NOWPAP Seagrass Distribution Map

Seagrass distribution in the NOWPAP region Map


Waycott et al. (2009) reported 110km2 of seagrass bed has been disappeared annually worldwide. Grench et al. (2012) pointed out that seagrasses in Temperate North Pacific region, which includes NOWPAP region, had a highest vulnerability score among the other regions and three major threats were landfill by urbanization and port development, rise of sea water temperature and rive of sea level. However, the assessment result by Grench et al.(2009) do not have enough information and/or data in the NOWPAP region.Thus, CEARAC started review of literatures on seagrass distribution and threats to seagrass in cooperation with researchers in China, Japan, Korea and Russia.

Researchers cooperated in literature review on seagrass distribution

  • China:Dr. Yang Dingtian (State Key Laboratory of Tropical Ocean Environment Chinese Academy of Sciences)
  • Japan:Dr. Teruhisa Komatsu (Yokohama College of Commerce)
  • Korea:Dr. Jong-Kuk Choi, Dr. Keunyong Kim (Korea Institute of Ocean Science & Technology, Korea Ocean Satellite Center)
  • Russia:Dr. Vasily Zharikov (Pacific Geographical Institute of the Far Eastern Branch of the Russian Academy of Sciences)

Visualization of seagrass distribution

Based on collected information on literatures, distribution of seagrasses is visualized on a Web-GIS Map ( ) on this website with icons. When clicking each icon, more detailed information (location, seagrass species, source of information, and so on) is popped up.

Three icons (A, B and C) indicate different types of seagrass. Distribution size is shown by the size of ‘○’ and the numbers.

Icon A: Seagrasses (zostera and halodule) found on sandy substrates

Zostera marina


Zostera japonica


Zostera caespitosa

Zostera asiatica



Zostera caulescens


Halodule uninervis



No image available





Icon B: Seagrasses (phylospadix) found on rocky substrate

Phyllospadix iwatensis

Phyllospadix japonicus




No image available

Icon C: Seagrasses (halophila) found on sandy substrates 

Halophila ovalis

Halophila nipponica


No image available



Reference materials