A Louisiana pond in Prairieville was found to contain thousands of dead fish on June 18. A resident initially thought the dead fish were goose feathers due to the high volume of fatalities. An inland fisheries technical advisor from the Louisiana Department of Wildlife and Fisheries stated that when oxygen levels in water decrease, fish struggle to breathe. On hot days, fish kills can occur. Conversely, rainstorms may cause the water to turn over, resulting in lower oxygen levels from the bottom entering the water.
The recent fish kill happened in a comparably small pond, which led some to wonder whether an excessive amount of chemicals within the water or overpopulation were to blame for the event. Fish kills are relatively common, but many factors contribute to their occurrence, making the phenomenon complex to decipher. Environmental changes including temperature, acidity, dissolved oxygen, and salinity can all cause issues, and getting to the root cause can prove challenging.
Some experts point to excessive algae growth, which can cause oxygen levels to decrease within the water. This happens when waters contain excessive nutrients, leading to harmful algal blooms. As the blooms decompose, they can take oxygen from the water, putting marine life in peril. Fish kills often happen during the summer when temperatures increase, lowering dissolved oxygen levels and making it difficult for fish to breathe.
Andre Boustany from California’s Monterey Bay Aquarium states that as waters continue to warm due to climate change, fish kills will likely become more common. Fish are endothermic, which means they have the same temperature as the water around them. As water temperatures rise, so does the metabolism of the organism, requiring more oxygen. In summary, fish kills are a complex phenomenon with multiple causes. Although some factors are neither lethal nor dangerous in and of themselves, their combination can lead to fish fatalities.
