Pond Dynamics and Balance

Wildhaven pond in August

Three Reasons to Manage Ponds

• control water quality• improve fishing• attract wildlife

Water Quality

Dissolved Oxygen – the oxygen in water that fish & other aquatic organisms can use.

Wind on Surface

What causes this fluctuation in the amount of dissolved oxygen in the water?Who is using the Oxygen at night? Why does it go up in the day time? What happens to largemouth bass and bluegill if it falls below 4 ppm?

4 ppm

10 ppm

Why does warm water have more energy than cold water?

Where does that energy come from?

Why would cold water hold more dissolved oxygen than warm water?

How would the reduced DO (dissolved oxygen) affect fish & plankton?

pH

Good pond pH – 6.5 <---> 9

Alkalinity

Although alkalinity and hardness are different – when looking at the effects of CaCO3 (calcium carbonate) we will treat them the same because the organisms in the pond respond the same. Hardness and alkalinity should be maintained at about 20 ppm.

Ponds with low pH, alkalinity, and hardness should be limed based on soil tests of the pond mud. One to five tons of lime is added per surface acre (surface of the pond water).

Plankton – means floater

•All microscopic and near microscopic life that floats in water.• Divided into phytoplankton (plant) and zooplankton (animal) groups.• Phytoplankton (microscopic algae) are the base of the pond food chain.• Managing phytoplankton through

fertilizing and liming (if necessary) is the key to producing healthy and abundant fish populations. • How would muddy water

affect a healthy phytoplankton bloom?

• How would fertilizing the pond affect a healthy phytoplankton bloom?

• Too much fertilizer? Good or Evil?

Carrying Capacity – anyone?

How could you be sure a predator – prey balance was maintained in your pond?

Stage 1 - deep water – little vegetationStage 2 – shallow water – submerged & floating plantsStage 3 – very shallow water or wet ground with emergent plantsStage 4 – ground becoming drier and plants similar to surrounding area becomes dominant

Stage 1Stage 2Stage 3Stage 4

To help you remember: How do ponds start out? End up?

largemouth bass & bluegill

Management Practices: 8. Decrease creel/season limit 10. Fertilize ponds 12. Fish survey 16. Increase creel/season limit 17. Livestock grazing management 23. Ponds/lake, artificial reefs 24. Ponds, clear muddy water25. Pond construction 26. Ponds, diversion ditch 27. Ponds, deepen edges28. Ponds, remove trees near dike 29. Ponds, repair spillway 30. Ponds, reseed spillway 31. Ponds, restock 32. Ponds, stop leaks 44. Water control structures