Allman Monograph, 1856

Identification Guide Page 2

Example: Cordylophora caspia

Seldom a problem by themselves, colonial hydrozoans often combine with bryozoans to form a tangled net of fibers that entrap other particles in the water. Large irrigation and water treatment facilities are most commonly affected by this condition.

Hydrozoans

Example: Peritrichs

Under high nutrient conditions, large populations of microscopic protozoans release trillions of tiny threads that clog screens and filters with a felty mass. Often this is accompanied by an offensive odor. Fouled equipment must be either discarded or cleaned by specialized techniques.

Stalked Protozoans

Examples: Plumatella rugosa, Fredericella indica, Paludicella articulata

These are the most common animals to clog pipelines, screens, valves and filters in fresh water. They are often described as “algae,” even though they are normally grey or brown, not green. Depending on growth conditions, bryozoans can resemble roots, moss, or a lumpy, gelatinous material. An Asian species is currently causing the most serious problems worldwide.

Bryozoans