白洋淀生态修复工程的渔业资源调控效果

针对白洋淀渔业资源衰退、生物多样性下降、水体富营养化的生态问题，设计并实施了

Effects of ecological restoration on fishery resources in the Baiyangdian Lake, Hebei Province of China

Ecological restoration has been one of the most important strategies for the ever-increasing ecosystem degradation and environmental pollution in the world. A great challenge can be also posed on the Baiyangdian Lake, the largest fresh water lake in the North China Plain, particularly for the water deterioration, biodiversity decline, and ecological function disorder. In this study, a comprehensive restoration project was implemented to restore the fishery resources in the ecosystem of Baiyangdian Lake. Some ecological restoration techniques were utilized to create habitats for the aquatic animals, aquatic plant diversity, and stock benthic organisms during the change of the bottom. A systematic evaluation was conducted to determine the regulation effect of the project on the community structure of fishery resources and the nutritional relationship between species. An investigation was also performed on the fishery resources, food web structure, and nutritional level, where the Shihoudian Lake (restoration area) was selected as the research object, and Dabaiyangdian Lake as the control. Six sampling points were set in the two areas at the same time. The results showed that the ecological restoration project increased the catch species, abundance and biomass by 35.29%, 58.60%, and 200.00%, respectively, in the restoration area, compared with the control. The fish's physical signs in the restoration area (the total length of (125.04±54.97) mm, the body length (100.22±44.44) mm, and body weight (44.02±331.45) g on average) were much higher than those in the control area (the total length 106.94±35.47mm, the body length (85.79±29.66) mm, and the body weight (19.77±82.30) g on the average). The average physical characteristics for the six types of fish (Carassius auratus, Pseudobagrus fulvidraco, Cultrichthys erythropterus, Toxabramis swinhonis, Protosalanxh yalocranius, and Rhinogobius giurinus) in the restoration area were significantly higher than those in the control area (P<0.05).The C/N stable isotope analysis showed that the mean value of δ13C and δ15N in the restoration area was higher than that of the control area, regardless of the whole catch, fish population, or invertebrate population. The one-way analysis of variance (ANOVA) of δ13C and δ15N between the two areas showed that there were significant differences (P<0.05) among the whole catch, while the fish population only had significant differences in δ15N (P<0.05) and invertebrate population only had significant differences (P<0.05) in δ13C. In addition, the δ13C span of the restoration area (6.30‰) was significantly higher than that of the control area (4.47 ‰), indicating the more abundant food organisms and the more complex food web structure in the restoration area. The trophic level analysis demonstrated that the trophic level range, the total span, and average (1.93-3.96, 2.03, and 2.99±0.66) of the main fishery organisms in the restoration area were higher than those in the control area (1.94-3.89, 1.95, and 2.76±0.70). The species with the highest trophic level in the restoration and control area were Cultrichthys erythropterus (3.96), and Silurus asotus (3.89), respectively. Meanwhile, the species number with a trophic level between 3-3.5 in the restoration area was the highest (30.43%), while the species number with a trophic level between 2.5-3 in the control area was the highest (41.18 %). Therefore, the ecological restoration project can be expected to effectively improve the biodiversity, the stable ecosystem structure, and the rapid restoration of ecological functions and fishery resources in the Baiyangdian Lake.