NZ Mudsnails

[GutshotApe]

Anybody else see the article in today's Oregonian about the latest infestation of New Zealand mudsnails? They are now in Garrison Lake in Curry County at Port Orford.

Six months ago there was a report of them being in the upper Snake River and in the lower Columbia near Astoria. How they got 300 miles south to Port Orford so fast is a mystery...an adult or egg could have hitched a ride on a boat or boat trailer from an infected area....could have hitched a ride on a reeled up but still damp fly line....could have hitched a ride on a duck's feathers.

These snails are parthenogenic, or asexual....it only takes one to tango.....they are all exact genetic duplicates. The Garrison Lake snails are identical to the ones in Montana. In New Zealand, they are not a problem and are kept in check by several species of nematode worms....but here, there are no natural controls. In the Yellowstone area they completely take over the aquatic habitat :shocked: and form dense mats of solid snails displacing most other life forms. Fish starve - there are no insects and the snails go thru a fish's gut and come out undigested and alive.

This is not good news, folks. :depressed:

[Fast Water]

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Here is a good page on aquatic hitchhikers:

Protect Your Waters (http://www.protectyourwaters.net/)

From September 10, 2000: (Montana)

INVASIVE SNAILS FROM DOWN UNDER FOUND IN DITCH NEAR MADISON RIVER

On 7/14, AP reports that New Zealand mud snails have invaded an irrigation ditch that runs from the Madison to the Gallatin rivers, raising questions about the impact on trout. One-third the size of buckshot, the mollusks could be the leafy spurge of the Madison River, choking out the caddis, salmon and Mayflies that blue ribbon trout love to nibble. They already have resulted in the closing of the Cobblestone fishing access on the Madison, where they were found in Darlington Ditch, which flows from the Madison.

Biologists are worried the ditch could infect not only the Madison, but also the Gallatin River near Three Forks, where the ditch drains back into the river after irrigating several farms.

Pat Byorth of the Montana Department of Fish, Wildlife and Parks said the state may attempt to kill the snails this fall by draining the ditch and letting the snails dry in the sun. They will have to wait until irrigation season is over. Poison engineered specifically to kill mollusks like mud snails is another possible remedy.

Darlington Ditch could be the first place in North America where biologists were actually able to kill the prolific snails.

A doctoral student at Montana State University, David Richards discovered the snails accidentally while collecting river plants for research May 17. At first glance, mud snails look like coarse black grains of sand. In eddy pools and grassy streams, where they can number a half million or more per square meter, the snails resemble sand bars of black pumice. Their appearance makes mud snails difficult to recognize in the Firehole and Gardner rivers of Yellowstone National Park, where mud snails are prevalent, Richards said.

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Click here for an identification guide. (http://www.esg.montana.edu/dlg/aim/mollusca/nzms/id.html)

[ 03-09-2003, 10:09 PM: Message edited by: Fast Water ]

[Re:Play]

GSA--pretty amazing spread of the critters! :cheers: Probably need a committee to study them.