Study On Crustacean Resources In Xiamen Coastal Waters

Xiamen coastal waters is located at the mouth of the Jiulong River.Because of its unique geographical conditions,it is a suitable place for for many crustaceans breeding and nursery.For the area of crustacean community structure and diversity of system investigation and study is less,coupled with the passage of time,the previous studies are difficult to support the current fishery development needs.Therefore the study on the crustaceans resources of Xiamen coastal waters has an important practical significance: the survey results on crustaceans resources provide advice for the utilization of crustaceans resources in Xiamen coastal waters,and provide a reference for long-term study on the fishery resources in Xiamen coastal waters.In this survey,single bottom trawl was used for sampling in Xiamen coastal waters in 2006-2007 and 2016-2017,respectively.The crustacean composition of 7 sites on 4 voyages in 2006-2007 and 6 sites on 4 voyages in 2016-2017 in Xiamen coastal waters were investigated comprehensively,and the effects of temperature,salinity and other water environmental factors on crustaceans were discussed,which can provide basis for the utilization and protection of crustaceans resources in this coastal waters.The research results are as follows:(1)From 2006 to 2007,66 species of crustaceans belonging to 2 orders,16 families and 29 genera were captured,which including 27 species of shrimps belonging to 5 families and 11 genera,34 species of crabs belonging to 10 families and 15 genera,5 species mantis shrimps belonging to 1 family and 3 genera.From 2006 to 2007,55 species of crustaceans belonging to 2 orders,19 families and 34 genera were captured,which including 17 species of shrimps belonging to 6 families and 12 genera,32 species of crabs belonging to 12 families and 18 genera,6 species mantis shrimps belonging to 1 family and 4 genera.Diversity presents temporal and spatial differences: the diversity of autumn and winter was lower,which are higher on the east of Xiamen island.The abundance and biomass of crustaceans were higher in summer and autumn than in spring and winter.Which were lower in estuarine area.(2)From 2006 to 2007,there were 15 seasonal dominant species and 5 dominant species of annual crustaceans including Parapenaeopsis hardwickii,Metapenaeus affinis,Charybdis japonica,Portunus gracilimanus,Oratosquilla oratoria in Xiamen coastal waters.There were 17 seasonal dominant species and 7 dominant species of annual crustaceans including Parapenaeopsis acultrirostris,Metapenaeus ensis,Fenneropenaeus penicillatus,Charybdis orientalis,Charybdis japonica,Oratosquillina interrupta,Oratosquilla oratoria in Xiamen coastal waters in 2016-2017.The number of dominant species was more in summer and autumn.Compared with a decade ago,the catch of most dominant species was smaller,which were similar to dominant weight.(3)Parapenaeopsis acultrirostris,Metapenaeus ensis,Fenneropenaeus penicillatus,Charybdis orientalis,Charybdis japonica,Oratosquillina interrupta showed negative allometric growth.Compared to ten years ago,The growth rate of Parapenaeopsis hardwickii decreases in 2016-2017,which were similar to Charybdis japonica,s.The highest death rate on Charybdis orientalis,lacking of development on Oratosquillina interrupta,appropriate level of development on Parapenaeopsis acultrirostris,Metapenaeus ensis and Oratosquilla oratoria,overfished on Charybdis orientalis can be found accord to the fishery biological parameters of crustaceans.Parapenaeopsis hardwickii and Charybdis japonica were excessive development compared to ten years ago.In general,the exploitation and utilization degree of crustaceans was at a medium level in Xiamen coastal waters.(4)RDA analysis results showed that salinity,temperature,water depth and dissolved oxygen have a great influence on crustacean communities in Xiamen coastal waters.Fenneropenaeus penicillatus,Metapenaeus joyneri,Charybdis japonica,Oratosquilla oratoria were affected positively by salinity,which had negative influence on Palaemon carinicauda Holthuis,Parapenaeopsis acultrirostris,Metapenaeus ensis,Charybdis bimaculata,Charybdis orientalis,Orithyia sinica,Oratosquillina interrupta.Atypopenaeus stenodactylus,Metapenaeus affinis,Metapenaeus joyneri,Charybdis japonica,Oratosquillina interrupta were affected positively by temperature,which had negative influence on Charybdis bimaculata.Palaemon carinicauda Holthuis,Trachypenaeus curvirostris,Eucrate crenata and Portunus hastatoides were affected positively by water depth,which had negative influence on Fenneropenaeus penicillatus,Charybdis japonica and Oratosquilla oratoria.Lambrus validus and Charybdis eriatus were affected positively by dissolved oxygen,which had negative influence on Parapenaeopsis acultrirostris,Metapenaeus ensis,Charybdis orientalis and Oratosquillina interrupta.(5)crustaceous resources are decreasing because of overfishing,reclamation of sea and Marine environmental pollution in Xiamen coastal waters.strong measures to protect the crustlike resources should be taken.For example,control of fishing,strengthen the enforcement of protection measures such as the fishing period,the fishing area and the season-body fishing,ensure the effect of proliferation and discharge,strengthen the prevention and control of Marine pollution and focus on improving the quality of Marine environment.