Study of bioindicator at mangrove island: Case study of Carey Island

This paper reviews on the bioindicator for Carey Island which is one of the mangrove islands in Malaysia. The bioindicator was used to assess the level of river pollution at Judah, Air Hitam and Keluang River rather than using normal test such as Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) tests. The bioindicators found at the sampling site were river crab, adult beetles and nymphs. By referring to the score sheet, the Biological Water Quality Index (BWQI) was calculated. As a result, the average BWQI value for all rivers indicated in range rather dirty. Meanwhile, the Chemical Water Quality Index (CWQI) shows that all the rivers were polluted in general.