Identification and classification of coral lifeform using hydroacoustic method

Abstract

Information on bottom types includes coral reef, sediment characteristics and underwater vegetation in shallow water is very important for many application, however, this information are not easy to obtain. In this study, acoustic techniques were used to identify and classify coral lifeform and others bottom types. Data collection was carried out in Seribu Islands, Jakarta using SIMRAD EY 60 scientific echosounder systems with operating at frequency 120 kHz. Volume backscattering strength values obtained from the first and second acoustic bottom return. Clustering method were used to classify coral lifeform based on both value the first acoustic bottom return (E1) and the second acoustic bottom return (E2). Data validation of the coral lifeform was performed using visual observation, which was recorded using underwater camera. The results show that average value of volume backscattering strength (Sv) from E1 varied from -18,10 dB up to -10,09 dB, while from E2 varied between -49,42 dB up to -31,81 dB. The average value of surface backscattering strength (SS) range from -20,16 dB until -28,17 dB. The results of clusterring analysis showed coral lifeform and others bottom types can be clustered into two groups: group A (CM and CMR) and group B (ACT and CS, ACB and CF, Rubble and sand) respectively.

Terumbu karang merupakan salah satu ekosistem pesisir yang berperan penting dalam kelangsungan hidup biota perairan yaitu sebagai habitat bagi makhluk hidup yang kehidupannya berasosiasi dengan lingkungan perairan. Perairan Indonesia terkenal memiliki keanekaragaman jenis karang tertinggi di dunia, disamping Filipina dan Australia. Mengingat wilayah perairan Indonesia yang sangat luas dan pentingnya habitat terumbu karang sebagai suatu ekosistem, sehingga kajian terhadap keberadaan terumbu karang di Indonesia masih terus dilakukan.