BIOASSESSMENT OF COASTAL WATER QUALITY IN PENYENGAT ISLAND BASED ON MACROZOOBENTHIC COMMUNITY STRUCTURE

Abstract

The coastal ecosystem of Penyengat Island in Tanjungpinang City is an area with high ecological and economic value, however, various anthropogenic activities such as settlements, sea transportation, tourism, and reclamation around the Tanjungpinang coast are suspected to put pressure on water quality. This study aims to determine the abundance and ecological index of macrozoobenthos, water quality conditions based on the A Marine Biotic Index (AMBI), and the relationship between macrozoobenthos abundance and water physicochemical parameters. The study was conducted in February 2026 using a survey method with a systematic random sampling technique. Sampling used an Ekman grab measuring 30 × 30 cm. Data were analyzed using diversity, evenness, dominance, AMBI index, and Spearman correlation tests. The results showed that 24 genera of macrozoobenthos were found consisting of the classes Gastropoda (12 genera), Bivalvia (8 genera), Malacostraca (1 genus), Polychaeta (2 genera), and Oligochaeta (1 genus) with an abundance of 42.22 ind/m². The diversity index (H') value is classified as moderate (2.67), uniformity (E) is high (0.84), and dominance (C) is low (0.10). In general, the water quality still meets the quality standards. Based on the AMBI value, the quality of the coastal waters of Penyengat Island is classified as slightly polluted, which indicates environmental pressure due to the input of organic materials. The results of the Spearman correlation test indicate that the physicochemical parameters have a very weak and insignificant relationship.