UF Project Shows Sturgeon Can Be Raised Successfully In Fish Farms

November 5, 1999

BLOUNTSTOWN Researchers at the University of Florida’s Sam Mitchell Aquaculture Farm harvested about 1,800 farm-raised Gulf of Mexico sturgeon this week, completing a 17-month project that shows the threatened fish can be successfully raised in a controlled environment.

In addition to demonstrating that the fish would thrive when raised in tanks, the project also compared the use of fresh well water and recirculated pond water system and found that each system has its advantages.

Andrew Lazur, an aquaculture specialist with UF’s Institute of Food and Agricultural Sciences, said one goal of the project was to evaluate sturgeon as a candidate for the Florida aquaculture industry.

“We want to see if it’s an alternative species for our producers,” Lazur said. “The reason we’re looking at sturgeon is that it’s a high-value food fish. Sturgeon can bring about $4 a pound, so obviously from a farmer’s standpoint it is very attractive.”

By comparison, Lazur said farm-raised catfish earns about 75 cents a pound, and even the more expensive hybrid striped bass can yield only up to $2.50 a pound. However, Lazur said the next step is an economic analysis to determine if the price farmers could expect to get for the fish on the marketplace will be greater than the cost of raising the sturgeon.

Gulf of Mexico sturgeon “fingerlings,” young fish weighing an average of 6 grams each, were placed in six 20-foot-diameter tanks. Three of the tanks used a flow-through system in which fresh water from wells on the farm site was constantly pumped through the tanks. The other three tanks were fed with water from a large pond that also served to clean the water before it was recycled back into the fish tanks.

Deborah Britt Pouder, a UF biological scientist who co-directed the project with Lazur, said the challenge was determining the methods that would result in good fish growth that would be cost-effective for farmers to implement.

“We’ve had to change things probably every day,” Pouder said. “We’ve gone out and tried one system, and if something didn’t quite work then we changed it. It’s been a big progression the whole way.”

Problems ranged from initial solids accumulation in the tanks to levels of oxygen that were too low for the fish during the summer months. Pouder said the pond also created some challenges of its own.

“We’ve had some incredible temperature swings throughout the year and were seeing a big influence on our fish growth,” Pouder said. “When we got to the heat of the summer, the pond just couldn’t keep them going. Everything they were eating was going to maintaining body weight and not going to growth.”

Pouder said at one point the fish in the pond water tanks were about half the size of the fish in the tanks fed by the flow-through system. Lazur said that while the flow-through system appears to be better in terms of fish growth, the pond-recirculation system still has its advantages.

“From a production standpoint, the flow-through system is more attractive. The yield is significantly greater and the industry can easily adopt it,” Lazur said. “But the pond-recirculation system is a zero-discharge system to the environment.

“We may have to modify the pond recirculation system in some fashion, cooling water down in summer and heating it up in winter by some means. It has to be economical,” he said.

The sturgeon harvested this week did not end up in the frying pan; rather they were transferred to a pond at the aquaculture farm. Currently, Gulf of Mexico sturgeon cannot be sold commercially because they are listed by the federal government as a threatened species.

“We’re trying to get an exemption to allow the use of captive brood stock for commercial aquaculture,” Lazur said. “We may then use brood stock to produce fingerlings to distribute to industry to jump start sturgeon aquaculture in Florida.”

Lacking an exemption, Lazur said, researchers next will look at the Atlantic sturgeon, which is a close relative of the Gulf of Mexico sturgeon. Lazur said the Atlantic sturgeon might have all the same qualities as the Gulf of Mexico variety.

“The efforts now are to evaluate a variety of species that are commercially viable,” Lazur said. “Atlantic sturgeon may be one. We have a lot of information on the Gulf of Mexico sturgeon and they’re basically the same fish.”