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It has been proven in Colorado
and throughout the West that very small snails have
invaded streams and rivers for the second time
around, arousing concerns that the invertebrate,
which is fast-spreading, could oust species which
are native to the area and threaten the health of
the region’s marine ecosystem in the long-run.
Potamopyrgus antipodarum or New Zealand Mud Snails,
which are endemic to the Southern Hemisphere, were
discovered recently in the Elevenmile Canyon of the
South Platte River just below Elevenmile Reservoir
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In the autumn of 2005 they were first found in Boulder
Creek, on the Boulder’s northeast. The find was a bit
unexpected, but not really surprising because the closest
known mud snail population is in northeastern Utah’s Green
River.
Biologists of the U.S. first came upon the snails
approximately 20 years ago in the Snake River of Idaho.
Apart from Colorado, they have disseminated into California,
Montana, Oregon, Arizona, Wyoming, and Utah, even in
Yellowstone National Park.
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The population in Lake Ontario is the only other known one
in the United States within Canada’s southeastern area and
New York.
Biologists in Colorado had centered their attention
in Colorado’s northwest because they were worried
the snails might disseminate from Utah’s downstream.
However, so far, there have been no supported
accounts that the snails have disseminated into
Colorado’s Green River.
Experts believe that the New Zealand mud snails
might have been brought in to North America by ships
of European origin sailing into the Great Lakes. The
snails have infested rivers and streams all over
Europe, and seem to be making their way across North
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Although the mud snails can attach themselves to fowl and
other wildlife, human deeds are some other possible way to
spread these snails. Biologists suggest that these organisms
can hide on boats and other crafts used for water, as well
as on boots, nets, waders, and other fishing equipment.
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New Zealand mud snails are almost impossible to
control once they have encroached upon a marine
ecosystem.
For example they are so tiny (only about
six millimeters in length) that it is impossible to
skim them from waters.
Very tough, the snails can
live for many days out of water and can resist a
wide scope of temperatures.
The miniscule invertebrates can even pass unharmed
through a fish’s digestive tracts. Since they are
self-multiplying and give birth to their progeny
“live”, their off-springs come out as well-developed
clones, and you only need one New Zealand mud snail
to begin a new colony in a river or stream. |
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These nonsexual capabilities of reproduction ensure their
survival in the long-run.
The Wildlife division of Colorado is attempting to limit the
dissemination of the snails to other Colorado streams,
through efforts of outreach and through the guidelines
discussed and planned out in a management plan for the New
Zealand mud snail.
Astonishingly, mud snails that have infested the Western
United States are all females and do not necessitate males
to procreate. Put differently, they are a clonal and
parthenogenic species.
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