Biomass estimation by hydro-acoustic methods in the South China Sea, Area II: Sarawak, Sabah and Brunei Darussalam

The abundance of fisheries resources and their structure off shore of Sarawak, Sabah and Brunei Darussalam were investigated under the SEAFDEC Collaborative Research Survey. Hydro-acoustic surveying by using a scientific echo sounder model FQ-70 was conducted for estimating the fish abundance and biomass. Two survey cruises were carried out by M.V. SEAFDEC during 10 July to 2 August 1996 and 1 to 24 May 1997 for pre and post-northeast monsoon seasons, respectively. The scientific echo-sounder was equipped with an echo-integrator and two quasi-ideal beam transducers with operating frequencies of 50 and 200 kHz. For pre and post-northeast monsoon season was 1,717,852 tons and 956,397 tons, respectively. The maximum fish abundance were found at the water depth between 100 to 200 m was 92.4% and 49.8% of total abundance for pre and post-northeast monsoon season, respectively.