Characterizing the nektonic invertebrate communities in the Yangtze River estuary and its adjacent waters

Abstract

Although fisheries for invertebrates are increasing rapidly worldwide, many of them lack the rigid assessments and regulations that are typical of finfish fisheries. We report nektonic invertebrate communities of the Yangtze River estuary in the boreal autumn (November) from 2013 to 2017, and report how these are related to environmental variables. Communities comprise 26 macro-invertebrate nektonic species in 11 families, of which 8 species are dominant in abundance and biomass. Significant temporal variation in abundance, biomass, and diversity is apparent. Highest Margalef richness (D), Shannon–Wiener diversity (H’), and Pielou’s evenness (J’) index values occur in 2015, and the lowest occur in 2017. Abundance and biomass peak in 2013 and decline to their lowest values in 2017. Redundancy analysis and analysis of similarities identify significant spatial and temporal variation in nektonic invertebrate communities to have occurred from 2013 to 2017, attributable to variations in dissolved oxygen, temperature, salinity, total suspended matter, and pH. Significantly different communities occur in the northern and southern waters. Depth, total suspended matter, dissolved oxygen, pH, and total phosphorus significantly affect the distributions of dominant species. An improved understanding of spatial and temporal variation in nektonic invertebrate communities of the Yangtze River estuary facilitates their conservation and resource management.