While officials await the results of water quality tests regarding the Ogeechee River, the question of why fish are dying downriver from a local textiles plant — but not upriver — remains unanswered. When about 38,000 fish died in the Ogeechee River in May 2011, the cause was ruled to be columnaris, a bacterial disease caused by environmental stress. The dozen fish found dead this Memorial Day weekend died of the same bacterial infection, according to Environmental Protection Division officials.