Effects of annual sediment flux from the Yellow River on the fishery resources structures in the Laizhou Bay

Based on the data by trawl surveys in August from 2009 to 2013 in the Laizhou Bay, we studied the fishery resources structures, such as species compositions, dominant species, spatial distribution and standing stock, to understand the effects of annual sediment flux from the Yellow River on the fishery resources structures in the Laizhou Bay. The result showed: (1)The relative biomass and species of fishery varied dramatically in interannual variation. Average catch of fish was more than those of crustaceans and cephalopods. And the catch of pelagic fish was significantly more than that of demersal fish, but the opposite phenomenon occurred in Aug. 2011. (2)The composition of dominant species was close to interannual variation, conducting succession from species which were high economic value and big to lower economic value and small species. The dominant species were different among 2009-2013. Main dominant species were Konosirus punctatus, Chaeturichthys stigmatias, Oratosquilla oratoria, Eupleurogrammus muticus and Loligo japonica. K. punctatus became the only dominant specie in 2010. (3)The Yellow River exports large amount of nutrients to the Laizhou Bay. The estuary of Yellow River and its adjacent area, a major fishery and spawning ground, have abundant species. The changes of sediment discharge from the Yellow River had effects on fishery resources structures and quantity of resources. The sediment discharges were significantly correlated with the number of fish species or demersal fish and the fishery resources. And the Yellow River sediment discharge was high significantly correlated with the biomass of demersal fish. In conclusion, the influence of the Yellow River sediment discharge into Laizhou Bay is an indispensable factor when we study the fishery resources and protect the larvae and juveniles.