Abstract
Aspects of the ecology, biometry and biomass of the seagrass H. stipulacea along the Jordanian coast of the Gulf of Aqaba were investigated. The vertical distribution covers a depth range of 1 to at least 50 m. There is a decrease in density and biomass with increasing depth to 45 m and an increase in leaf length with increasing depth. Vertical and habitat patterns of distribution are discussed in terms of ecological factors and inherent characters of H. stipulacea. Two populations based on differences in mean leaf length and width are recognized related to major habitats rather than depth.