Effect assessment of summer fishing moratorium in Daya Bay based on remote sensing data

Based on the data of satellite remote sensing and trawl surveys, we analyzed the variation in sea surface temperature (SST), chlorophyll a (Chl-a) concentration, catch per unit effort (CPUE) of total catch, biodiversity, species composition, body length and mass of total catch during the pre-SFM (May in 2015) and post-SFM (August in 2015) in Daya Bay, to assess the maintenance effect of summer fishing moratorium (SFM) in that area. Results show that the major variation range of CPUE increased from 0−10 kg·h^–1 in the pre-SFM to 0−40 kg·h^–1 in the post-SFM. The average body length and mass increased, indicating that the growth rate of total catch accelerated. In the post-SFM, the indices of Shannon-Wiener and Pielou increased by 0.36 and 0.14, respectively, which shows that the community structure was improved. The biomass spectra of the fishery resource community shows that the slopes of normalized biomass spectra in the post-SFM was over –1, and the biomass of fishery resources increased with the increase of the individual body mass in the post-SFM. SFM alleviated the fishing intensity, recovered and conserved the fishery resources in Daya Bay. In order to improve the SFM system and promote sustainable development of coastal fishery resources, it is suggested to prolong the time of SFM appropriately, reduce the number of coastal fishing boats, and enforce the conservation of fish resources.