Fish kills expected, but storm has minimal effect on upland animals

Mark Shirley, Reed, Donald P., Gautreaux, Craig  |  9/10/2008 8:08:55 PM

News Release Distributed 09/10/08

Hurricane Gustav caused many problems for people throughout Louisiana, and wildlife also are feeling the effects of the storm.

Fish kills are occurring throughout South Louisiana, and upland animals lost trees that provided food and shelter and have been displaced by floodwaters.

According to Mark Shirley, a fisheries agent for the LSU AgCenter, fish kills are common after events the magnitude of Hurricane Gustav. Vegetative debris blown into water bodies begins to decay and decompose after several days. This decomposition process uses up dissolved oxygen in the water, so fish no longer have the oxygen needed to survive and begin to die.

“Even though the water is moving because of the heavy rains, the oxygen levels are being depleted faster than it will naturally be replaced. Fish kills are inevitable after a storm like this,” Shirley said.

Shirley also cautions that homeowners can experience this same phenomenon in ponds on their property. He recommends that if the pond has the means to be aerated, the process should begin immediately.

“Aerators should be run for the next week or more until the color of the pond returns to a healthy green tint,” Shirley said.

Shirley stresses a chemical test or a dissolved oxygen meter as the only reliable methods to determine the exact amount of dissolved oxygen in the water.

Louisiana’s alligator season also has been influenced by Gustav. Alligator processors were unable to process gators immediately before the storm and for several days after because of power outages.

Shirley says the alligator catch is being affected by the fish kills. “All those dead fish in the water are a buffet for an alligator. They’re not having to look hard for their next meal and are less likely to bite a baited line,” Shirley said.

For upland animals such as deer and squirrels, trees that produce food for them were hit hard. Many pecan and oak trees sustained damaged or were uprooted when Gustav came ashore.

Acorns and pecans also were blown from the trees. While squirrels and deer will have plenty of food on the ground now, much of it will rot before it can be eaten.

According to Don Reed, wildlife specialist with the LSU AgCenter, wildlife is very resilient when it comes to dealing with storms such as Gustav.

“In the short term there will be some adverse effects on wildlife, but they will be minimal. Unless there was widespread habitat loss, animals such as deer and squirrels will simply adapt to their environments,” Reed said.

In looking for a silver lining, Reed says habitat for deer will be better in the coming years. Openings created by fallen trees will allow vegetation to grow and provide deer with “browsing material.” Fallen trees will provide bedding areas for does and their fawns.

Reed says animals displaced by the flooding rains generally will return once the floodwaters recede. If the habitat was damaged too severely by the storm, animals will simply move to another suitable area.

In addition, Reed says litters of squirrels and births of fawns tend to be lower following years in which poor crops of acorns and nuts occurred. A similar pattern may hold true for years following storm events such as Gustav.


Contacts: Mark Shirley at (225) 578-3921 or

Don Reed at (225) 683-5848 or

Writer: Craig Gautreaux at (225) 578-5673 or

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