Good and bad algal blooms

We have already discussed pond fertilization and things that are to be considered during pond fertilization. Today we shall look on algal bloom and it is impact on fish farming business.

Algal bloom refers to as rapid increases in the population of algae in fresh water or water held in a fish pond or marine system and is characterized by discoloration in the water.

From the start, pond fertilization aim mostly on stimulate plankton growth and increase fish production but discoloration of water tends to raise confusion among fish farmers.

Color of the pond water tends to change due to the plankton growth in the pond. It should be noted that these planktons do not all produce the same color, they tend to produce different colors depend on their pigments.

  Causes of algal bloom

Excessive nutrients concentration in the water; Phosphorous and Nitrates are highly demanded by algae for their growth.

High water temperature; warm water tend to favor the growth of algae in number of ways like;

Prevent water from mixing, allowing algae to grow thicker and faster

Warmer water is easier for small organisms to move through and allows algae to float to the surface faster.

Higher Carbon dioxide levels; Algae need Carbon dioxide to survive hence rapid growth.

Good and bad algal bloom

Yes, there are good algal bloom and bad ones. Many people when they hear algal bloom, directly they think of harmful algal bloom.

Good algal bloom

Good bloom tends to form light green water or where you cannot see more than 18 inches.

Phytoplankton is good example of good algae that provide source of food for fish and other aquatic life.

Harmful algal bloom

They tend to produce poison hence kills fish

Appearance

Appear as foam or scum on the surface of water.

Tend to take various color depend on pigments like blue green and red (red tides)

Forms

• Cyanobacteria-Occur mostly in fresh water
• Dinoflagellates-Marine water
• Diatoms-Mostly in marine water

Control of harmful algal bloom

Use of aerator pump air throughout water column to enable mixing of water columns.

Surface skimming; some tend to form surface scums forexample cyanobacteria.

Algaecide :Chemical compound applied to water body to kill cyanobacteria

Control of nutrients accumulation through proper management of fish feeding and prevent water runoff from crops farming

Provide shade  in order to minimize light penetration