Mussel ID please
Posted 11 October 2014 - 10:42 AM
We are east of Atlanta on the Yellow River a trib of the Ocmulgee. Can anyone help me tell the folks here what they saw?
I also have an aquarium set up with fish we caught at this event. But I don't know the mussels. image.jpg 98.19KB 7 downloads
Posted 13 October 2014 - 11:57 AM
Posted 13 October 2014 - 01:07 PM
Posted 13 October 2014 - 01:10 PM
Posted 13 October 2014 - 01:52 PM
Posted 13 October 2014 - 02:12 PM
Posted 13 October 2014 - 03:45 PM
Posted 13 October 2014 - 04:17 PM
Edited by UncleWillie, 13 October 2014 - 04:22 PM.
Posted 13 October 2014 - 04:48 PM
Posted 13 October 2014 - 07:04 PM
Posted 14 October 2014 - 01:19 PM
"Its hard to tell for sure from the photo due to the angle but Elliptio dariensis (Georgia Elephantear) is a possibility. The posterior ridge doesn't look quite sharp enough and the shape from the younger growth rests looks more like Elliptio hopetonensis (Altamaha Slabshell). This would make a bit more sense biologically as well since E. dariensis likely uses American Shad as a host. I have not seen E. dariensis upstream of Juliette Dam on the Ocmulgee and this appears to be the most upstream that American Shad can migrate. Elliptio hopetonensis generally is one of the most abundant mussel species we have upstream of the dams in the Altamaha Basin."
I strongly suspect that the individual in question is the Altamaha Slabshell. In general, the Georgia Elephantear tends to have a very sharp ridge with some small corrugations or crenulations on the slope near the very top. They usually are shorter and more inflated than other species the appear similar. The Altamaha Slabshell on the other hand is generally a compressed shell with a "hatchet head" shape to it. The ridge is low and rounded and in my experience, the periostracum (outer covering of shell) tends to be laid down in shingle like pattern with the lower course under the edge of the next course above it. In general, the Altamaha Slabshell tends to be a bit more longer than high which is usually not the case for the Georgia Elephantear.
I've spent quite a bit of time searching for mussels in the Altamaha River Basin but have only found a few mussel species upstream of any of the dams on the Ocmulgee or Oconee. Elliptio hopetonensis appears to be the most abundant by far. I've found then abundantly in the Oconee in the vicinity of Scull Shoals, infrequently in the Apalachee including live individuals upstream of Apalachee Shoals, and abundantly immediately downstream of Lloyd Shoals Dam on the Ocmulgee. I've collected a few in the Yellow River immediately downstream of Cedar Shoals in Porterdale. The other species I've found are the Altamaha Pocketbook in the Apalachee, and some interns I had found a Altamaha Lance in the Oconee near Scull Shoals a few years back.
As mentioned, the Georgia Elephantear doesn't appear to get upstream of any of the dams. This is similar to what we see in the nearby Flint River where the Elephantear (Elliptio crassidens), which was historically known from the entire Flint River, no longer occurs upstream of Albany. The reported host fish for the Elephantear is the Skipjack Herring although any Alosa would probably serve just as well. I beleive that the likely host for the Georgia Elephantear in the Altamaha Basin is also Alosa. We published a note in TAFS in 2013 about American Shad eggs in several freshwater mussel species in the Altamaha River and one of the species that had eggs in them was the Georgia Elephantear. This was also the only species of mussel brooding at the same time that the shad were running. Right now the relationship between the Shad and the mussels is only coincidental but I think that there might be a bit more to it.
Posted 14 October 2014 - 06:17 PM
Posted 14 October 2014 - 09:06 PM
Posted 29 October 2014 - 04:07 PM
In Athens -- Just upriver of the middle oconee shoals there's a little park on the north side of oconee street. 25-30 years ago I used to find mussel shells pretty thickly (we used them to temper some repro pottery in an anthro class once)
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