Functional Traits Relationships Of Fish Assemblages In Sub-lakes Of Poyang Lake Floodplain

Functional traits were defined as any biological attribute measurable on an individual that impacts organism performance and thus fitness and can be used to understand the dynamic response of community composition to external factors.Water level fluctuation is an essential factor in determining the degree of connectivity of Poyang Lake.Therefore,understanding the reaction of Poyang Lake fish communities to water level fluctuation is the key to understanding and protecting the fishery resources of Poyang Lake.In order to understand the response of Poyang Lake fish communities to water level fluctuations,our research used a method based on functional traits to describe the changes in fish communities in interannual water level fluctuations.In the study,we selected two sub-lakes of the Poyang Lake(Dahuchi lake and Bang lake)and nearby rivers(Gan river and Xiu river)as the study area.And fishes were caught in four critical periods during the water level fluctuations,which were July 2018(high water season),September 2018(Water level decline period),October 2018(dry season),and April 2019(water level rise).From the research,we came to the conclusions that:(1)Four periods collected 62 species samples belonging to 8 orders and 14 families,and the total number is 6938 samples,and the total biomass is 95936.34g.The Importance Relative Index(IRI)shows that the dominant species are Hemiculter leucisculus,Coilia brachygnathus,Tachysurus fulvidraco,Carassius auratus,and Cyprinus carpio.The Non-metric multi-dimensional analysis(NMDS)indicated that there are spatial differences in fish communities,with more significant differences between sub-lakes and rivers,seasonal differences in fish assemblages in river habitats.(2)Select 28 fish,which measured samples more than 20 to study the relationship between functional traits and ecological space.The results show that the functional traits of fish are consistent with the ecomorphology position,and the environmental function and resource utilization of fish can be predicted from the functional traits.Multiple sets of functional traits determine the ecological function of fish.The functional traits of fish with the same resource utilization may have a difference,but the main traits can be selected to predict the ecological function of fish.(3)Counted 12 species of fish with more than 100 numbers and analyzed the length-weight relationship:Acheilognathus taenianalis,Hemiculter leucisculus,Coilia brachygnathus,Tachysurus fulvidraco,Micropercops swinhonis,Carassius auratus,Cyprinus carpio,Pseudorasbora parva,Pseudobrama simoni,Squalidus argentatus,Cobitis sinensis,Rhinogobius giurinus.Micropercops swinhonis was the first record data,Acheilognathus taenianalis and Coilia brachygnathus found the new maximum and minimum full-length data,six fish found the smallest total length record,those were:Tachysurus fulvidraco,Pseudobrama simoni,Carassius auratus,Hemiculter leucisculus,Cobitis sinensis and Rhinogobius giurinus.