The relation between volume backscattering strength (SV) and density of Enhalus acoroides at Wangi-Wangi Island, Wakatobi Regency

Departement of Marine Science and Technology, Faculty of Fisheries and Marine Sciences, IPB University (Bogor Agricultural University), 16680 Bogor, Indonesia

^* Corresponding author: sripu@apps.ipb.ac.id

Abstract

Seagrass is a fundamental vegetation that can optimize the function of coastal areas, to obtain information about the survival of seagrass. Thus an effective and efficient seagrass monitoring method is required. Seagrass density measurements can be performed using in-situ observation and hydroacoustic methods. The purpose of this study was to analyze the oceanographic parameters, SV values, and their correlation with the density and height of E. acoroides, as well as oceanographic parameters at Wangi-Wangi Island, Wakatobi Regency. Stationary data were acquired at five stations through acoustic clustering and in-situ diving. The density values at each station were 32 ind/m², 33 ind/m², 29 ind/m², 35 ind/m² and 37 ind/m². The range of SV values for Enhalus acoroides was (-50,19) – (-37,41) dB. The average SV values at each station were -40,76 dB, -40,63 dB, -41,10 dB, -40,48 dB, and -40,46 dB. Logarithmic regression analysis of density against SV values showed a strong relationship R = 0,96. PCA with a cumulative percentage of 92,7% from the biplot correlated most closely with the SV values of densities and seagrass heights. The project’s implications and contributions include advancing seagrass monitoring techniques using acoustic methods for improved oceanographic parameter analysis.