Species Composition And Spatio-temporal Distribution Of Dominant Species Of Zooplankton In Jiaozhou Bay

Zooplankton, as a connecting link between phytoplankton and fish, plays a vital role in the marine ecosystem. Jiaozhou Bay was a typical area severely affected by natural variation and human activities. The species composition and spatio-temporal distribution of zooplankton are critical to understand the actuality and future status of the bay ecosystem, and to predict the responses of plankton to climate changes and human activities.The zooplankton community in Jiaozhou Bay was studied based on the samples collected by vertically towing a 50 cm diameter net (mesh size 500 μm) and a 31.6 cm diameter net (mesh size 160 μm) monthly in 2004. Species composition and spatio-temporal distribution of dominant species were determined. Seventy-four species were identified, belong to 2 ecotypes: warm-temperate neritic species and warm-temperate margin sea species. The total abundance of zooplankton ranged from 1006-15571 ind./m~3 with an average of 5187 ind./m~3. While classified into 4 groups by body length, 3mm respectively, the small zooplankton (<1mm) was most abundant. The seasonal variation of species richness, zooplankton density and biodiversity were similar, higher in spring and summer, lower in autumn and winter. Zooplankton was more abundant in the inner of the bay and less in the outer. The horizontal distribution of biodiversity (Shannon-Weaver Index) was inverse with that of abundance, higher in the outer part and lower in the inner part.Acartia bifilosa, Calanus sinicus, Paracalanus parvus, A. pacifica, Corycaeus qffinis, Oithona similis, Oikopleura dioica, Sagitta crassa, O. brevicornis, Rathkea octopunctata, Podocoryne minima were dominant species. Seasonal variation of dominant species was evident. A. bifilosa and C. sinicus, as dominant species in spring, reached abundance of up to 5604 ind./m~3, 493 ind./m~3 respectively in April. O. dioica occurred abundantly in June with a...