Secretariat, Southeast Asian Fisheries Development Center
Abstract
A collaborative cruise in the South China Sea in the waters of the South China Sea off the Western Philippines was conducted in the post-monsoon (April and May, 1998) periods on board MV SEAFDEC. The nanoplankton (including the smaller microplanktonic species) from 31 sampling stations consisted of more than 200 taxa comprising predominantly of nanodiatom (>150 species), Prymnesiophyta (>48 species), Dinoflagellata (>30 species) and Prasinophyta (>18 species). Among the minute plankton collected, three species of nanodiatom (Minidiscus comicus, M. chilensis, M. trioculatus) and numerous Prymnesiophyta species were present. The dominant pennate diatom comprised of Synedra parasitica, Fragilaria brevistriate, Diploneis crabro and Neodenticula sp., all of which were 5 L-1 - 5 x 105 L-1) especially in the nearshore waters. The total nanoplankton population (ranging from 3.1 x 105 to 2.47 x 105 L-1) was dense in nearshore regions (especially around Subic and Manila bays) and tend to spread out in concentric semicircle into the open sea. The presence of the dinoflagellate species of Protoperidinium and Alexandrium were detected in considerable amounts at nearshore and midshore Philippines waters of the South China Sea. Blooms of Pyrodinim bahamense and Protoperidinium sp. (to a limited extend) occurred during the study period
