Trophic Structure Analysis Of Reef-associated Fishes

Due to overfishing,habitat destruction,environmental pollution and other reasons,the fishery resources of Yellow Sea and Bohai Sea are in serious decline.In order to protect marine resources and develop fishery economy,marine ranching has widely carried out in Shandong coastal areas,and artificial reefs were put into use in order to restore the degraded habitat and protect fishery resources.Taking the artificial reef habitat near Shuangdao Bay as an example,we analyzed the trophic structure of reef-associated fishes in the artificial reef habitat using stable isotope technology and stomach contents analysis technology,including feeding habit,trophic level and trophic niche,etc.,to explore the trophic structure of reef-associated fishes in the artificial reef habitat,in order to provide supplementary data for the study of composition and food web of reef-associated fishes,and further provide theoretical basis and guidance suggestions for the construction and sustainable development of artificial reef.The main conclusions are as follows:(1)The trophic level of fish in the artificial reef habitat in Shuangdao Bay ranged from 3.68 to 4.25,which belongs to the medium and high trophic level.In addition,the high trophic fish Hexagrammos otakii(TL>4.00)was caught all year round,indicated that the artificial reef habitat was less affected by overfishing.(2)In spring,the reef-associated fish in artificial reef habitat in Shuangdao Bay had the lowest niche utilization and the highest trophic redundancy,at this time,the community stability was the highest and the ability to resist external disturbance was the strongest.In summer and autumn,the prey resources for fish to feed on decreased,and the fish community adopted to expand the feeding range to ensure the survival.(3)Sebastes schlegelii and S.hubbsi were similar in feeding habits.The main food sources were Teleost,Decapoda and a small part of Amphipods.In four seasons,S.schlegelii tend to feed on higher trophic levels than S.hubbsi.(4)In this study,the trophic niche width of S.schlegelii was higher than that of S.hubbsi in four seasons,which means that S.schlegelii had stronger utilization and competitive ability of food resources.In autumn,the niche overlap of S.schlegelii and S.hubbsi was the highest,which was consistent with the dietary overlap index of the two species.