JOURNAL OF NATURAL RESOURCES ›› 2017, Vol. 32 ›› Issue (3): 507-516.doi: 10.11849/zrzyxb.20160318

• Resource Evaluation • Previous Articles     Next Articles

The Inter-Decadal Variations of Species Composition and Diversity of Nekton Community in Yangtze Estuary Fishing Grounds in Winter

LI Jian-sheng1, 2, JIANG Ya-zhou1, 2, JIN Yan1, 2   

  1. 1. East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China;
    2. Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation,Ministry of Agriculture, Shanghai 200090, China
  • Received:2016-03-25 Revised:2016-07-04 Online:2017-03-20 Published:2017-03-20
  • Supported by:
    National Special Research Fund for Non-Profit Sector (Agriculture), No. 201303047; Special Research Foundation for Fishery Resources Survey in Chinese Coastal Waters, No. 2014-2018.

Abstract: According to fishery survey data in the Yangtze estuary fishing grounds in three representative winters from 1991 to 2011, the inter-decadal variation of the nekton community in the area were studied. The results showed that the composition, the fishery resources density, the dominant species, the diversity and size spectrum of nekton species all changed significantly from 1991 to 2011 in the Yangtze estuary fishing grounds. The number of the nekton species overall showed an increasing trend, in which the number of fish species increased a little, but the number of crustaceans and cephalopods increased greatly. The density indices, including weights and individual quantity, all had increasing trend after a falling trend at the beginning, but the amplitudes of them were different. The average weight fell sharply at first and then kept dropping slightly. The number of dominant species was seven, nine and seven in 1991, 2001 and 2011 respectively, and the dominant species changed dramatically. The common dominant species in the three years were Ovalipes punctatus and Harpadon nehereus. The average number of nekton species at all stations showed a sustained increase, but the average richness, the diversity indices, and the evenness indices all firstly increased and then decreased. The average dissimilarity were higher than 60% between 1991 and 2011, 1991 and 2001. But the average dissimilarity between 2001 and 2011 was lower (36.05%). The number of main species which caused community difference was increasing, ecological groups have gradually expanded. The nekton size spectrum was gradually narrowed, mainly due to the species succession in the community, the increasing of small fish population and the decreasing of large fish population age structure etc.

Key words: diversity, nekton community, size spectrum, winter, Yangtze estuary

CLC Number: 

  • S932