Seagrass habitats in the Arabian Gulf: distribution, tolerance thresholds and threats

Seagrass habitats in the Arabian Gulf constitute a critical marine resource in the region, sustaining a high primary production, harbouring a high biodiversity of associated plant and animal species, and serving as important nursery grounds for penaeid shrimps, pearl oysters and various other marine organisms. The extreme environmental conditions in the Arabian Gulf, with major seasonal variations in water temperature and salinity, are tolerated by only three opportunistic seagrass species (Halodule uninervis, Halophila stipulacea and H. ovalis). Approximately 7,000 km² of seagrass habitat has been mapped in the Arabian Gulf to date, with particularly extensive meadows in the coastal waters of the United Arab Emirates, Bahrain and Qatar. This area also sustains the world's second largest population of approximately 5800 dugongs, which feed almost exclusively on seagrasses. Meanwhile, massive land-reclamation projects and rapid industrial developments (including power- and desalination plants) are posing an unprecedented threat to seagrass habitats in this region. This paper provides a detailed overview of the known distribution of seagrass habitats in the Arabian Gulf and their tolerance thresholds for temperature, salinity, turbidity and sedimentation. The paper concludes with a summary of the main threats to seagrasses in the Gulf and recommendations for their conservation and management.