Ecological Characteristics Of Zooplankton In The Northern Jiangsu Shoal In Spring And Summer

Food zooplankton as well as fish larvae and juveniles were investigated in spring and summer in Xiangshui, Rudong and Qidong, north Jiangsu shoal.First, spatial variations in biomass and abundance of the species and population components of zooplankton, along with ecological characteristics of dominant species and community diversity were investigated in spring and summer at the zones above.A total of 59 species (excluding planktonic larvae) of zooplankton belonging to 4 phylum, 10 class were collected in the investigation, including Copepoda, Mysidacea, Cumacea, Amphipoda, Euphausiacea, Decapoda, Chaetognatha, Tunicata, Pteropoda and Heteropoda.The total species collected in spring were 43, with 31 species in Qidong, 17 in Rudong and 15 in Xiangshui, respectively. Among different community compositions, Copepoda was predominant at all three hydrological zones. Copepoda, Mysidacea, Chaetognatha and Pteropoda occurred throughout the three zones, along with Euphausiacea and Amphipoda in Rudong and Qidong, Tunicata and Cumacea in Xiangshui, Decapoda and Heteropoda in Qidong, respectively. Zooplankton biomass and abundance in three hydrological zones were Qingdong>Xiangshui>Rudong, which were 845.54 mg/m3, 378.41 mg/m3 and 26.70 mg/m3, 226.68 ind./m3, 145.09 ind./m3 and 90.89 ind./m3, respectively. The main dominant species in the investigation were Labidocera euchaeta, Calanus sinicus, Acanthomysis longirostris, Schmackeria poplesia, Acartia bifilosa, Sagitta crassa, Paracalanus parvus, Acartia pacifica and Peraclis reticulate,etc. Among which, Labidocera euchaeta and Calanus sinicus prevailed throughout all three zones, particularly Labidocera euchaeta. The diversity index (H') at three zones were Qidong (2.59)>Xiangshui (2.28)>Rudong (2.26).The total species collected in summer were 34, with 21 species in Xiangshui, 18 in Rudong and 15 in Qidong, respectively. Copepoda, Mysidacea, Chaetognatha Euphausiacea and Decapoda occurred throughout the three zones, along with Cumacea and Amphipoda in Rudong and Qidong, Tunicata in Xiangshui, respectively. Copepoda was predominant in summer at all three hydrological zones which occurred in spring as well.Zooplankton biomass and abundance in three hydrological zones were Qingdong> Rudong>Xiangshui, which were 537.27 mg/m3, 294.79 mg/m3 and 108.35 mg/m3, 186.31 ind./m3, 182.88 ind./m3 and 77.57 ind./m3, respectively. The main dominant species in the investigation were Labidocera euchaeta, Sagitta crassa, Centropages dorsispinatu, Sagitta bedoti and Pseudeuphausia sinica, etc. Among which, Labidocera euchaeta and Centropages dorsispinatus prevailed throughout all three zones, particularly Labidocera euchaeta. The diversity index (H') at three hydrological zones were Qidong (2.21)> Rudong (2.12)> Xiangshui (2.10), which revealed that the community diversity of zooplankton in north Jiangsu shoal was increasing from north to south.Second, fish larvae and juveniles were investigated in Xiangshui and Rudong, north Jiangsu shoals. It's indicated that the distributions of fish larvae and juveniles were closely related to the abundance of zooplankton, which was the higher the latter one, the more the former one. Hydrologic zone with luxuriant zooplankton highlights its strong feeding role for fish larvae and juveniles.