Description: Blue-green, black, brown, and dark green; filaments are similar in size to coarse hair and mats are a tangle of filaments, slimy or coarse; toxin and taste/odor producer; smells dirty/fishy. Forms benthic and surface mats.
Similar Mat Forming Blue-green Algae: Phormidium, Scytonema, Leptolyngbya (finer mats, tan color)
Control Method Needed: Captain
Description: Blue-green, brown green, lime, orange; can have an earthy musty smell; unbranched, filaments that typically form mats; can form sheets/films on surfaces of many types of materials (sediment, rocks); some species are planktonic; toxin and taste/odor producer.
Pithophora (horsehair/cotton algae)
Description: Course, tough mats; filaments branched; dark akinete cells; feels similar to a bundle of cotton. Forms dense, dark green mats along the bottom and surface.
Similar Mat Forming Green Algae: Rhizoclonium (rarely branched), Cladophora (Blanket weed)