Turbidity Effects on Fish and Aquatic Life
The significance of excessive turbidity in water on fish and other aquatic life begins by modifying the temperature structure of lakes.
Bottom temperatures are generally lower in turbid lakes or ponds than in clear ones. In many lakes, lower temperatures means lower productivity. Turbidity also interferes with the penetration of light. This reduces photosynthesis and thereby decreases the primary productivity upon which the fish food organisms depend. As a consequence, fish production is reduced.
For example, productivity of farm ponds and hatchery ponds.
Clear Intermediate Muddy
Ponds Ponds Ponds
Average turbidity, units less than 25 25-100 over 100
Fish yield, lbs per acre 161.5 94 29.3
Ratio of volumes of net plankton 12.8 1.6 1
In reservoirs, average volume of plankton in surface waters was 13.8 times greater in the clear reservoir than in the turbid one. Also, by excluding light, turbidity makes it difficult for aquatic life to find food. Conversely, some organisms may be similarly protected from predators.