Baitfish Have Moved Away From Reservoir’s Turbines

Tests conducted Monday at Thurmond Lake indicate blueback herring that have congregated for the past week near the dam’s turbine intakes have moved to other areas where they are less likely to be sucked through the dam and killed.

The tiny baitfish prefer cold, oxygenated water and typically move around in search of preferred habitat. When that habitat coincides with turbine intakes 70 feet below the lake’s surface, fish kills occur and hydropower generation must be halted.

An estimated 44,500 fish were sucked through the turbines last week, bringing hydropower production to a halt for four consecutive days, said Jamie Sykes, the Corps’ district fisheries biologist.

“At this point we haven’t had to stop generation since Thursday, and the tests we did found very few fish in the forebay and the area adjacent to the dam,” he said.

When the fish kills began Aug. 13, the dissolved oxygen level near the turbine intakes was above 2 milligrams per liter, which attracted the fish.

On Monday, oxygen levels had declined by about half – to less than 1 milligram per liter, Mr. Sykes said.

Although the problem appears to have resolved itself, biologists will continue to monitor the turbines whenever they are in operation, he said.

Blueback herring are a preferred forage fish for open water predators including hybrid and striped bass. Estimates in past years have placed the lake’s herring population at 68 million.

Similar fish kills occurred at the lake during similarly hot weather in 2004 and 2006.

Reach Rob Pavey at (706) 868-1222, ext. 119 or rob.pavey@augustachronicle.com.

Originally published by Rob Pavey Staff Writer.

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