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The biogeography of pelagic tunicates belonging to the two taxonomic classes Larvacea and Thaliacea was analysed using seven sampling stations along the coastal regions of Taiwan which contribute to all the China Seas surrounding Taiwan. The collected data were then compared with the information in the available literature about pelagic tunicate species diversity in the China Seas (Bohai Sea, North Yellow Sea, East China Sea and South China Sea) and previous studies on these organisms in Taiwan waters to get a better understanding of their biodiversity, abundance and distribution. A total of 19 species of pelagic tunicates were observed and identified to the speciel level: five species belonging to the class Larvacea, in the two families Oikopleuriidae and Fritillariidae; 14 species belonging to the class Thaliacea, in the families Salpidae and Doliolidae. We summarised morphological characteristics of the recorded species which were found to be useful for identification, and we provided further information about their global distribution and ecological preferences. Our results revealed that pelagic tunicates occurred in the China Seas with high species richness throughout the year. This is the first account on the class Larvacea from Taiwan. Comparing our results with available records from all China Seas, Taiwan proved to be a species diversity hotspot for pelagic tunicates, especially for the family Salpidae. The waters of southern Taiwan showed a higher species richness compared to the northern counterpart. The doliolidDoliolum denticulatumcan be designated as an indicator of the low-temperature China Coastal Current species. [ABSTRACT FROM AUTHOR]

The western North Pacific north of Taiwan is an area with high oceanographic complexity, both biological and physicochemical. The northward flowing Kuroshio Current passes here and turns northeastward at the break of the East China Sea continental shelf, inducing an upwelling. We used a NorPac plankton net with opening-closing mechanism to take plankton samples at six depth levels (0, 50, 100, 150, 200, and 250 m) in four time series (00:00, 08:00, 15:00, and 21:00 local time) within 24 hours. Planktonic copepods were identified to species level when possible; depth and time of collecting, and abundance in individuals/m3 were recorded. Different patterns of diel vertical migration (DVM) were established for the dominant species, such as normal DVM in Paracalanus aculeatus, Clausocalanus furcatus, Temora discaudata, and Canthocalanus pauper, reverse DVM in Oithona atlantica, no apparent DVM in Oncaea venusta and Subeucalanus mucronatus, and bimodal vertical distribution in Clausocalanus mastigophorus and Cosmocalanus darwini. Four sampling groups and four copepod species assemblages were defined by using cluster analysis. Each of these sampling groups and species assemblages is characterized by a different DVM pattern. [ABSTRACT FROM AUTHOR]