Nailing a Snail to Protect Catfish

Reporter: Bob Ellison, USDA

Each winter the American White Pelican returns to the Lower Mississippi River Delta to feed on
fish. The pelican carries a small parasitic plant worm that can kill catfish and hurt the Delta
catfish industry. Scientists at the USDA's Agricultural Research Service in Stuttgart, Arkansas
are studying the problem. 

Andrew Mitchell, USDA Agricultural Research Service

It's mature in the bird, produces eggs, the eggs are shed in the water from the bird, they hatch and
form a little organism that penetrates in the snail, they undergo multiple divisions in the snail and
erupts as up to 100,000 units over a period of several months and penetrate the fish and then they
develop about five months to a semi-mature position in the fish where then the bird eats it and in
a very short period of about 5 days it develops in the gut of the bird to an adult and produces eggs
and transfers on.

Reporter: Bob Ellison, USDA

The scientists have developed a chemical combination of copper sulfate and citric acid to target
the fresh water snail. The treatment has proven very effective at reducing the threat of the
parasite to farm raised catfish.

Andrew Mitchell, USDA Agricultural Research Service

In order to stop this we have no treatment for the actual parasite so we have to eliminate or
restrict one of the hosts. The birds are federally protected and that leaves us the snail, of course
we have to keep the fish cause that's our product. So we are developing methods to kill the snail. 

Reporter: Bob Ellison, USDA

This treatment was approved for use on snails by the Environmental Protection Agency and is
widely used in Arkansas and Mississippi for this purpose. As a result the state of Arkansas has
not had a serious snail infestation since 1999. 

I'm Bob Ellison reporting, for the US Department of Agriculture