Ballast Water Risk Assessment Model Based On Ecological Similarity

With China's accession to WTO, China has been communicating with other countries more frequently, and also economic has developed more rapidly. Alien species enter the country through trade, tourism, transport and other means, a lot of which have caused the invasion. The invasive species not only cause huge economic losses, but also damage the environment seriously. The invasion of aquatic ecosystem is the most serious situation. Ballast water is the main invasion way of alien aquatic organisms. The complex effects caused by the aquatic organisms via ballast water have attracted world wide attention. With this regard, the paper used risk assessment to prevent the invasion of alien aquatic organisms.Based on the research of the invasion by alien marine species, the paper analyzed the factors which can impact the invasion of alien aquatic organisms in detail. Refer to the "international convention of ship ballast water and sediment control and management" the A-4 provided guidelines for risk assessment within the (G7), Globallast project and the initial model of our group, the new model has changed the factors. And it has used different weight to analysis the factors. The paper optimized the risk factors, constructed new weight and modified each risk factor, calculated value at risk and finally established the risk degree of source ports for destination ports. The paper developed a new system following the correction and perfect model, to promote the application of this model for further time. Main tasks are as follows:First, this model contains community structure similarity, environmental similarity, risk species factor, maximum tank volume factor and minimum storage time factor. This ballast water risk assessment model is established by hierarchical analysis and fuzzy statistical thinking.Second, the paper has selected Odessa Port and Dalian Port as the destination port to verify the model and the results compared to the globllast project, ultimately the results are reasonable. That indicates that the new model by optimization is practical.Third, the paper has used Visual Basic language, combined with Access database to development the system. The system is divided into three modules:query/additional port information modules, add/query access information module, port risk factor check and edit the content. The risk assessment model system can provide information, such as, query, add and display.After the model validation, the new model is feasible and practical, which can develop a system. The developed system will be submitted to the Marine Management Department eventually, to assist in ship's ballast water management, which can control the emission of the ship's ballast water which carried alien aquatic organisms. So that it can reduce the invasion risk of alien aquatic organisms and avoid the damage by the invasion.