Abstract

This research was conducted in coastal waters of Tongkeina, Bunaken Sub-district, Manado City, North Sulawesi. The purpose of this research is to know the density and morphometric characters of seagrass, Enhalus acoroides on different substrates in Tongkeina waters. Data collection was conducted by using quadrant transect method. At the location of the study, three data retrieval points consist of muddy substrate, muddy sand substrate, and rubble were established. To collect data, 6 quadrant transects were lied down parallel to the coastline along the seagrass bed with a total distance of 50 m while the distance of 10 m between quadrant were applied. At each sampling point a 50 cm x 50 cm quadrant transect is placed systematically on 6 points in the each sub-station. Density observation was done by counting the number of seagrass stands on the transect at each observation point at each station. Pictures were taken with a waterproof camera and were classified accordingly based on the size of the squares. The highest numbers seagrass and morphometric characters of seagrass were found on the muddy substrate. This is because the substrate relatively in quiet waters and the growth of the seagrass is more concentrated on the length and width of the leaf. While the peak of the leaf blade is often eroded by the wave energy and the openness of the study site to the tides in relatively shallow waters, it could be also caused by environmental factors such as the strong currents that obtained at these stations. This fact also contributing to cause the growth of seagrasses is centered on leaves and roots as a form to defend themselves on fine sediments. Density and morphometric of seagrass such as leaf length, leaf width, and root length on the substrate indicate significant value or show a relationship.