Condition and Biodiversity of Hard Coral at Gangga Island, North Sulawesi

Gangga Island (North Minahasa District, North Sulawesi Province) is located at 1º 46 19N - 125º 03 11 E. Coral reef ecosystem dominated of its coastal areas. Increasing human activities in the area is thought to influence the condition of coral reef and its diversity. This study aims to observe the condition and biodiversity of hard coral in the Gangga Island waters. This study was conducted in May 2011 at 5 (five) stations, i.e. Station 1 (Lihaga Island), Station 2 (Gangga 1), Station 3 (Tindila Island), Station 4 (Panjang Beach) and Station 5 (Gangga 2). The Line Intercept Transect (LIT) method was applied in this study. There were 106 species of hard corals consisting of 16 families found in location. The condition of hard corals was classified into middle to good, and the persentage of coverage was in between 24.24 - 73.30 %. Corals at station 1 were in the good location and they have the highest diversity index (1.17), while the highest evenness index was at Station 3 (0.91). Generally, at Gangga Island, the domination of hard coral was 10.958 cm or 43,83 % (depth 3m) and 12.116 cm or 48,46 % (depth 6m) of the total transect (25,000 cm) with coral species of Acropora sp (2.344 cm) or 9,38 % at depth of 3m and Porites nigrecens (3.751 cm) or 15 % was dominant at depth of 6m. Result of this study can be used in management coral reef ecosystem policy of the goverment of North Sulawesi.