Evaluation Of Artificial Reef Construction In Shandong Province

In recent years, affected by the increased fishing intensity and environmental pollution and other factors, fisheries worldwide are becoming more and more deteriorated. The quality and quantity of species of fishery resources reduced sharply. China,as an important fish-producing country,is particularly critical. As a means of rehabilitating the ecological environment and enhancing fisheries resource, fisheries scientists put artificial structures into the waters to help to improve the marine ecological environment and to provide attachment bases for the algae and the habitat of evading enemies, feeding, spawning shelters for fish, shrimp, shellfish and other living things. Due to its effective result,artificial reef constructions have been wildely developed in the world. Shandong province, has initially built a large-scale construction of reefs along its coastline since 2000 in china,and so far,hundreds of large-scale artificial reefs have been completed, but how to value its effort in scientific perspective still does not form a systematic evaluating system.In this paper, the actual construction of artificial reefs in Shandong, by means of marine survey, a preliminary study has been made on the construction of five large artificial reefs'effect, at the same time, the scientific evaluation methods have been put up, key results are as follows:1. A mature development model on artificial reef construction has been formed in Japan, the United States and other countries. International artificial reef construction has been widely carried out, which accumulates rich experience to learn fromm.2.The ecological effects of artificial reefs is produced by changing the non-living environment around the area, which increased levels of nutrients and primary productivity. And its ecological effects are mainly embodied in the gathering fishery resources and the effect on enhancement.3.Great development has been achieved in artificial reef since "Fisheries Resource Restoration Project" has been implemented after 2005 in Shandong province. By the end of 2009,the government has supported 21 large-scaled artificial reefs for four times and has invested 244 million Yuan RMB cumulately in those projects, having built 1.118 million steres of artificial reefs with stone blocks and 603,000 steres with concrete structures. Meanwhile, the projects have also used 315 retired boats as artificial reefs. Through all those efforts,941 hectares artificial reefs with a total volume of 1796,500 m3 now have been available. Various materials have been utilized as reefs, such as stone blocks at the beginning, concrete structures, retired boats, FRP structures and discarded tyres in the recent years. As far as reef designment concerned, dozens of reefs of different configuration and different size are designed. Those artificial reefs have played an important role in improving the environment of the area, increasing the fishery landings. As a result, local people have gradually realized the importance of artificial reefs and are building reefs themselves. Up to now, about 100 artificial reefs have built or are being built in Shandong province, with an area of 50,000 ares. It is conservatively estimated that 500 million Yuan RMB have been invested in constructing artificial reefs.4. Evaluation of Artificial Reef Construction in Shandong Province.4.1 Rongcheng lidao artificial reef siteThe survey found that DO concentration is 1.4 times as before the reef being casted.The content of Zinc and cadmium were decreased.the total number of nekton,the diversity of species and the abundance of reef are 0.48 times,0.32times and 0.47 times higher than those before, respectively.The dominant species have not changed.Macrobenthic diversity and abundance of reef compared with casted before were 1.68 times and 1.62 times higher, respectively.CPUE is 0.4 times than the reef pre-casted.4.2 Rizhao qianshan island artificial reef siteThe survey found that DO concentration of reefs is 1.06 times higher than the pre-cast reef, The content of lead, zinc, chromium, arsenic was reduced, but copper, mercury levels increased,cadmium content changed little. the average content of chlorophyll a in reef area and the control zone is 1.1 and 1.0, respectively, the distribution is relative uniform. the ecological indices of zooplankton were higher than that of the control area, the composition of biological communities excelled the control area. Catch quantity, total weight and mean weight is 1.54 times,2.46 times and 1.18 times higher than that of the control area, respectively.Catch rates and Catch rate mantissa were 2.46 times and 1.54 times higher than that of the control area,respectively.4.3 Weihai xishan artificial reef siteThe survey found that major species of phytoplankton were more than the control area, and were easier to form dominant species. Benthic biomass and abundance in the reefs were rising over time, the average abundance of biomass and biological abundance is 2.28 times 1.43 times respectively as the control areas. The number of potnet fisheries, the total weight and average weight were separately 10 times,17.81 times and 1.99 times.as the control area. Catch rates and catch rate of mantissa were 7.39 times and 5.33 times in the control area,respectively.4.4 Shandong xunshan artificial reef siteThe survey found in the reef that lead, cadmium content decreased, while zinc, chromium, mercury content increased. The mean concentration ratio of chlorophyll a between reef area and the control were 1.8 and 1.6, respectively, indicating artificial reefs can increase the primary productivity. The average number of phytoplankton is lower compared with the control area.-The average density of zooplankton is 1.24 times as the control area. The average biomass of zooplankton and average weight were 1.24 times and 1.64 times as the control area.separately. The average reef benthic biomass was 53.60 times as the control area. Reef fish in cage number and total weight were 10.25 times and 4.9 times as the control area,respectively.4.5 Yantai Yangma island artificial reef siteThe survey found that the mean concentration chlorophyll a ratio between reef area and the control were 1.3 and 1.4, respectively. Important species in reef area and the number of types of common species are greater than the control area's, so is the species dominance. The average density of reef zooplanktonwas 1.33 timesas the control area, biomass and density were much larger than the control area's. Reef benthic species richness and species diversity index were higher than the control area's, the two types of Jaccard similarity index was 0.18, which showed little regional similarity between the two areas.According to the above-mentioned analysis, it can be seen that artificial reefs contribute to improving water quality, proliferate biological resources. After the artificial reefs were casted, the biomass and abundance of plankton and benthic increased, the biomass and biological abundance of reef was significantly higher than the control area's. The complex structure of Artificial reef and the new environment were formed after delivery, providing a variety of habitat areas used for biological spawning, feeding, nourishing.5. Prospects of artificial reefs in Shandong ProvinceThe directions of future development of artificial reefs in Shandong province include:First, in closed areas, promoting the styles of protecting artificial reef for the purpose of protecting the important fishery resources and fishing areas.Second, protecting artificial reef as important spawning grounds, migration channels should be carried out to protect spawning grounds and migrational routes.Third, proliferative artificial reef constructions should be carried out in coastal waters to maintain varieties of seafood.Fourth, It is necessary to conduct artificial reef construction in the desert ranch in order to improve the marine eco-system.