Turbidity

• Refers to the decreased ability of water to transmit light caused by suspended particulate matter in the water column of the pond ranging from colloidal to course.
• Transparency α1/Turbidity.

Causes of turbidity

1. Planktons: is generally desirable in fishponds.
2. Suspended particles of silts and clay: This is generally undesirable in fish ponds.
3. High concentrations of humus substances: May be desirable or undesirable in fish ponds.

Sources of turbidity

1. External sources:

• Surface runoffs, constructions, livestock, rainfall, dike erosion, etc.

2. Internal sources:

• Resuspension of particles
• Fecal material
• Feed, fertilizer, lime, etc.

Effects of turbidity

1. Reduced light penetration
2. Excessive turbidity may interfere with gill function which causes respiration problems.
3. Cause siltation of bottom substrate- reduced pond depth.
4. Adsorbs and desorbs the nutrients of pond water.
5. Affects the vision of fish.
6. Acidifies and sterilizes the water due to humus contents.