The Fourth International Stock Enhancement & Searanching

Theme A: The role of releases of cultured animals in fisheries management and ecosystem restoration:  integrative evaluation

5. EVALUATING ECOSYSTEM STRUCTURE AND PREDICTING THE ECOLOGICAL CARRYING CAPACITY FOR Stichopus japonicus AND Haliotis discus hanna iOF LIDAO ARTIFICAL REEF ZONE IN SHANDONG PROVINCE


Zhongxin Wu, Xiumei Zhang
College of Fisheries, Ocean University of China
wuzhongxin2007@126.com

Based on the environmental and biological data obtained from monthly surveys in Lidao artifical reef zone during 2009, a balanced trophic model of Lidao artifical reef ecosystem was constructed by using the Ecopath with Ecosim software package. The model consisted of 19 functional groups which covered the main trophic flow in Lidao artifical reef ecosystem. Trophic flow and ecological carrying capacity of the artifical reef system were analyzed and predicted. The results showed that the trophic level of the function groups varied from 1.0~3.921. The geometric mean of the trophic transfer efficiencies was 9.9%, with 10.3% from detritus and 9.7% from primary producers within the system. In the course of the trophic flow, the proportion of total flow originating from detritus was 39%, and from primary producer was 61%. Four ecosystem attributes including TPP/TR(total primary production/ total respiration), CI(connectivity index), FCI(Finn’s cycling index) and MPL(mean path length) were 2.688, 0.321, 2.20 and 2.357 respectively, indicating that the system is approaching the mature stage according to Odum’s theory. The ecological enviroment and the output of fisheries in artifcial reef zone will be gradually steady. Moreover, we predicted the ecological carrying capacity for sea cucumber(Stichopus japonicus) and abalone(Haliotis discus hannai), which are the main enhancemental species in the system. The ecological carrying capacity was defined as the level of enhancement that could be introduced without significantly changing the major trophic fluxes or structure of the food web. The ecological carrying capacities for sea cucumber and abalone were found to be 309 t km-2 year-1 and 198.86 t km-2 year-1 in Lidao artifical reef zone, respectively.