Additionally, the reduction of photosynthesis in the water at night or during cloudy days will further lower the dissolved oxygen in the water, increasing the odds of a fish kill even more.
Before you become too alarmed, it is important to remember that fish kills are natural events and are most often just a correction of a waterbody's natural imbalance. When a lake or pond’s water quality becomes unbalanced, just a small change can be enough to stress fish. Most fish kills occur after several days of cloudy weather, early in the morning, or after heavy rain events. The reason for this is because when sunlight is not present, plants actually use oxygen (respire), leaving less in the water available for fish.
A large rain event can also rapidly circulate the water in a lake or pond causing changes in the position of oxygen rich water in a short period of time. This quick ‘turnover’ of the water can rapidly limit the amount of oxygen available to fish and result in a fish kill.
Keep a close eye on the fish in your waterbody during the summer months to determine if your fish are stressed and may be susceptible to a kill. When oxygen levels are low, the fish in the pond will hang out near the surface of the pond. The fish will be very skittish and stressed out. One big give away is when dozens of fish all get startled at once as you approach the pond. Once oxygen levels reach into the lethal range, it will likely take several days to kill the entire fish population. This gives lake and pond owners a chance to aerate with surface aerators and add water from a neighboring pond using a siphon or pump. Although it is not always practical, sometimes with enough notice the severity of a fish kill can be reduced by notifying an aquatics expert and taking corrective actions.
Proper lake and pond management will greatly reduce the chances of a fish kill due to low dissolved oxygen levels. But, in some cases, a lake or pond may be so naturally imbalanced that there is nothing that can be done to alter the grand design of Mother Nature. It's important to manage not just the lake or pond, but the entire surrounding watershed in such a way as to limit the water quality issues that will otherwise lead to these scenarios. Installation of floating fountains or submersed aeration systems is one way to help distribute dissolved oxygen throughout your waterbody. The addition of a beneficial vegetative buffer is another way to reduce the likelihood of a fish kill. A buffer of beneficial plants will filter runoff and keep unwanted nutrients from entering your lake or pond. Keeping aquatic vegetation and algae within acceptable densities and limiting the amount of nutrients that run off from the surrounding areas are also ways to reduce your chances of a fish kill event.
Contact the experts at 888-480-LAKE (5253) for all of your lake, pond and fisheries management needs.
SOLitude Lake Management is committed to providing full service lake and pond management services that improve water quality, preserve natural resources, and reduce our environmental footprint. Lake, pond and fisheries management services and consulting, and aquatic products are available nationwide. Learn more about SOLitude Lake Management and purchase products at www.solitudelakemanagement.com.