The Louisiana Department of Wildlife and Fisheries (LDWF) says it will investigate each one of the substantial fish kills it predicts throughout southeast Louisiana in the aftermath of Hurricane Ida.
Hurricane-related fish kills are generally caused by low dissolved oxygen (DO), and can occur from landfall of the storm until weeks after the event. The main factors contributing to hurricane-related fish kills include storm surge, the churning up of oxygen-poor water and sediment due to wind and rain, and the sudden input of large amounts of organic debris into waterways.
Following the event, organic matter will begin to decompose, and microbes will deplete the DO from the water causing fish to “suffocate.” These factors can work alone or in conjunction to cause fish kills following a hurricane.
Storm-related fish kills have occurred in Louisiana since before recorded history, and the ecosystems have evolved to be resilient and bounce back from them. Decomposers and scavengers including microbes, crawfish, crabs, fish, alligators, turtles, raccoons, and birds will do their part helping to clean up fish carcasses.
Many fish and aquatic organisms will find refuge from the low DO waters, and participate in the boom year of reproduction that will surely follow since there will be fewer predators and more resources available by next spring.
While fish kills are shocking to experience and can appear devastating, they often lead to a rejuvenated system that is healthy and naturally replenished in the following years.
For information on how to report a fish kill or more information about the causes of fish kills, visit our fish kill webpage.