Tuesday, August 14, 2012

Managing Missouri Fish Ponds During an Extended Drought

Here is a new MU Extension guide sheet titled "Managing Missouri Fish Ponds During an Extended Drought".  The first few paragraphs are below.

Many Missouri ponds are watershed ponds that rely on surface runoff to maintain proper water levels.  Continued drought combined with high temperatures can have devastating effects on fish ponds. Drought conditions tend to reveal poor pond construction and magnify the potential for a fish kill. Even ponds that have been properly designed and constructed within a watershed can have problems.

Ponds that typically are the first to have problems are those in very small watersheds or on marginal soils. A small watershed is one where the area surrounding the pond is too small to provide enough runoff to maintain the pond’s water level during years with average rainfall. In Missouri, the recommended watershed-to-pond acreage ratio is between 15-to-1 and 20-to-1, which means a watershed must be at least 15 acres to provide runoff for a 1-acre pond.

As pond levels decrease through seepage, evaporation and lack of runoff, several problems can occur:
* Fish may become stressed as the pond becomes more crowded and they are confined in smaller areas of water.
* Waste metabolites such as ammonia, carbon dioxide and nitrates become more concentrated, which can further stress and even kill fish.
* Less dissolved oxygen is available for the fish to breathe as they and other aquatic organisms are crowded into smaller volumes of water.
* Unwanted aquatic vegetation and algae begin to grow as nutrient levels in the pond become more concentrated.

Other sections of this University of Missouri Extension Guide Sheet include:
* Pond water level
* Aeration and pond oxygen
* Warning signs of oxygen depletion
* Reducing the chance of a fish kill during a drought
* Fish diseases and stress
* Observe your pond and quickly react to changes

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