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Pea/fingernail clams


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#21 gerald

gerald
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Posted 28 July 2017 - 09:44 AM

Auban wrote:  "The thing I find interesting to think about is that drainage ditches are entirely man made structures. They are providing environments for all kinds of little critters to live in that may otherwise have no other suitable habitat later on down the road."

 

In most cases, a drainage ditch is a man-made replacement for a natural drainageway (stream or wetland).  These sites presumably had all sorts of native critters for millenia before they were converted into ditches.  Relatively few ditches are "entirely man made" (in places that were not waters or wetlands prior to ditching).  This is a hot button in the arguments for and against regulating construction impacts to "ditches" to protect water quality.


Gerald Pottern
-----------------------
Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#22 Auban

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Posted 29 July 2017 - 11:15 PM

I wouldn't argue that the environment was there for these critters before we obliterated them and constrained them to mere roadside ditches. I'm mostly interested in knowing what happens to those tiny communities. I would think that any affects that we can produce on them would be much more immediately visible than affects we have on larger aquatic ecosystems.

To me, they seem like an opportunity to study the effects of farm runoff, pollution, etc. They aren't exactly large... Just a little bit of change would probably be easily and quickly observable.

Anyway, to dispel any doubts that I may have clam shrimp, here is a pic of one of the little clams climbing up the side of its tank: https://vgy.me/r6Csvr.jpg
"The ecologist is continually having to look at the aspects of nature with which he is unfamiliar and perforce must be an amateur for much of his working time.... professionals may carp at omissions, misconstructions, or even downright errors in these pages. perhaps ultimately they may forgive them for the sake of the overall vision that only the amateur, or the ecologist, blithely sets out to experience."G. Evelyn Hutchinson

#23 gerald

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  • Wake Forest, North Carolina

Posted 30 July 2017 - 08:14 AM

Looks just like a booger that my kid flicked on a tank once.  Re ditches, yup, just one uncaptured oil change, radiator hose failure, or car wreck could pretty much render a ditch uninhabitable for gill-breathing critters for a year or more.  And in places with public water systems, hydrant flushing poisons them with chlorine a couple times a year (and the headwater creeks they flow into).  Chlorine is gone much quicker than motor oil or antifreeze, but the frequency of  impacts doesn't allow much chance for recolonization.


Gerald Pottern
-----------------------
Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#24 mattknepley

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  • Smack-dab between the Savannah and the Saluda.

Posted 30 July 2017 - 01:37 PM

Booger Clam does seem to be an accurate moniker!
Matt Knepley
"No thanks, a third of a gopher would merely arouse my appetite..."

#25 Auban

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Posted 27 August 2017 - 05:14 PM

So, after observing these guys for a while, I have found something interesting...

They have a tendency to hang out in floating clumps of algae. I am not sure if they were already in the algae and the oxygen bubbles caused the algae mat to lift them to the surface or if they crawled their way up the sides of the tank. But given that I found 23 of the little clams in a single clump of floating algae, I suspect that they seek the floating clumps out.


Someone with more knowledge than I about these things(ahem... Gerald) told me that they do not persist long in the presence of mosquito fish. If they seek the highest level of their environment, this may help explain why. Surface feeders would obviously have more impact on them if they are spending their time near the surface of the water. While they cannot eat the adult clams, they may be able to eat the babies.

I need to get some mosquito fish and test this idea...
"The ecologist is continually having to look at the aspects of nature with which he is unfamiliar and perforce must be an amateur for much of his working time.... professionals may carp at omissions, misconstructions, or even downright errors in these pages. perhaps ultimately they may forgive them for the sake of the overall vision that only the amateur, or the ecologist, blithely sets out to experience."G. Evelyn Hutchinson

#26 mattknepley

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Posted 27 August 2017 - 07:00 PM

Knowing the enthusiasm many fishes have for baby snails, I have no doubt surface feeders could find those clams palatable. I don't doubt they (those clams) may look for/ prefer floating algae for a home. Lots of sea critters like to live in the floating forest of the Saragasso Sea, why couldn't freshies find a reason for that type of lifestyle to work for them?
Matt Knepley
"No thanks, a third of a gopher would merely arouse my appetite..."

#27 gerald

gerald
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  • Wake Forest, North Carolina

Posted 28 August 2017 - 07:23 AM

The fingernail clams in my tubs outside (without fish) seem to stay on the bottom in the sediment.  I've never noticed them climbing sides or in floating algae or plants.  I guess different kinds have different behaviors.  I do find some in flowing streams (often in moss mats or leaf litter) and floodplain pools with Gambusia, but they're typically more abundant in fish-free pools with amphibians.


Gerald Pottern
-----------------------
Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel





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