| The fish community distribution of Kunshan with relation to physiochemical parameters was studied by seasonally samples collected from July to November 2018.Samples were collected from 23 sites which were situated in the water of Kunshan.The aim of the study was to identify the number of species and their diversity in Kunshan in relation to different kinds and intensity of human activities carried out in the area.The approach of fish survey and sampling were conducted through market analysis by the deployment of gillnet and cages.The water from lakes and rivers is used for many purposes in Kunshan including irrigation,fishery,industrial uses,tourism activities and so on.The fish collection was done with gillnet of different mesh sizes and cages of different measurement.49 species were identified during the study belongs to 12 orders and 18 families.Besides identification relatives,occurrence and index of relative important species of fishes were discussed.Occurrence or appearance of species in the 23 sampling sites during the present survey showed that most of the species were recorded in Y16 site with a total number of 22 species followed by Y17,Y14 with 21 species respectively and Y9 with 19 species.Y4 site has the least number of species recorded with only 5 species.Following index of relative importance(IRI)Coilia nasus appeared the leading and dominant species of the community(17.91%)followed by Pseudobrama simoni(10.37%)the only two dominance species.Meanwhile,there were more essential species that appeared in the catches.There were less common species compared to essential species.There were more rare species in comparison to essential and common species with the percentage as shown,being led by the least rare species respectively as follows Xenocypris argentea Gunther(0.03%),Hyporhamphus intermedius(0.03%),Odontobutis obacurus(0.03%)and Rhodeus ocellatus(0.03%).Though there were many rare species that may depend on the limited time for the assessmentFish Biological information shows that the total length of fish ranged between 22.03mm to 190mm,with an average length of 111.66mm;the body length range is 14.18mm to 1 85mm,the average body length was 93.79mm;the weight range was 0.05g to 1386g and the average weight was 21.81g.Statistics show that the length of 62.57%of the fish are more than 170mm,most of them concentrated between the 20mm to 170mm,only 1.72%of the total length of the fish is more than 270mm,64.36%of the fish body length is below 160mm,of which the body length in 60mm to 110mm accounted for 25.25%of the total,Only 1.25%of fish with fish body weight greater than 220mm;66.97%are between 0.05g-25g,and fish weighing more than 250g are only 52 tails,accounting for 0.76%of the total.Most are carp,bighead carp and Culter class.Individuals are increasingly distributed from small to large,and fish individuals tend to be miniaturized.The length-weight relationship was varied in a population because of feeding,reproduction and fishing intensity on the community.Fish diversity was assessed by calculating the various diversity indices such Shannon-Weiner diversity index(H’),Pielou’s evenness index,Margalef’s richness index.Shannon-Weiner index was 2.881 and 2.717 during summer and autumn consecutively,Pielou’s evenness index was 0.757 during summer and 0.742 during autumn meanwhile,and Margalef s richness index was 5.716 during summer and 5.121 during autumn.All the indices varied from the two seasons and from the twenty-three sampling sites,during summer Shannon-Weiner index in the 23 sampling sites from Y1 to Y23 ranged from 0.163 to 2.24,Pielou’s evenness index ranged from 0.235 to 0.962 and margalef’s richness index ranged between 0.267 to 3.052.meanwhile diversity indices in the 20 sampling sites excluding Y1,Y12 and Y13 which were not included in the seconding sampling during autumn shows Shannon-Weiner index ranged between 0.883 to 1.98,Pielou’s evenness index ranged between 0.533 to 0.952 and Margalef’s richness index ranged between 0.07 to 2.82.Species diversity was found to be high during summer that might be coinciding with conditions such as sufficient temperature and availability of food resources.The diversity and fish distribution were low in autumn probably due to a decrease in water temperature.The low valve of dissolved oxygen coupled with low biochemical Oxygen demand(BOD).The factors were responsible for declining population of fish species in Kunshan was discussed in details and to save this diversity and develop sustainable fishery practices and proper documentation leading to diversity information system is an urgent need.The mean values of water physicochemical parameters in selected sites along the Kunshan Rivers and Lakes was varied and ranges as the following,pH ranged from 6.98 to 7.85 with average valve 7.55,DO ranged from 1.83 to 8.01mg/L with average valve 5.3mg/L,Turbidity(NTU)ranged from 6.57 to 107 NTU with average valve 42.49NTU,Depth(H)ranged from L.to 3.4m with average valve of 2.08m,Transparency(SD)ranged from 8 to 45cm with average valve 21.28cm and Temperature(T)ranged from 15.6 to 19.7℃ with average valve 16.8℃ as the present work includes the detailed structure of physicochemical parameters depicting water quality status of Kunshan sampling sites as different physicochemical aspects play a crucial role in ecology of aquatic ecosystems.The values of various parameters vary at different stations in Kunshan.Therefore,the main threat of fish resource in Kunshan,aquatic biological resources are facing major threats to alien species,invasive alien species e.g.Merry Gala(Mrigal carp).Large fishing intensity,large catching severe water pollution,and the serious water pollution is located in the Liuhe Loujiang River section of Kunshan City.Recommendations for the protection and restoration of aquatic biological resources protect and recover suggest on fish resources.Artificial proliferation release enhancement and releasing establishment of aquatic germplasm resource banks and proliferative discharge centres in Kunshan waters,including fish class,shrimp,crab,shellfish and so on.Increase the supervision and monitoring of aquatic organisms that enhance,supervise and monitor.That will strengthen its propagation,its governance,its monitor,and its roundly implementation.Increase the intensity of ecological water transfer to increase environment quality(Waters transfer).Understanding the biodiversity indices provide key information for conservation and management of natural aquatic ecosystem,the study played a great role because indiscriminate-killing of brood and juvenile fishes of local and commercial species and over-extraction of this fishes during breeding season greatly decreasing the fish diversity of the study area. |
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