胶州湾近岸浅水区鱼类群落结构及多样性

Abstract

Jiaozhou Bay,which locates in the south of Shandong Peninsula,is a semi-closed natural bay extending from the Yellow Sea.It serves as an excellent spawning and feeding ground for fishes and other invertebrate animals,and is an important ecosystem with high productivity and biodiversity.However,due to the high fishing pressure,pollution,coastal development and the effect of global warming,major changes have taken place in the region.Based on the data collected monthly in the set net survey from March 2009 to February 2010 in Jiaozhou Bay,fish community structure and species diversity were examined by ecological diversity indices and multivariate statistical analysis.The results showed that there were 44 species of fishes(young of the year) in the survey,of which 27 species were marine fish,and the rest 17 species were estuarine fish.The fish species composition of Jiaozhou Bay was closely related with the bottom water temperature and salinity.The Margalef species richness index(R) of fish species composition in Jiaozhou Bay ranged between 0.33 and 3.50,and the Shannon-Wiener diversity index(H′) were from 0.42 to 2.25,with the Pielou evenness index(J′) varying from 0.23 to 0.93.According to the hierarchical cluster analysis(CLUSTER) and non-metric multi-dimensional scaling(MDS) analysis,fish samples were classified into three month-groups,which are group 1(G1,December—April) with the lowest bottom water temperature,Group 2(G2,May—June,October—November) with higher water temperature and Group 3(G3 July—September) with the highest water temperature.The typifying species in G1 were some resident cold temperate fish species such as great pipefish Syngnathus acus,blenny Enedrias fangi,sand eel Ammodytes personatus;Japanese anchovy Engraulis japonicus and great pipefish Syngnathus acus were main typifying species in G2,Pacific chub mackerel Scomber japonicus,cardinal fish Apogonichthys lineatus,Amoya pflaumi and other migrate fish species were typifying species in G3.The analysis of similarities(ANOSIM) indicated that there were significant differences in species compositions among the three month-groups.The biota-environment matching(BIOENV) analysis showed that bottom water temperature was the main environmental factor that determined the temporal pattern of fish assemblage in Jiaozhou Bay.About 40 larval and juvenile fish species were found in Jiaozhou Bay,but they are mainly low-valued fish species.The results indicated that the capacity as a spawning and nursery ground has declined in Jiaozhou Bay.Some measures should be taken to conserve and restore the ecological environment and fishery resources in the region.