Abstract: Based on the bottom trawl surveys in central Jiaozhou Bay from March to August 2009, and by using ecological diversity indices and canonical correspondence analysis (CCA), this paper studied the species composition of fish community, and analyzed the species diversity and its relationships with the environmental factors in the Bay in spring and summer. A total of 43 fish species were captured, belonging to 8 orders, 24 families and 38 genera. The number of fish species increased with increasing bottom water temperature. Margalef species richness index was from 2.440 to 2.770, Shannon diversity index was from 1.322 to 2.346, and Pielou evenness index was from 0.416 to 0.771. No significant differences were observed in the diversity indices between spring and summer. The ranks of the species composition and biomass in contiguous months had less change. Bottom water temperature was the most important environmental factor affecting the monthly change of fish species composition.

Key words: Jiaozhou Bay, species diversity, species composition, environmental factor, agricultural flood, indicator construction, flood index, gray correlation, southwestern China.