Distributions of environmental parameters and Plankton’s volume backscattering strength at Yos Sudarso Bay, Jayapura, Indonesia

Abstract

The present study combined the data of environmental parameters and plankton distribution using hydroacoustic technology with the purpose to map the horizontal and vertical distribution of plankton in Yos Sudarso Bay, Jayapura, Indonesia. Hydroacoustic data were processed using a threshold in the range of −90 dB to −70 dB which was used for plankton detection at a depth range of 5–100 m. The results of the current study showed that the surface temperature changed from 30 °C on the outside to 18 °C on the inside of the bay. Similarly, the salinity of the surface outside the bay was 36‰ while it was 18‰ inside the bay. The distribution of chlorophyll had also decreased, where the value outside the bay was 0.32 mg/m3 and inside the bay was 0.02 mg/m3. The horizontal distribution of the values of plankton's volume backscattering strength (Sv) had a range of −82 dB to −75 dB with an average of −76.63 dB. When the distribution of plankton's Sv was detected vertically, it showed that the value of plankton’s Sv decreased with increasing the water depth.