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Fry production and genetics Hybrid catfish research advancing

Researchers at Auburn University have studied hybrid catfish for decades and, for nearly as long, have known it's an outstanding food fish. While it may not be a silver bullet for what ails the catfish industry, the hybrid is capable of greatly enhancing production, sustainability and profitability for U.S. producers.

“The hybrid is a fabulous fish for pond culture,” says Rex Dunham, Auburn professor. “They don't do well in cages or small tanks. But for the traditional pond farms, they're a vast improvement over channel cats.

“One of our goals is, within five to 10 years, to have a majority of the catfish industry utilizing the hybrid.”

To that end, Auburn's research is focused in two areas:

  • Producing fry. Dunham says the reason hybrids aren't already more widespread is the difficulty to getting the two species — channel catfish and blue catfish — to mate. “We've worked every year trying to improve the technique for artificially producing these hybrid eggs.”
  • Genetics. “Even though the hybrid is a great fish, it isn't perfect. So, we're working on selective breeding to develop lines of channels and blues that, combined, make increasingly better hybrids.”

Roger Yant graduated from Auburn in 1975 with a master's degree. His post-graduate research and thesis were on hybrid catfish.

“I guess that's a long time to be interested in the hybrids,” says Yant, who runs Hybrid Catfish Company, a hybrid fingerling operation near Inverness, Miss.

Yant has taken a winding road to his current job. After managing a catfish processing company and trying his hand at farming, Yant went to work for Gold Kist, a large Atlanta-based farmer co-op, in 1990. At that time, Gold Kist was the second-largest U.S. poultry business and was interested in diversifying into aquaculture.

In the modern poultry business, a segment in the chain is called “primary breeders.” These breeders produce the chicks taken to large poultry houses to grow out. Because of their work in genetics, the poultry industry made huge jumps in efficiency.

Gold Kist figured Yant could help do the same with catfish. “We made a lot of progress at that until about 2001. After about 10 years, Gold Kist moved towards becoming a stock company, so they decided to get rid of everything but poultry. It's too bad, because they'd decided hybrids would be something to concentrate on in the breeding program. So we put a lot of emphasis on it and were close to solutions for the common hybrid problems.”

Gold Kist sold its breeding facility to Harvest Select, based in Tuscaloosa, Ala. Paul Bryant Jr. — the legendary Bear's son — is an owner, and the company has farms and processing facilities in Alabama, Mississippi and Arkansas.

“I stayed with Harvest Select, a more vertically integrated company, until a couple of years ago when I set up the fingerling company. Now, the company wants our Inverness operation to produce hybrid fingerlings to be grown out in its farm ponds.”

Once hybrid fry are produced, there are few troubles with the fish — they grow well and survive well. But currently, securing fry economically is a major, delicate, time-consuming task requiring hand-stripping and the death of parent fish.

“I'd guess the industry processes around 300 million to 400 million fish every year,” says Yant. “We produce about 1.2 billion channel catfish fry. That shows the survival rate from fry to processing plant is low — mostly due to disease, birds, what have you.”

Even though hybrid survival rates are much better than that, “we still probably need 500 million hybrid fry annually. But the industry produced, maybe, 25 million hybrid fry (in 2006).

“Back in the 1970s, we thought it was a big deal to have 10,000 head of hybrid. By the 1990s, we were up to a million or two million. Even then, though, it's a far cry from what the industry needs if hybrids are to catch on.”

It is possible for channels and blues to mate without outside intervention. Neither Yant nor Dunham are enthusiastic about that approach, however.

“I don't think that's a wise place to put our resources,” says Dunham. “We studied that a lot in the past. And we thought we had solved the puzzle, that we had found lines of blues and channels that would mate reliably.”

Auburn researchers had good luck with those lines for two years. The third year their luck turned.

“You can't operate a farm under that sort of uncertainty,” says Dunham. “A grower can't afford a year with a fingerling wipeout. But with artificial fertilization — hand-stripping techniques — we can nearly guarantee fry will result.”

Long-term it would be “fantastic” to find fish strains or lines that, year after year, would mate to produce a hybrid. But to make this work in the short-term, “artificial fertilization is the only way to go,” says Yant.

As for meeting the goal of converting the industry to majority hybrids, “part of the challenge is this is a newer technology,” says Dunham. “That means there's a time lag to scale up for the hybrids.

“The other part is that even though farmers who have tried hybrids have had positive experiences, adoption will take a little while because many people need proof positive about the hybrids, and well they should. They need to see a track record of good performances that leave little doubt this fish will benefit them. That will come.”

Yant believes in the same, patient approach. “Most of my customers this year wanted to try a pond or two to see how they like the hybrids. And that's smart — I don't think I'd jump into something like this without a feeling out period.

“But I think they'll have a good experience and want to order more. That's what I've found over the years — farmers who try these hybrids typically come back for more.”

It's true the hybrid is a better animal, says Yant, but management techniques may need to change to maximize its potential.

“We're still learning what those changes are. For example, farmers are familiar with topping. In a given pond, not all fish are ready for harvest. We go in with a special net that allows the fish less than a pound in size, say, to escape back into the pond. We send the larger fish to the plant.”

One of the problems with the hybrids, it's difficult to do such partial harvests. The biggest part of the channel cat is the head.

“If it can get its head through the net, it can get through. The hybrid, though, is taller — there's an area behind the head that's actually the largest part of its body. That means the hybrids don't grade through the seine like channels do. And that means you can unintentionally harvest hybrids that aren't ready to go to the plant. We've got to find a way to work with, or around, that.”

Pressures on U.S. aquaculture from Asian fish imports are helping fuel the need for hybrids.

“Whenever you have threats to sustainability and profitability, it makes development of improvements all that more urgent,” says Dunham. “That said, even without those international developments, we'd be putting forth the same effort. Even if economic conditions were better for the catfish industry, the hybrid still makes huge economic sense.”

Now that the Chinese are pond-raising catfish, what would prevent them from appropriating any hybrid research breakthrough?

“Oh, we've thought about that,” says Dunham. “The Chinese are smart people and the hybrid would benefit them, like it will us. What we need to do is continue to make advancements in genetics, in hybrids, in disease control, water-quality management. We need to do everything we can to stay a step ahead of them. Research funding is absolutely critical for that.”

Hybrid fingerlings cost more because “it's a lot more work to generate them,” says Yant. “But if they weren't working well, there wouldn't be such high demand for hybrids.”

How much of a difference can hybrids make?

“A few years ago, we did an economic analysis on a company with ponds in both hybrids and channel catfish production. Obviously, the numbers have shifted since then, but at the time we could lower food fish production costs by 7 cents per pound by going with hybrids. And those savings are after accounting for the more expensive hybrid fingerlings.”

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