Structural redundancy of fish assemblage in Haizhou Bay and its adjacent waters

Human activities including overfishing, environmental pollution and climate change affect the dynamics and stability of marine fish communities. In order to deeply explore the community structure and its change of fish assemblage, multivariate statistical analysis and structural redundancy analysis were used to examine the spatial structure and structural redundancy of fish community based on the data from the bottom trawl surveys in spring and autumn in 2011, 2013-2016 in the Haizhou Bay and its adjacent waters. The results showed that the fish assemblage could be divided into two fish communities, i.e. the northern community and the southern community in spring and autumn in the waters. Typifying species were composed of Enedrias fangi, Liparis tanakae, Lophius litulon and Hexagrammos otakii for the northern community and Larimichthys polyactis, Cynoglossus joyneri, E. fangi and Conger myriaster for the southern community in spring. Typifying species included Chelidonichthys spinosus, Saurida elongate and C. myriaster for the northern communities, and comprised C. joyneri, Collichthys lucidus, Miichthys miiuy, Chaeturichthys stigmatias, L. polyactis and Johnius belangerii in the southern community in autumn. There was one response unit for the fish assemblages in spring and autumn, and the structural redundancy of fish community was low. The composite species in the response unit was similar to the typifying species in the northern and southern fish communities, indicating that the spatial patterns of fish community in spring and autumn in the Haizhou Bay were determined by a few species. The number of substitute species was few, and the stability of fish community was low in the Haizhou Bay and its adjacent waters.