Preliminary Study On Fish Biodiversity And Resource Changes In Shandong Coastal Waters

Shandong coastal area is an important spawning,nursery and feeding ground for many marine organisms in the Bohai and Yellow Seas due to its superior geographical environment.With the global climate change and the intensification of human activities,the marine environment and the structure of fish resources in the Bohai and Yellow Seas have changed significantly.Based on the collection and identification of 110 species of fish samples in Shandong coastal waters,this study analyzed the changes of fish biodiversity,and combined with mitochondrial COI sequence and mitochondrial genome sequencing,analyzed the genetic diversity and phylogenetic relationship of fish species in Shandong coastal waters.By analyzing the data of temperature,salinity and depth in Shandong coastal area from 2016 to 2017,the characteristics of marine environment change in Shandong coastal area were discussed.Based on the Length-based Bayesian biomass estimator(LBB),the resource changes of eight common fish species in Shandong coastal waters were analyzed.The Catch-based maximum sustainable yield(CMSY)model and Bayesian state-space implementation of the Schaefer model(BSM)were used to evaluate the resource status of 12 common fish species in the Northwestern Pacific Ocean.The main results are as follows:(1)Compared with the 1980s,the fish biodiversity in Shandong coastal waters decreased significantly,the fish resources were mainly small species,and the fish community structure tended to be low-quality and miniaturized;(2)Based on the analysis of COI sequences of 100 species of fishes in Shandong coastal waters,and the whole mitochondrial genome sequences of Dictyosoma burgeri and Setipinna tenuifilis,the phylogenetic relationships among different species of fishes in Shandong coastal waters were constructed;(3)In 20162017,the sea surface temperature of Shandong coastal waters increased and the salinity decreased compared with the 1980s;(4)Due to the long-term overfishing,the structure of fish resources in Shandong coastal waters has changed,common economic species are facing serious overfishing pressure,and the existing resources are low;(5)the fishery resources in the Northwest Pacific have been seriously overexploited,and the resources of the population have been seriously damaged.The existing biomass of the fish such as Clidoderma asperrimum,Engraulis japonicus,Etrumeus teres,Lophius litulon,Sardinops melanostictus,Scomber australasicus,and Tanakius kitaharae is relatively low.In the face of global climate change and the pressure of international fishing industry,the following four suggestions are put forward for fishery management:(1)fishery managers should strictly regulate the fishing limit of individual size of specific species,and regulate the mesh size of nets,so as to help the reconstruction of fish stocks;(2)Fishery scientists need to collect more comprehensive and accurate biological and environmental data,so that managers can benefit from more detailed assessment of marine species status;(3)Environmental factors,especially marine stocks,are included in the evaluation of stock resources because they are very sensitive to the changes of environmental conditions;(4)Give full play to the role of the international stock assessment and management framework jointly established by China,Japan and Korea.Through the interdisciplinary study of marine chemistry,marine biology and marine ecology,this study systematically studied the characteristics of marine environment,fish biodiversity and stock resources in Shandong coastal waters,in order to provide theoretical basis and new research ideas for the regional research of offshore areas.