This research was conducted in April-May 2019 in the waters of Poncan Island, North Sumatra Province, which aims to determine the large nutrient content of substrate (nitrate and phosphate), the level of seagrass density Enhalus acoroides, and to determine the effect of nutrient content of the substrate on the density of seagrass Enhalus acoroides. Determination of the research station by purpo…