Analysis of structure and energy flow in southwestern Yellow Sea ecosystem based on Ecopath model

Wei Wang, Junjie Wang, Ping Zuo, Yao Li, Xinqing Zou

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Abstract

20 functional groups based on fish landing from southwestern Yellow Sea were chosen to form the basic components of the Southwestern Yellow Sea Ecosystem (SYSE) Ecopath model. Modelling results showed that the trophic level of all functional groups lies between 1.000-4.509 while the range of those functional groups, such as birds, carnivorous fishes and cephalopods having high trophic level lies between 3.417-4.509. System energy was mostly distributed in the lower part of trophic level in the food web. In 7 integrated trophic levels where the efficiency of energy transfer increased gradually from low to high levels along the food chain and the consumption and output of different trophic levels increased rapidly. The energy conversion efficient with average 13.22% was 1133%, 13.16%, 15.50%, 14.67%, 13.61% and 15.68% from level I to level Ⅶ, respectively, of which the efficient for debris took up 13.35% and for primary producer, 13.14%. Energy from primary producer took up 57% and debris shared 43% in the SYSE indicating that the grazing food chain dominated the energy flow. Mixed trophic evaluation showed that phytoplankton and debris, as producers of the system, had a positive impact on most other functional groups. The competitions among the groups had clearly negative effects, particularly among the crab, flounder, jellyfish, macrobenthos and plankton. The ratio of total primary productivity to total respiration in the SYSE was 2.541, and the Finn’s cycle index and the Finn’s cycle path length were 3.983 and 2.444, respectively. It concludes that the SYSE was still in an immature and unstable stage according to the ecosystem parameters of the model output.
Original languageUndefined/Unknown
Pages (from-to)528-539
JournalJournal of Applied Oceanography
Volume38
Issue number4
DOIs
Publication statusPublished - 10 Nov 2019

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