Researchers Win Tech Transfer Award From
ARS By Jim
February 12, 2003
BELTSVILLE, Md., Feb. 12Developing a pond shoreline
treatment to control aquatic snails that spread disease to farm-raised catfish
has won researchers Andrew J. Mitchell and Billy R. Griffin an award for
technology transfer from the Agricultural
ARS, the U.S. Department of Agriculture's s chief scientific
research agency, will honor Mitchell, Griffin and other scientists today at a 1
p.m. ceremony at the agency's Henry A.
Wallace Beltsville Agricultural Research Center.
Mitchell and Griffin developed their shoreline treatment at the
ARS Harry K. Dupree Stuttgart National
Aquaculture Research Center in Stuttgart, Ark. Griffin recently retired
from the center.
The researchers developed a method to stop a flatworm, known
as Bolbophorus confusus, that can lead to serious economic losses for
catfish producers. Eggs from the flatworm are shed from the American white
pelican's intestinal tract into channel catfish ponds, where they hatch and
form larvae that infect an intermediate host, the ram's-horn snail, or
Planorbella trivolvis. Once the larvae multiply and mature inside the
snail, they exit and find fish to infect. The cycle begins again when a pelican
eats an infected fish and the flatworm reaches maturity inside the bird.
Cases of the disease were first seen in the Mississippi Delta in
1999. Fish infected with B. confusus develop small cysts in their flesh,
often seen as bumps just below the skin. The disease can kill smaller fish, and
it lessens the appetites of larger fish that survive. This retards the growth
of the fish, making them unsuitable for market and susceptible to other
diseases. Currently, there is no cure for infected fish.
Mitchell and Griffin developed technology targeting the
ram's-horn snail. They produced a solution of copper sulfate and citric acid to
apply to the shoreline of fish ponds using a specially designed nozzle. The
snails are killed, but fish are repelled by the treatment and avoid the
shoreline. The treatment disperses throughout the untreated pond water and
becomes diluted to concentrations that are not toxic to fish.
The treatment has proven very effective at reducing the threat
of the parasite to farm-raised channel catfish. The parasite has been found in
catfish in Mississippi, Louisiana, Arkansas, and most recently California. The
treatment is currently being used in Mississippi and Arkansas.
"The researchers have worked tirelessly to present their
findings at several workshops and annual meetings to get the word out and into
the hands of producers and suppliers," said Edward B. Knipling, acting
administrator for ARS.
The researchers began work on the project in 1999, and the
treatment was adopted by the fish industry in 2000 after approval by the U.S.
Environmental Protection Agency. As a result, Arkansas has not had a serious
snail infestation since the state began widely using it.
The scientists teamed up with private industry to develop data
to support the EPA application for registration. They are working with Phelps
Dodge Refining, Inc., of El Paso, Texas, to transfer the technology to new
areas, including control of a serious protozoan parasite of fish. They also
wrote articles for publication in newspapers, extension publications, trade
journals and scientific journals, including the North American Journal of
Mitchell has a B.S. in biology from Glassboro (N.J.) State
College and an M.S. in fisheries from Auburn University. He lives in North
Little Rock, Ark., with his wife, Sandy. They have three children and two
Griffin is a native of Prescott, Ark., where he resides with his
wife, Marsha. They have four children and seven grandchildren. Griffin received
a B.S. in biology from Arkansas Polytechnic College and an M.S. and a Ph.D. in
microbiology from the University of Arkansas.