Water Hyacinth in Lake Tana
Biomass survey of water hyacinth helps to show major morphometric characters and biomass of the weed. Typically, the biomass of water hyacinth was collected using quadrats with a specific unit area placed over the plant mat (Robles et al., 2015). Water hyacinth samples were collected once via quadrant having an area of 0.5m2. For this study, a destructive biomass estimation method was used to collect the samples. The samples of the weed were measured to estimate the morphometric characteristics of water hyacinth in the study area. Morphometric characteristics of a randomly selected single water hyacinth plant was measured from each quadrant (Robles et al., 2015). The data collection was held twice at October and May when the peak and down water hyacinth infestation occur, respectively. Tape meter was used to measure leaf length, root and shoot length of water hyacinth sample while leaf blade area of the weed was estimated via ImageJ 5.3 software. In addition, the weight of each quadrant was measured using weight scale to capture wet biomass of water hyacinth. According to Madsen (1993) water content of water hyacinth biomass can be dried with a minimum of 500C for considerable enough time. Hence, the weed was dried in an oven at 650C (Center and Spencer, 1981) for 48 hours to remove all the water from the water hyacinth.