Methods for monitoring baseline populations for seaweed communities We monitored seaweed communities along the Korean coast, including Jeju Island, to estimate a baseline for natural beds. Ten core sites were evaluated for three years (2006-2009) and another 20 satellite sites were surveyed for one year only. A total of 64 sites were seasonally surveyed in July, October, January, and April from the subtidal to the splash zone. Conventional methods were applied. To estimate the seaweed biomass or standing crop, we adopted a nondestructive technique. Based on the percent coverage and weight of dominant species within a community, we were able to obtain species-specific regression equations between coverage and biomass for each dominant species (Ko et al. 2008). In the case of kelp with long and tall fronds, data for density and individual sizes were required. At each sampling site, five replicates of 50 ´ 50 cm quadrats were assessed in the intertidal, upper, middle, and lower zones, at subtidal depths of 1, 5, and 10 m. Each community was categorized overall into five size classes, based on average standing stocks: Class 1, > 2400 g m-2; Class 2, 1800 ~ 2400 g m-2; Class 3, 1200 ~ 1800 g m-2; Class 4, 600 ~ 1200 g m-2; and Class 5, < 600 g m-2. From this analysis (densities shown in Fig. 3), we determined that the coast of Jeju Island had the largest average size class at 1.8, followed by 2.9 for the southern coast (Choi et al. 2008a; Kim et al. 2008), 3.2 for the eastern coast (Kang et al. 2008; Shin et al. 2008), and 5.0 for the western coast (Choi et al. 2008b; Wan et al. 2009).