Effects Of The Different Maricultural Models On Sanggou Bay Ecosystem Services

Mariculture is one of main ways to use marine ecosystem. Sanggou Bay is a typical aquaculture bay in which the main human activity is aquaculture. There is only several short and local rivers flowing into the bay, industrial and living sewage into the bay is very less. The rapidly developed aquaculture had been produced highly intensitive pressure and significantly changed the structure and fuction of Sanggou Bay ecosystem, then changed the bay's ecosystem services to human. Aquaculture activity has different effects on the different marine ecosytem services. It has important scientific significance and practical needs to discover the long-term effects of aquaculture on marine ecosystem services.The effects of kelp and shellfish culture on the structure and function of Sanggou Bay ecosystem were analyzed and the changes of ecosystem services under the different aquacultural models in Sanggou Bay were discussed. By using the expert survey method, the changes in Sanggou Bay ecosysytem services due to kelp-shellfish polyculture were semi-quantitatively assessed. Aquaculture activities may improve the value of 12 ecosystem services i.e. food production, material production, scientific service, nutrient cycling, primary production, oxygen production, biological control, waste treatment, climate regulation, disturbance regulation, cultural value and recreational service. Aquaculture activites may reduce the value of 2 ecosystem services i.e. provision of genetic resources and species diversity maintenance.The total increment of ecosystem service value caused by large-scale kelp-shellfish polyculture activities was 556.43 million yuan. Food production service value increased 523.11 millin yuan, material production service value increased 2.09 million yuan, oxygen production service value increased 11.07 million yuan, climate regulation service value increased 14.54 million yuan, waste treatment service value increased 2.00 million yuan, scientific service value increased 3.62 million yuan. The main increment is from food production which accounts 94%. The kelp-shellfish polyculture is a friendly ecological mariculture model to use ecosystem service, it may totally improve most ecosystem services. However, kelp-shellfish polyculture is adverse to local biodiversity and genetic resources of native species. Therefore, the habitat of wild species, the migratory and spawning sites should be avoided.