Fish Kill Reported at Bantam Lake

On Thursday, August 23rd James Fischer and I traveled to the North Bay area of Bantam Lake following reports of dead fish washing up on shore. We walked approximately 75 yards along the edge of North Bay and found several species of dead fish in varying degrees of decay. Most of the dead fish were Sunfish, but we also saw Largemouth Bass, Brown Bullhead, Tench, and White Perch. Since we did not see a large quantity of dead fish, this fish kill was likely due to natural events, such as the record high temperatures we’ve had this summer. When a lake heats up, water holds less oxygen. Therefore during a very hot summer, oxygen levels decline, creating stressful conditions for fish. Also, if shallow waters become too densely occupied by fish, these areas can become more susceptible to disease outbreaks. High levels of turbidity could also be to blame. Turbidity is the haziness of water caused by suspended solids, which can affect the ability of fish gills to absorb oxygen.

A Sunfish that just washed on shore. 
A heavily decayed Largemouth Bass.


Fish kills that are natural and localized are typically no reason for alarm, but tests still should be done to test if levels of toxicity exist. CT DEEP Fisheries Biologist, Ed Machowski concluded that warm water temperature, low oxygen levels, and algae blooms are causing the fish stress. The algae bloom is limiting light penetration, therefore affecting photosynthesis and causing oxygen levels to drop. Dead fish were found at several regions of the lake, but most were found at the North Bay, due to the southwesterly breeze pushing fish to the northeast section of the lake. It should be noted that the fish kill is not related to the August 15th herbicide treatment on selected areas of Bantam Lake.   

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