"The bacteria are dormant when water temperatures fall below 56 degrees, and that's why anglers do not have a problem holding shad in winter. But in warmer months, the bacteria is a problem, so it's important not to stress the shad. Stress is caused by shad purging in the holding tank because their waste clogs gills and sends ammonia levels through the roof."

Parramore has found that shad mortality drops to 10 percent when he catches them in a tailrace.

"In a heavy current, the shad empty out," he explained. "So when you throw a net on them and drop them in your tank, the water remains clean. It makes all the difference."