A comparative study of fish community in four main estuaries of China southeastern coastal areas and their adjacent waters

Based on literature and survery data of fish composition collected by bottom trawl investigation from 2006 to 2007 in four main estuaries of China southeastern coastal areas and their adjacent waters,changes of the taxonomic diversity across spatial and temporal scales of fish community were analyzed by taxonomic diversity indices.The results are as follows:a total number of 1397 fish species(including some freshwater species),belonging to 2 classes,42 orders,186 families and 593 genera,were collected in the studied sea areas.The species richness increased with lower latitudes,particularly so with Perciformes.There were 339 fish species in the Yangtze River Estuary and adjacent waters,belonging to 2 classes,31 orders,101 families and 231 genera.There were 535 fish species in the Minjiang River Estuary and adjacent waters,belonging to 2 classes,33 orders,133 families and 323 genera.A total number of 803 fish species were collected in the Jiulongjiang River Estuary and adjacent waters,which belonged to 2 classes,35 orders,155 families and 419 genera.And 1021 fish species which belonged to 2 classes,32 orders,153 families,and 466 genera were collected in the Pearl River Estuary and adjacent waters.The numbers of orders and families of fish species from the northem to the southern waters first increased and then decreased.The average variation in taxonomic distinctness(Λ+)gradually decreased with lower latitudes in the four estuaries and adjacent waters.There were no significant differences in the average taxonomic distinctness(Δ+)among the four estuaries and adjacent waters,and fish fauna were closely related with each other,and all of them belonged to the same zoogeographical fauna(Indian-Malaysia fauna).Fish composition in the Minjiang River Estuary and adjacent waters was more similar to that in the Jiulongjiang River Estuary and adjacent waters among the four estuaries.Compared with the historical data,the average taxonomic distinctness of fish community showed a great decrease in the Minjiang River Estuary and the Jiulongjiang River Estuary and their adjacent waters.