Radix auricularia in the Carp River
Frederick W Schueler
It's hard to get any information on where the European Ear Snail, Radix
auricularia, has been found in Ontario. Clarke (1981) doesn't give any
Ontario records in 'Freshwater Molluscs of Canada,' and when we found
them along the Lake Ontario waterfront in 1994, we fancied that our
publication of this - in http://pinicola.ca/books.htm#APTW - was the
first record for Ontario.
But when I asked around after finding shells in Wiarton in 2006, I was
told that they were "all around the Great Lakes Basin," though nobody
could point me to a publication that documented this (though I see that
the Wikipedia article on the species has some leads)...
In any event, Adam Zieleman and I were out today, trying to find some
Orconectes immunis Crayfish, in streams that were unseasonably full of
water (making the Crayfish inaccessible), and Radix is what we found.
Our first station was...
FWS 2009/273/h Jock River just below Eagleson Rd, Richmond, Ontario,
where the water level was up above the paths previous visitors had worn
in the banks, and were we were basically dipnetting through terrestrial
vegetation much of the time. We both found lots of Green Frog tadpoles,
Adam found one juvenile Crayfish (probably Orconecetes rusticus x
propinquuus), and I got a smattering of snails: Viviparus georgianus,
Helisoma trivolvus, Physa, and Pseudosuccinea ...
Then we went to...
FWS 2009/274/a Eagleson Rd/Richmond Sewage Lagoons outlet, Richmond,
where we sloshed about in a mixture of coarse filamentous algae,
Elodea, Frogbit, and Waterlilies, finding a number of Mudminnows, and a
snail fauna of Helisoma trivolvus and H. campanulatum (mostly) with a
single Lymnaea stagnalis shell (and 2 juvenile Painted Turtles dead on
the road).
Then we went into...
FWS 2009/274/b Richmond Sewage Lagoons, and dipnetted the surface of the
windward corner of one of the lagoons. This was covered with a sheet of
bright green Lemna minor Duckweed which was banded by lines of
grey-brown waterfowl feathers, and dotted by dark dead Scripus
rootstocks. Right underneath the surface was a material with the colour
and texture of the precursor of sewage, which I take to have been
decomposed Cattail leaves, but it was free of snails, Crayfish, and
fish.
We decided to jump to the next drainage basin, and so proceeded to...
FWS 2009/274/c CarpRiver/HazeldeanRd, Kanata, which was a bare-mud
bottomed channelized stream through Cattailly banks in a weedy field,
which I had some trouble convincing Adam was a "river."
Dipnetting here, in stacked Cattail leaves in eddies, and
through patches of Elodea, turned up no Crayfish, lots of Culaea
Sticklebacks & Green Frog tadpoles, some Helisoma trivolvus, a few
Physa, and one snail shell with the flared aperture of Radix.
And so we proceeded to our final station...
FWS 2009/274/d CarpRiver/CarpRd, just S of Carp, where the stream was so
high that Lemna minor Duckweed was being washed down the main channel,
and we continued not to find Crayfish.
Both of us went over our boots into hidden holes. But there were lots of
Radix auricularia, and also shells of very large Viviparus georgianus
among the shells we netted up.
I haven't washed out this sample to see in detail what it contains, but
from here, it looks like the Radix will be new to the known fauna of
Eastern Ontario.
fred.
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Bishops Mills Natural History Centre
Frederick W. Schueler & Aleta Karstad
RR#2 Bishops Mills, Ontario, Canada K0G 1T0
on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
(613)258-3107 <bckcdb at istar.ca> http://pinicola.ca
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