Jalanidhi, R.V. 1972. Hydrological, plankton and pigment observations in the South China Sea (C.S.K. Program, Cruise II) and around Seribu Islands. Institute of Marine Research Oceanographical Cruise Report No. 6, pp. 63 Spatial Coverage: South China Sea & Seribu Islands Temporal Coverage: Dec. 6-28, 1971 Language: English Introduction & Objective: This report records the data collected during the cruise of the R.V. Jalanidhi in the South China Sea and the water around the Seribu Islands. The region of the South China Sea that has been covered by the present cruise is identical with the one covered by R.V. Samudera during her February--March cruise of 1971 (INST. MAR. RES., Oceanogr. Cruise Rep. No. 3, 1971) while the area around Seribu Islands is identical with the one covered by the R.V. Samudera during her July-- September crjuise of 1971 (INST. MAR. RES., Oceanogr. Cruise Rep. No. 5, in press). The objective of this cruise is to assess the chemical, physical and biological environment of the fishing ground sound of Natuna Islands and around Seribu Islands.