Fish kills that occur in the spring can be deceiving — often, these fish actually die off over the colder winter months. When snow and ice cover the surface of your pond or a portion of your lake, sunlight is blocked out.
When sunlight is blocked out, aquatic plants die and no longer give off the oxygen they would otherwise produce through photosynthesis. And these dead plants feed bacteria within the pond, which go on to further use up the oxygen in the waterbody. As a result, there often is not enough dissolved oxygen within the pond or lake area to maintain fish populations throughout the colder months, even though fish use less oxygen in the winter. Luckily, there are several things you can implement not just to prevent winter fish kills from happening in the first place, but to help promote the overall water quality of your pond.
The biggest and most natural way is by installing fountains, aeration system and water circulators , all aimed at exposing the waterbody to air and allowing oxygen to diffuse into its water as well as continuously circulating the oxygen throughout water columns.
The number of, strength of, and position of these units may vary depending on your pond size or climate. Likewise, depending on your waterbody, it may be recommended to centralize these around a shoreline for safety rather than in the middle of the waterbody where people or animals may fall through and become trapped. Our experts at Clarke Aquatic Services have years of experience working with a vast variety of ponds, lakes and communities and take away the stress and time dedicated to planning and implement the correct deicing solution.
Clarke consultants work to properly assess and install deicing systems that will work with the unique needs of your community — from initial assessment to ongoing maintenance. To learn more, contact our team here , or check out other articles such as:. What is a Fish Kill? Introduce aeration Once DO levels reach a lethal range, it may take several days to kill the entire fish population.
This gives lake and pond owners a chance to circulate the water with floating fountains and increase DO with bottom diffused aerators , nanobubble technology, or oxygen saturation technology. The increased DO can rapidly help restore balance to the aquatic environment. Manage algae and vegetation growth When nuisance aquatic plants like duckweed, watermeal, and hydrilla are left unmanaged, they may form dense blooms or mats on the surface of a lake or pond, blocking sunlight, impeding water circulation, and depriving native species and fish of necessary oxygen.
Physically removing these plants can help free up the water column. Likewise, nutrient management tools like biological augmentation and phosphorous-locking technologies like Phoslock and Biochar can help eliminate excessive nutrients in the waterbody that are known to promote undesirable growth.
Establish a beneficial buffer The addition of a beneficial vegetative buffer is another way to reduce the likelihood of a fish kill through nutrient reduction. Installing a buffer of beneficial plants along the shoreline will help filter runoff and keep unwanted nutrients in the form of fertilizer, trash, pet waste, and grass clippings from entering your lake or pond.
Buffers also prevent nuisance wildlife and geese from entering the waterbody. Keeping aquatic vegetation and algae within acceptable densities by limiting nutrient sources and the resulting runoff is an essential step to help prevent future fish kills.
Test water quality Lake and pond owners often wait until after a fish kill occurs to conduct water quality tests, but a proactive water quality testing program can help identify water quality impairments, like dissolved oxygen, pH, and nutrient levels, before they get out of hand and ensure the most effective management methods are being utilized to protect the waterbody.
Company Name. Designed and Developed by Peak Seven. Webinars Free Reports. Webinars Free Reports Call Us. Fish often fall prey to predators and even may cannibalize their own kind.
Some fish are fortunate enough to escape attack but remain scarred from the encounter. The most common predators that scar fish in stormwater ponds are ospreys, seagulls, herons, egrets, cormorants and anhingas, alligators, turtles and otters. These animals sometimes remove scales, cause scratches and puncture wounds, and trim or shred fins as they attempt to catch fish. Fish also may develop wounds from bedding activity.
This is most evident as redness or scars on the lips and bottom of the tail fin. Springtime Bream Death In the springtime, a peculiar type of death occurs most often with large bream, although it can happen with other species too. In March or early April, residents around ponds may report seeing a few large bream with large, gaping wounds on their sides, but they rarely see more than 10 fish per acre with these symptoms.
This type of kill is most likely the result of winter stress and cannibalism. Over the winter, food resources are limited and the fish become stressed and malnourished. This affects the largest bream the most. As temperatures begin to warm in the spring, the fish become more active and sometimes attack each other.
The pecking combined with malnourishment makes the fish vulnerable to infection and necrosis, which ultimately overcomes them. This type of bream death is more common in ponds that are overcrowded. If you get reports that small numbers of large bream are dying with large wounds in early spring, it is likely due to cannibalism. This will pass as the spring progresses and will not have a significant effect on the fish population.
Mangled fish and bones on the bank is almost always an indication of an otter. Most other predators either ingest the entire fish alligators, herons or take the fish away from the pond to feed osprey. Otters tend to enter and exit ponds in the same place forming a worn-down slide, and they tend to feed on their catch in the same places on the bank. Otters are somewhat messy eaters and leave behind scraps and bones after they have fed.
They also have distinctive feces. Otters do not pose a significant threat to fish populations, except where ponds have been stocked with triploid grass carp. Otters may preferentially remove triploid grass carp from stormwater ponds.
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