Energy flow analysis of in Litopenaeus vannamei-Tegillarca granosa polyculture ponds based on EwE model

Abstract

In order to characterize the energy flow and trophic structure of a polyculture pond that contained Litopenaeus vannamei and Tegillarca granosa, we used an Ecopath with Ecosim (EwE) model. We constructed the EwE model using 13 functional groups including L. vannamei, T. granosa, macrozooplankton, microzooplankton, microbenthos, bacterioplankton, benthic bacteria, micro-phytoplankton, nano-phytoplankton, pico-phytoplankton, artificial feed, detritus in water, and detritus in sediment. Our findings showed that this polyculture ecosystem contained five trophic levels and that two of them accounted for 99.41% of the total system throughput. L. vannamei, microbenthos, and detritus in sediment displayed high ecotrophic efficiency (EE) values, while artificial feed held relatively low EE implying that the artificial feed was used inefficiently. The bacteria including benthic bacteria and bacterioplankton was inefficiently used. The main energy flows were associated with artificial feed, phytoplankton, and detritus in this polyculture system. The compatibility of L. vannamei and T. granosa was high according to the mixed trophic impact analysis. In conclusion, the study showed that this polyculture ecosystem still needed to be improved in the aspects of energy consumption. It would be necessary for this polyculture ecosystem to perform further optimization and enhancement on the energy utilization efficiency and comprehensive benefits.

Keywords

• Litopenaeus vannamei
• Tegillarca granosa
• Trophic structure
• Energy flow
• Ecopath with Ecosim