HOUMA, La. – Thousands of dead fish are littering bayous in Lafourche and Terrebonne parishes, casualties of oxygen depletion caused by Hurricane Isaac.

The Courier reported the kills, common after hurricanes disturb organic matter in local waterways, are not expected to pose a threat to drinking water supplies.

“We began seeing thousands dead pogie bait and fish of all sizes floating in the water. What alerted me to this were all the seagulls flying in the back of our home,” Janice Hamilton of Montegut said after the fish surfaced last weekend. “They were feasting on all the carnage.”

In Lafourche Parish, kills have been reported from the Assumption Parish line down the bayou to Lockport this week, said Archie Chiasson, manager of the Bayou Lafourche Freshwater District.

Kerry St. Pe, director of the Barataria-Terrebonne National Estuary Program, said thousands of dead fish have been found in area waterways and lakes but added it happens after most major storms and is because of a lack of oxygen in the water.

Storms such as Isaac disturb organic matter on the bottom of bodies of water, St. Pe said. The stirring of this organic matter leads to a greater presence of bacteria, which decomposes the newly stirred material.

“When there is a lot of organic matter, there is a lot of bacteria,” St. Pesaid.

The bacteria then use an inordinate amount of oxygen from the water and that suffocates the fish.