Seasonal variation in species composition and abundance of demersal fish and invertebrates in a Seagrass Natural Reserve on the eastern coast of the Shandong Peninsula, China

摘要

Seagrass habitats are structurally complex ecosystems,which support high productivity and biodiversity.In temperate systems the density of seagrass may change seasonally,and this may influence the associated fish and invertebrate community.Little is known about the role of seagrass beds as possible nursery areas for fish and invertebrates in China.To study the functioning of a seagrass habitat in northern China,demersal fish and invertebrates were collected monthly using traps,from February 2009 to January 2010.The density,leaf length and biomass of the dominant seagrass Zostera marina and water temperature were also measured.The study was conducted in a Seagrass Natural Reserve (SNR) on the eastem coast of the Shandong Peninsula,China.A total of 22 fish species and five invertebrate species were recorded over the year.The dominant fish species were Synechogobius ommaturus,Sebastes schlegelii,Pholisfangi,Pagrus major and Hexagrammos otakii and these species accounted for 87％ of the total number of fish.The dominant invertebrate species were Charybdis japonica and Octopus variabilis and these accounted for 98％ of the total abundance of invertebrates.There was high temporal variation in species composition and abundance.The peak number of fish species occurred in August-October 2009,while the number of individual fish and biomass was highest during November 2009.Invertebrate numbers and biomass was highest in March,April,July and September 2009.Temporal changes in species abundance of fishes and invertebrates corresponded with changes in the shoot density and leaf length of the seagrass,Zostera marina.