Much of Arkansas is experiencing drought conditions. Lack of rainfall can affect farm ponds and fish, said Nathan Stone, extension fisheries specialist at the University of Arkansas at Pine Bluff Aquaculture/Fisheries Center of Excellence.
“Pond water is lost through evaporation and seepage,” he said. “Evaporation alone during the summer may average a quarter of an inch a day, which adds up to more than 7 inches a month.”
Seepage losses vary greatly among soil types and individual ponds, but can equal or exceed losses to evaporation. In ponds used for watering livestock, consumption also rises during hot weather. Cattle can consume up to 20 gallons per animal each day.
“In extreme conditions, ponds may dry up,” Stone said.
The most obvious effect of drought on ponds is that declining water levels will reduce pond area and water volume. Weeds will grow in exposed areas and out into shallow waters. In ponds where organic matter is important in sealing the pond bottom and retaining water, exposing the pond bottom can lead to increased water loss once the pond refills.
Independent reporting for Pine Bluff & Jefferson County since 1879.
“Fish will become concentrated in deeper areas of the pond,” Stone said. “Shallow water becomes particularly hot, and is stressful to fish.”
Fish kills due to low oxygen levels are more likely because hot water holds less oxygen than cooler water.
Long-term, effects of drought and associated reduced pond water volume on fish populations may be positive or negative. Prey and predator fish become concentrated.
“If a pond had excessive numbers of small bream to start with, increased predation can be beneficial,” Stone said.
However, in ponds with balanced fish populations, prolonged low water could reduce stocks of small fish below desirable levels.
Unfortunately, there is little that pond owners can do, other than to keep a close eye on fish ponds and be ready to provide aeration if needed. Also, avoid treating aquatic weeds with contact herbicides during the hot summer months, as decaying vegetation consumes dissolved oxygen and can lead to a fish kill.
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Bobbie Crockett is an extension specialist-communications at the School of Agriculture, Fisheries and Human Sciences at the University of Arkansas at Pine Bluff.