Succession of marine algae community around coastal structure

Recently, when the coastal structure is constructed, the creation of the marine algae community on the structure is required. Such structure has been constructed also in Hokkaido. We monitored the transition of the marine algae community on the structure after the coastal structure of the Samani fishing port and the Urakawa port had been constructed for a long term. We observed the seaweed distribution on the coastal structure and on a rocky shore near structure, took a picture of the video, and measured the seaweed coverage and weight. Moreover, we identified the seed of the attached organism, and counted them. We compared the results of the Samani fishing port with the results of the Urakawa port. In the Samani fishing port, Laminaria angustata is dominant during three years after constructing the coastal structure as well as a rocky shore region. However, perennial seaweeds such as Tichocarpus crinitus and Ptilota filicina changed into Laminaria angustata. And they were dominant. Laminaria angustata on the rocky shore was large, and they on the structure were small. In the Urakawa port, the amount of the seaweed on the coastal structure increased up to the same amount as the rocky shore region during one and a half years after having constructed the coastal structure. Afterwards, the attached appearances of the seaweed on the coastal structure kept stabilizing. Laminaria angustata on the structure was large as well as the one on the rocky shore. The findings of the Urakawa port were different from those of the Samani fishing port. It was thought that the difference of the wave environment between the Samani fishing port and the Urakawa port affect these results.