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GROWING A BETTER CATFISH
AUBURN–If you purchase catfish at your local grocery or restaurant,
chances are you're buying farm-raised catfish. And the chances are good
that your meal was raised in Alabama and that Auburn University had
a hand in its growth.
Alabama is one of the top four catfish-producing states, which together
accounted for 95 percent of the United States' total sales in 2001.
The catfish industry includes both large and small family farms and
is critical for the economic viability of many communities in Alabama
and the South.
To keep this industry growing, Auburn University scientists in the Department
of Fisheries and Allied Aquacultures are developing a hybrid catfish
that could increase farm profitability by decreasing production costs
and improving efficiency.
The mating or crossing of two different species is a process called
hybridization, with the offspring known as hybrids. Hybrids between
different species of North American catfish have been researched for
more than 30 years. Of all these interspecific catfish hybrids (crosses
between two distinct species) only one hybrid has characteristics that
favor commercial application. That hybrid is a cross between female
channel catfish and male blue catfish.
Traits that influence profitability of a commercial catfish farm include
growth rate, overall survival, meat yield, disease resistance and harvestability.
Research trials demonstrated that blue/channel catfish hybrids exhibit
good performance for these traits, which has spawned interest in commercial
culture of hybrid catfish.
"The more traits that we examine, the more we learn that this catfish
hybrid is an especially valuable fish because with one simple breeding
technique, we improve about eight different traits," said Rex Dunham,
fisheries professor and head of the AU Peaks of Excellence hybrid catfish
initiative program in Alabama.
However, there are problems with the production of hybrid embryos. One
is that the two parent species will not readily spawn in ponds. Another
is the current lack of blue catfish brood stock, since virtually all
of the catfish industry is based on channel catfish.
AU researchers are working on problems in artificial spawning and fertilization
techniques that are hampering the mass production of these hybrids.
Scientists are evaluating hormone treatments that induce females to
release eggs to maximize production of hybrid eggs and the hatching
rate of fertilized eggs. And they are developing technology to more
efficiently utilize the sperm from donor males to fertilize the eggs.
"Once we have some of these reproductive problems ironed out a
little bit better and farmers adopt the new spawning strategies, it's
going to be a major advancement in the catfish industry," said
Dunham. "The impact of this fish will be tremendous. Limited field
studies showed that this hybrid, even with the increased hatchery costs,
could increase farm profitability from 20 to 100 percent."
Fisheries and Aquaculture is one of seven multi-disciplinary research
initiatives at Auburn designated as Peaks of Excellence. Research from
the hybrid catfish initiative exemplifies the Peaks programs at work
improving life for Alabama citizens.
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By
Leigh Ann Stribling
May 2002
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