Aquaculture for all

Paddlefish plus points for environment and caviar harvest

US - Kentucky State University aquaculture researchers have worked out an innovative way to recycle outdated water treatment facilities, help sewer systems clean water better and grow strong young paddlefish ready for large-scale fish farming.

Dr. Steven Mims successfully raised 40,000 paddlefish in decommissioned wastewater tanks at the Frankfort Sewer Department during the summer.

Young paddlefish in holding tanks

"We used processed water, which has to pass EPA standards. It's near drinking-water quality, not a whole lot different from the Kentucky River water. It's good water," Mims said.

Such treatment facilities often develop persistent problems with an overabundance of the zooplankton "daphnia." Too much zooplankton can actually stir up the tanks and prevent solids from filtering out, jeopardizing water quality.

Turns out, daphnia is what young paddlefish love.

"It's a free food source, plus it's helping the sewer plant," said Dr Mims .

KSU was able to harvest hundreds of pounds of it to feed the paddlefish in their first month. Then they switched to pelleted feed for three months.

The combination has proven so successful that the 4-month-old paddlefish he harvested yesterday are larger and healthier than expected, making them more likely to survive when stocked in lakes.

The paddlefish will be put into municipal water supply lakes around the state, where they can mature and eventually produce caviar and be harvested for boneless meat. "It's a fledgling industry. We see this as an avenue to continue to market this product," Mims said. As sturgeon caviar from the Caspian Sea has become more scarce, prices for paddlefish caviar have risen from about $25 a pound in the 1980s to an average of about $100 a pound today.

Further Reading

- To find out more about Paddlefish production click here.
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