Abstract:In this study, we used a fuzzy synthetic evaluation to build an ecosystem-health assessment model according to offshore sea ecosystem characteristics and artificial reef construction functions from three aspects: Physicochemical environment, biological community structure and ecosystem function. To eliminate the dimension effect of sub-indexes, normalization process was used. An analytic hierarchy process was used to assign a threshold or the ecological indicator. The synthetic health index was used to assess the health status of the artificial reef areas, radiation areas and contrast areas. Sub-indexes of artificial reef ecosystem health assessments included physical, chemical, and biological factors. Assessment standards were based on seawater quality, standard marine sediment quality, and guidance for the assessment of coastal marine ecosystem health. We conducted a series of ecosystem health assessments of artificial reefs, and radiation and control areas of Danglang Island based on the survey results of 5 voyages in 2013~2015. The results showed that the ecosystem of artificial reef areas was in a healthy state, whereas the control area was in a sub-healthy state. From the highest to the lowest, the ecological health index was: The three reef area (0.783)>radiation areas (0.646)>control area (0.594). Compared with non-reefing, the ecosystems of the reef and radiant areas were all separated from the sub-healthy state and gradually improved, however, the control area was still in a sub-healthy state and its development was unstable. Therefore, the conclusion was that the ecosystem of the artificial reef areas of Danglang Island were more stable than the control areas, and ecosystem health of radiation areas, was gotten better, due to effect of reefs. The study of reef ecosystem health and scientifically assessing artificial reef ecological effects is important for the construction of reef projects, environment protection, stock enhancement, efficient administration, and sustainable development of fisheries.
