Seagrass Ecotourism is a tourism activities based on the ecosystem of seagrass. Component of seagrass consist of vegetation and biota that associated with the seagrass. The purpose of this research is to understand the condition biophysics of seagrass (Types of seagrass, Cover of seagrass, fish, makrozoobenthos, types of substrat, water brightness, the depth of the seagrass) and to establish the suitability of seagrass to support nautical ecotourism. This research have been done in Sibu island, Guraping village, north oba district, Tidore city for 6 month from April – September 2020. The method that used is a survey method consist of direct measuring of types seagrass, cover of seagrass, fish, makrozoobenthos, types of substrat, water brightness, the depth of the seagrass. The data analysis includes percentage of cover seagrass and the suitability index of seagrass ecotourism. The result of the biophysical study were obtained are 8 types of seagrass, cover of seagrass (51,04- 92,71%), fish (12 types), makrozoobenthos (17 types), brightness (77-100%), substart (sand, muddy sand, mud) flow speed (0,01- 0,06 m/dt) and the depth of the seagrass (1-2,5 m). Sibu island could be developed as a region of Seagrass Ecotourism with index suitability tourism (IKW) station 1,3,4 and for the whole are located in category S1 (very suitable) and station 2 is in the suitable category.

Seaweed of Caulerpa racemosa  has bright prospects for cultivation. In North Maluku province in general, the cultivation of seaweed Caulerpa sp has never been developed, even though the waters of North Maluku have enormous potential, because this type of seaweed is scattered in various marine waters in North Maluku. One of the efforts that needs to be done is to carry out this type of seaweed cultivation in an optimal and sustainable manner.The seaweed Caulerpa racemosa cultivation unit used in this study was the off-bottom method measuring 5 m x 10 m. This size can contain 5 stretch ropes/risers with a length of 10 m and a distance of 1 m between the stretch ropes/risers. Each stretch / riser line contains about 45 seed clump points with a distance between clumps of 15 cm. The observation procedure for the growth of Caulerpa racemosa seaweed was carried out by weighing the seaweed seeds in each stretch/riser rope. The weight of seed that is weighed is the weight of seeds at the time of planting and the weight of seaweed at harvest.The results showed that the average growth rate of  seaweed Caulerpa racemosa was varied for each rope. In ris 1 rope, the average absolute weight growth reached 100.88 grams, ropes 113.33 grams, ris rope 3, 88.00 grams, rope ris 4, 116.00 grams, and rope ris 5, amounting to 113, 33 grams. In general, the highest growth in absolute weight was found in the fourth rope, which was 116.00 grams.