go about euthanizing a mussel? Hammer? Freezing?

Edited by jase, 03 June 2008 - 12:11 PM.

No problem. Like I said, they are really widespread mussels. Don't really think of them having a 'preferred' habitat like brook trout. Eastern elliptios can be found across a range of stream orders, discharge, stream width, watershed size, substrates, etc. For example from 117 stratified random sites where eastern elliptio was present in Maryland 75% of these records occured in streams with discharge from 0-15 cfs and about 100 to 35,000 acre catchment basins (watershed size upstream of sample location). That doesn't even take into account habitat of ponds and large rivers where we know they exist. We find them in the sandiest and silty of coastal plain streams well into the gravel/cobble piedmont. There are certainly water quality parameters that are lethal to mussels, low DO, high chems, TSS, etc., but if conditions are that poor fish probably won't live either. An artifical pond like the one you found them in provides ample food (green water) which is why some species often are found in farm/gaden ponds. Not necessarily "clean" water, but adequate/proper water quality and good food quality.

Thanks again, Matt.

Anyone know what the snail is?

Looks like some viviparids I've seen, but I'm not sure. Maybe a Cipangopaludina (Asian mystery snail).

I'm also very interested to see if the snail can be identified. Not far from me in LaDue Reservoir they are everywhere, some as large if not larger than a golf ball. Unfortunately I didn't have a camera but they are if memory serves correct identical to what the OP posted. Next fishing trip there I'll make sure I bring a camera.

They are probably Chinese or Japanese Mystery Snail. There is a difference in shell corrugation I believe, just don't remeber which is which. OLLLLLD post...

It's a chinese trapdoor snail. The chinese ones are black. The Japanese ones are yellow. Be sure to keep them in a bucket of water for a week before adding to your tank. The snails will throw up a lot of sticky soil colored stuff that you do NOT want in your gravel.