Published: July 09, 2009 06:18 pm      

Lack of oxygen believe to be cause of fish kill

PICAYUNE — Reports about a substantial fish kill on Old River have been confirmed, said Jimmy Rayburn, District Six Fisheries Biologist for the Mississippi Department of Wildlife, Fisheries and Parks.

In a phone interview on Wednesday, Rayburn said that the kill was first reported on Tuesday, June 30, by area manager Patrick Rush. Just below Moody’s lake on Old River, a large kill of fresh water mussels was the first indication that the oxygen levels were severely low. Witnesses said the river turned white with the decaying mussels.

On Wednesday, Rayburn and Rush conducted a survey and took photos of the kill as it continued to move down river. “When I saw the amount of fish dying, we had to contact DEQ to investigate to ensure that the kill was of natural origins,” Rayburn said.

On Thursday, the Department of Environmental Quality joined in the investigation with Rayburn and Rush. Water samples and photographs were taken to the DEQ lab to be processed. Rayburn said results should be finalized within a couple of weeks but there is no reason to suspect anything but simple oxygen depletion.

“Dissolved Oxygen in the water is what the fish breathe, and with prolonged hot days, low water and limited flow of the oxbows lakes, this is the result." Rayburn said. “The good thing about oxbows and tributaries like Old River is when the Pearl River rises with the rainfall, it replenishes the area. Kills like this is a common, natural occurrence but can stem from several different factors.”

The last reported kill was during Hurricane Katrina when massive amounts of vegetation fell in the river and lakes. When the leaves decayed in the water, it depleted the oxygen and caused a large fish kill. Rayburn said that a lot of the fish they photographed were large, mature fish such as bass, bream and catfish and would not have been able to reach this size since the last fish kill.

“This kill seems to have resulted for the same reason as the Katrina kill, lack of dissolved oxygen, but were caused from different factors,” Rayburn said.