Louisiana Department of Wildlife and Fisheries Warns of Potential Fish Kills Throughout the State

Share This:[Sassy_Social_Share]

Published June 17, 2022

Louisiana Department of Wildlife and Fisheries Warns of Potential Fish Kills Throughout the State

On June 16, 2022, the Louisiana Department of Wildlife and Fisheries reported a rash of fish kills in the state’s central and southern regions, caused in part by a combination of high temperatures and storms. The combination of conditions is causing hypoxia, or a lack of oxygen in the water, which according to the LDWF will result in more fish kills.

Here’s how the unhealthy condition manifests itself. Because high-temperature water has a low dissolved oxygen carrying capacity, it creates a delicate balance between oxygen-producing and oxygen-consuming aquatic life. When that balance is upset, the scales can tip in the wrong direction, resulting in a hypoxic (low oxygen) fish kill. Stagnant water, rainfall, extended cloudy weather, decaying debris/vegetation, turbid runoff, and nutrient-laden runoff are all factors that can tip the scales in the wrong direction.

Thunderstorms with high winds and/or heavy rain can also mix the hypoxic water and sediment in the bottom layer with the higher oxygen water in the top layer, lowering the oxygen levels in the entire water column to levels that some species may not be able to tolerate. Because different species and sizes of fish have different tolerance levels for hypoxia, fish kills can sometimes only affect certain sizes and species of fish while others survive. If possible, pond aeration can help to alleviate hypoxic conditions and aid in the decomposition process after fish kills.

Heat and storms have caused fish kills in Louisiana since before recorded history, and the ecosystems have evolved to be resilient and recover from them. Microbes, crawfish, crabs, fish, alligators, turtles, raccoons, and birds are among the decomposers and scavengers that will help clean up fish carcasses.

Many fish and aquatic organisms will seek refuge from the hypoxic waters and survive to participate in the ensuing boom year of reproduction, as there will be fewer predators and more resources available by next spring.

According to the Louisiana Department of Wildlife and Fisheries, while fish kills are shocking to witness and can appear devastating, they often result in a rejuvenated system that is healthy and naturally replenished in the years that follow. LDWF Inland Fisheries biologists monitor and manage many waterbodies across the state and can recommend stocking after a storm if necessary, but fisheries will usually recover naturally if we give them enough time. As a result, unless the situation is extremely unusual, stocking is usually not warranted.

Follow this link to visit the fish kill web page for information on how to report a fish kill and more information on the causes of fish kills.