Ecological Effects And The Ecosystem Services Of Artificial Oyster Shell Reef

Marine ranching is a good method to restore offshore damaged marine ecosystem, protect marine environment and foster the marine fishery resources. The deployment of artificial reef is the main part of marine ranching construction. Artificial reef defines as a group of activities that aim to remodel the marine ecosystem by offering new habitats. Artificial reef has the impacts on adjoining environment and biotic community. Sea cucumber Apostichopus japonicus Selenka became the main marine culture species in the northern China coast. The shallow water culture is the main culture type. The artificial oyster shell reef has been used in Shandong and Liaoning province. The reef can provide convenient habitat and food to sea cucumber. The reef has obvious economic effects. We studied the ecological effects and investigated the ecosystem services of the artificial oyster shell reef in Rongcheng Bay eastern in Shandong Peninsula. The main results are as follows.The small Crustacean were the most abundant species on the artificial oyster shell reef, while the Echnidomata was the most in density because the biomass of sea cucumber was high. There was no sessile organism in the reef. The difference between the macrobenthos in reef and nearby sediment area were significant. The species most contributed to the dissimilarity between the two area were Crustacean. According to the stable isotope, the fauna in the artificial reef area can be divided into3trophic levels and5ecological function groups. The primary consumer feeding on the particle organic matter and sediment, the primary consumer feeding on detritus, the second consumer feeding on detritus and primary consumer, and the second consumer feeding on the primary consumer were the main four function groups. Sea cucumber A. japonicus was on the second trophic level, feeding on the sediment and detritus. Hexagrammos otakii and Sebastes schlegeli were on the third trophic level, but those two species has different feeding preferences. The feeding of the former was more complex and the latter was more carnivorous.The sediment environment and the abundance and biomass of macrobenths in reef and non-reef area were not significantly different. The ANOSIM test based on the every bimestrial data revealed that the artificial reef of oyster shell may change the macrobenthic community significantly in some months. The PERMANOVA test based on all sampling data showed that the time factor had significant effects on macrobenthos communities. The small polychaete, crustacean, and mollusk were most contribution species for multivariate dissimilarity between the two areas. The artificial oyster shell reef may slightly improve the environmental quality indicated by the ecological indicators based on the macrobenthos in winter. The DistLM and multi-model inference approach revealed that the ch1-a and TN were the important predictors in the reef area while TOM and ch1-a were in non-reef area.The highest temperature in the oyster shell reef through the year was23℃in September, while the lowest was2℃in February. The settling particulate matter sediment in spring was high and was low in summer and winter. According to the physiochemical characteristics, the organic matter of natural deposited sediment and sediment, the carrying capacity for the ranching of sea cucumber in the artificial oyster shell reef was212g m-2a-1.The middle size (15g/ind.-20g/ind.) of sea cucumber was fitted to culture in the artificial oyster shell reef. The maximum stocking biomass for sea cucumber cultured in the artificial oyster shell reef was793g/m.The ecosystem service value per unit area of the artificial oyster shell reef was estimated at￥12,910,000km-2a-1. The direct service value was93,89,000km-2a-1and the indirect service value was3,517,000km-2a-1. The high value of ecosystem service in this area may because the studied area was Integrated Multi-Trophic Aquaculture model. The kelp was cultured in the upper water and the sea cucumber was on the reef, while the fish was in the middle. The add ecosystem service value after deploying the artificial oyster shell reef was estimated at￥1,937,300km-2a-1. The main service was the climate regulating services as the oyster fixed more carbon. The second service was the foodprovision services because of the culture of sea cucumber on the reef.The fauna in the artificial reef area can be divided into3trophic levels and5ecological function groups. The artificial oyster shell reef can use natural deposit andprovide suitable habitat for sea cucumber and other fishery resources. The artificial reefhad significant effects to the benthic ecosystem in winter. The artificial oyster shell reefprovided seafood，controlled water quality, had effects of Carbon sequestration, and sothe reef had high ecosystem services. Enhancement of oyster shell reef studies are neededand this kind of artificial reef is needed to be optimized，prompted and implemented inmore area in the next step.