P025

Combined Underwater Acoustic and Radar Instruments for Assessing Fish

Near Seabed and Mapping Seabed

A0067 Henry Manik Marine Instrumentation Engineering Laboratory, Tokyo University of Fisheries

A0068 Masahiko Furusawa Marine Instrumentation Engineering Laboratory, Tokyo University of Fisheries

Underwater acoustic and marine radar survey was conducted for

assessment of fish near seabed and for seabed mapping. For the

purpose, a high resolution underwater acoustic instrument (split beam

echo sounder), a ground penetrating radar, an oceanographic

measurement instrument were used around Seribu Island, Jakarta Bay.

Research vessel Mina Jaya (30 GT) and various marine research

instruments were employed during the survey. The result of this

research consists of distribution of fish target strength,

oceanographical condition distribution, bathymetric map, sea bottom

map and shallow subbottom profile.Fish near seabed has a target

strength value from ? 50 dB to ? 35 dB. Radar has a high resolution

for subbottom detection than acoustic method.