Abstract
Sea grasses are well known for their ecological importance providing shelter and nurseries for various aquatic animal species, protect coral reefs from turbid waters, support biodiversity, and trapping nutrients received from terrestrial ecosystems. Sea grasses represent the major components of marine ecosystems and are strong indicators for the ecological health of coastal marine ecosystems. By assessing the eco-physiology of sea grasses, impacts of activities developed in that coastal area can be assessed and monitored. In this quantitative assessment of sea grass diversity, frequency, density, abundance, and dominance were determined on the selected coastal sites of the Red Sea at Haql in October 2020. Five common sea grass species namely Cymodocea rotundata, Halodule pinifolia, Thalassodendron ciliatum, Halophila stipulacea, and Thalassia hemprichii were selected for this study. Quadrats of 1m(2) were used for data collection. There was a marked difference in quantitative parameters of sea grass diversity. From the following research, it can be concluded that the sea grass diversity showed spatial variations within and between the selected coastal study sites. The results provide preliminary data which can be utilized to compare the diversity of observed sea grass species.