Fish deaths in the thousands have been observed at a Minnesota border lake, according to recent reports. At least 2,000 fish were found dead at Lake Traverse earlier in March, and the discovery of the mass fish kill coincided with significant ice melt during the aftermath of the recent North American winter season. The phenomenon seems a mystery but local authorities linked the deaths to an infection called gas supersaturation trauma.
Fish kill is an event that occurs in both freshwater and saltwater ecosystems. It can be triggered by natural and anthropogenic factors. A previous study shows that the most common cause of mass fish deaths is lack of oxygen, according to researchers in the United States. However, the past several decades witnessed the emergence of river pollution, ocean warming, and extreme drought events that contribute to aquatic animal deaths.
Lake Traverse Fish Kill
(Photo : Photo by Jack Charles on Unsplash)
The Lake Traverse fish kill involved 2,000 to 3,000 deaths that were discovered on March 14. The Minnesota lake is located along the border with South Dakota. Local sources reported that initial analysis of the phenomenon likely occurred due to mild temperatures in the area over the past winter season. Meanwhile, local officials linked the fish deaths in the lake to the infection or environment-related condition mentioned earlier.
Gas bubble trauma (GBT), caused by total dissolved gas (TDG) supersaturation, can harm fish such as juvenile rainbow trout (Oncorhynchus mykiss), juvenile kokanee (Oncorhynchus nerka), and white sturgeon (Acipenser transmontanus). This is according to researchers who published their study in the journal Canadian Journal of Fisheries and Aquatic Sciences in 2021, where the authors explored the impact of GBT to different fish species.
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Water Pollution
Water pollution coming from different human activities, including commercial and industrial emissions, is one of the many threats that endanger local fish populations in rivers, streams, ponds, and other inland water. Over the past decade, fish deaths have also been observed in coastal areas. In the US, around 12,000 fish suffocated and washed up dead along beaches in southeast Texas, it is reportedly caused by deoxygenation due to warm weather.
Water pollution involves chemicals, waste, plastic, and other pollutants contaminating seas, lakes, rivers, and reservoirs, according to the Natural Resources Defense Council (NRDC). In its 2023 report, the NRDC says this type of pollution degrades water quality and makes it toxic both for humans and the environment. Aside from human-induced water pollution, climate change has also been attributed to the deaths of marine life, primarily through ocean acidification.
In recent years, multiple studies have shown that the anthropogenic climate crisis and global warming are making some marine ecosystems uninhabitable for aquatic animals, including corals, crustaceans, and multiple fish species. Furthermore, previous research has also shown that the continuance of ocean warming could force some marine animals to migrate elsewhere, disrupting the food web or predator-prey dynamics.
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