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.
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A Sunfish that just washed on shore. |
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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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