Food web structure prior to and following construction of artificial reefs, based on stable isotope analysis

The food web structure prior to and following the construction of artificial reefs (ARs) in the sea area around Xiaoheishan Island was established and a comparative study was conducted using stable isotopes. A total of 49 common marine animal samples were collected and used to construct the food web. Four types of food sources were detected in this area. Following construction of the reefs, the total contribution rates of Ulva pertusa and particulate organic matter decreased by 1.4% and 1%, respectively, whereas Zostera marina/Sargassum thunbergii and sediment increased by 1.5% and 0.6%, respectively. Within two years following construction, most of the omnivorous and carnivorous consumers were getting more focused. The average contribution rates of food sources of seven species changed by greater than 10%. Within two years following construction, most of the fish trophic levels decreased and most of the invertebrate trophic levels increased.