Engineered Catfish Could Be Bigger, Healthier

A U B U R N, Ala., Jan. 3, 2001 -- Call them Super Catfish.

A research team at Auburn University is busy mapping DNA, hopingto give Alabama fish farmers an economic boost by showing the wayto produce catfish that are bigger, healthier and easier to catch.

At a secluded compound near the Auburn campus, the catfishgenome lab sits beside a field of 28 small ponds stocked withcrossbred and genetically altered fish. The ponds are covered withnetting and surrounded by high fences topped with barbed wire toprevent the inadvertent release of a genetically altered catfishinto the environment.

Researchers Want Dumb Fish

Nationally, Alabama trails only Mississippi in the production offish. In Alabama, catfish mean $100 million a year to farmers and$125 million to processors.

With cultivation and processing operations both concentrated inthe Black Belt, catfish gives a big economic boost to Alabama’spoorest counties.

Zhanjiang Liu, who heads Auburn’s catfish genome project, isdescribed by fisheries department head John Jensen as “one of ourbest scientists.”

“He has put us in a leadership position as far as genomics,”Jensen said.

Liu grew up on a farm in central China. He attended a Chineseuniversity, then came to the United States for graduate school atthe University of Minnesota. His researchers come from around theworld, but with heavy representation from China.

Auburn has already developed a hybrid of the blue and thechannel catfish. Growers currently raise channel catfish, but thehybrid fish are more resistant to disease and can survive inlow-oxygen water.

They also swim higher in the water, like blue catfish, insteadof staying at the bottom of the pond, like channel cats. That makesthem easier to catch.

“We want catfish that are dumber so they are caught moreeasily,” Jensen said. Channel catfish avoid nets at harvest time,so the harvest takes longer and requires more effort.

Grafting Genes During Fertilization

The easy-to-catch hybrids, however, are difficult to produce.Channel cats and blues don’t naturally breed with each other.Genetic engineering could allow scientists to create a species withdesirable genes of both fish.

When scientists understand which catfish genes are associatedwith resistance to disease or with rapid growth, they can use DNAto identify the best fish and breed them. They could also graft thedesirable genes onto a catfish’s DNA during the fertilizationprocess.

When a new batch of mapped genes is posted, Liu gets inquiriesfrom researchers around the world interested in his findings.

“You can sense the impact,” Liu said, “It ricochets aroundthe globe.”