GD0057 SOUTH CHINA SEA GEOLOGICAL SURVEY WORK CARRY OUT BY M/V “HAI YANG SHI YOU 707” “HAI YANG SHI YOU 708” “HAI YANG SHI YOU 709” “HAI YANG SHI YOU 623” “NAN HAI 503” IN AREA BOUNDED BY 20-28-37.7N 113-09-54.7E，20-37-43.3N 113-26-54.5E，20-44-11.4N 113-27-02.6E，20-44-07.5N 113-30-29.7E，20-37-31.2N 113-30-21.3E，20-33-17.4N 113-53-32.2E，20-28-09.9N 113-52-28.6E，20-32-11.2N 113-30-27.4E AND 20-23-00.7N 113-13-18.1E FROM 1 APR. TO 31 AUG. SIGNAL LIGHTS AND SHAPES WILL BE EXHIBITED ADVISED TO AVOID GUANGDONG MSA CHINA