| The Bohai Sea is an unique semi-closed marginal sea in China, which contains the Laizhou Bay, the Bohai Bay and the Liaodong Bay. Marine ecosystems in the Bohai Sea has been vulnerable recently due to its poor capacity of water exchanging, the increasing discharge of anthropogenic pollutants and the local marine resources recession. Eventually, the ecological service function and sustainable utilization function of Bohai Sea would disappear in case of neglectance. The Penglai 19-3 oil spill puts serious damages to the ecological environment in the Bohai sea. Meanwhile, attention has been focused on the ecological environment in the Laizhou Bay as well. The purpose of this thesis is to provide the reference and support for the protection of ecological environment and reasonable utilization of fishery resources in the Bohai Sea, by estimating the economic damages from the Penglai 19-3 oil spill to the Yantai fisheries and evaluating the community structure characteristics of fish eggs and larvae in the Laizhou Bay.The method of comparative analysis and the analytic hierarchy process(AHP) were applied in this thesis. The research has focused on fishery economy before and after the Penglai 19-3 oil spill happened in 2011 and utilized survey results of fish eggs and larvae and marine water samples in Laizhou Bay, 2014. The main results were as follows:1?Estimating the economic damages from the Penglai 19-3 oil spill to the Yantai fishery.The economic damages from the Penglai 19-3 oil spill through statistical processing of fishery economic before and after the Penglai 19-3 oil spill happened in 2011 were estimated. The results showed that the total economic loss was up to 1.256 Billion RMB which consisted the following two economic sectors: the Yantai mari-aquaculture and the Yantai releasing fishery. The oil spill accident leaded to a severe impact on the mari-aquaculture. The economic loss was mainly from a reduction of production in crustacean, shellfish, algae, sea cucumber and sea urchin, up to 1239.5 Million RMB. In the aspect of the stock releasing fishery, the total economic loss due to the oil pollution for the stock releasing fishery were up to 16.85 Million RMB. Among them, there was a sharp fall of production for Rhopilema ecculentum.2?The survey of fish eggs and larvae and marine water samples in the Laizhou BayThe community structure of fish eggs and larvae and water samples in Laizhou Bay in 2014 were investigated in this study. Results showed that Engraulis japonicus was the important species of the fish communities in the Laizhou Bay in 2014, which was the dominant species of fish eggs in May and their larvae in June. The average levels of ammonium nitrogen, arsenic and antimony of the seawater in May were less than those were in September. The areas with high level of these substances were in the coastal areas where a great amount of runoffs went into the Laizhou Bay.3?Assessing the community structure characteristics of fish eggs and larvae in Laizhou Bay by AHPThe community structure characteristics of fish eggs and larvae were evaluated by AHP. There were 19 sample stations in the Laizhou Bay in May, June and September, 2014. The hierarchy analysis model composed of three kinds of index which were biological index, economic index and chemical index, respectively. The relative importance of each index was obtained through questionnaires and the index weights were calculated by the software. Lots of sentitivity analysis to the hierarchy analysis model were conducted. Results demonstrated that the distribution of optimal region showed an obvious trend of the movement from inshore area to central area in Laizhou Bay on the time series from May to September. |
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