Four dominating submerged macrophytes (Cerato- phyllum demersum L., Elodea canadensis L., Myriophyllum verticillatum, Stratiotes aloides) were collected by hand or with a hook from Tanumah pond, Southwest of Saudi Arabia during April and May, 2008. Tanumah pond is about 2000 m2 in area and located 120 km North Abha city (19 10 N, 42 04 E) and found below a dam (Al-Dahnaa dam) which provides the water into this pond. The pond is sur- rounded by plant vegetation dominated by mosses and some angiosperm plants. It contains submerged macro- phyte bed. The submerged plant material (stems & leaves) with epiphytes was collected at 5 different sites (5 repli- cates each) throughout the pond. The distance between 5 sites was about 20–30 m. The epiphytes were removed from shoots (stems and leaves) of each macrophyte by scraping with a sterile razor blade and the scrapings were placed in sterile polyethylene bottles containing 100 ml distilled water. The bottles were completed to 200 ml with rinsing water used to remove the remaining epiphytes from the scraped parts of each plant. The suspension was vigorously shaken and/or gently homogenized and divided into four portions; one for pigment analysis, one for toxin determination, one for isolation of epiphytic cyanobacteria and one was preserved in Lugol’s solution for counting and identification. The surface area of the plant parts was calculated by measuring the diameter and the length of stems, and drawing the contour of the leaves onto the graph paper, while both leaf sides were considered.