Abstract:From May 21 to 23 and on May 27, 2014, during light falling net fishing operations in the central Nansha Islands waters, the samples of meso-and micro-zooplankton were collected and analyzed to investigate their changes before and after the light trap. The results showed that zooplankton were sensitive to artificial light at night; the community of zooplankton was affected by artificial nighttime light. A total of 178 zooplankton species belonging to 16 groups were recorded before and after the traps. The results show that the number of species increased after traps. The succession rate of species compositions was estimated at 41%, except Cladocera, all the 15 groups of zooplankton showed significant changes in species composition. Except for the Protozoa which showed a decline in species number, all groups showed a tendency of increased species number after traps. The results also indicated that most of the zooplankton species are sensitive to light traps, either positive or negative, and the occurring frequency of dominant species decreased obviously after light traps. The dominant species composition was changed after light traps (replacement rate was 50%). Before light traps, the Copepoda was the main dominant species. The dominant degree of Appendiculata was dramatically enhanced after light traps. The dominant species of meso-and micro-zooplankton in Nansha Islands trended towards cumulative distribution. All dominant species were sensitive to artificial light. The adaptation to light was different between species. Most dominant species had high adaptation to light; their aggregation intensity was enhanced after light traps, such as Oikopleuridae. The aggregation intensity of Farranula gibbula and Corycaeus agilis was reduced after light traps. At first, the aggregation intensity of Copepoda larvae and Acartia negligens was enhanced, but then the intensity was significantly reduced. Biomass and density of zooplankton were significantly increased in the overall trend, with the largest increase occurring during the initial trap, then declined, but still remaining higher than before the trap. As increase in nekton feeding intensity led to the fall of zooplankton. Although the species richness and diversity were significantly improved by the light trap, the structure of the zooplankton community did not change. Zooplankton species react to artificial light, and the difference between groups is determined by the biological and physiological characteristics of different feeding strategies. Artificial light pollution is a global environmental issue, the ecological impacts of which are only now beginning to be examined in detail. Current knowledge of these impacts in marine ecosystems is insufficient. Although the light trap increases production, but it is important to pay attention to and strengthen the ecological effects of science, and strictly limit the intensity of light trapping with appropriate restrictions on the development of light trap fisheries.