Assessment of seagrass communities along the Jordanian coast of the Gulf of Aqaba, Red Sea

The distribution and abundance of seagrass communities have been investigated from from three sites along the Jordanian coast of the Gulf of Aqaba. The results showed that the seagrass Halophila stipulacea has the widest distribution in all sites. However, the species Halodule uninervis and Halophila ovalis were less abundant and were found at the Tala Bay site and only at shallow depths. The seagrass distributions increased with increasing depth up to 12 m, and thereafter declined. However, in some shallow areas, seagrass is completely absent due to extensive human activities. On average, the highest seagrass cover from this study was recorded at the Tala Bay site (36.6%), followed by 29.9% and 22.9% at Phosphate Loading Berth and Hotel Area sites, respectively. The mean biomass of leaves for the seagrass species H. stipulacea averaged 104.2 g m-2. The values increase with depth, reaching maximum at 12 m depth and followed by decrease down. Changes in mean leaf density, length, width, number of shoots and shoot length in all sites closely followed changed in biomass. These could be attributed to decreasing irradiance and as an adaptive change response to lower light intensities and lower growth rates at deeper depths.