26 MARCH 2015 • WORLD AQUACULTURE • WWW.WAS.ORG Types of Integrated Multi-Trophic Aquaculture Practiced in China Jianguang Fang and Jihong Zhang China is the largest mariculture producer in the world, both in terms of volume and total value. In 2010 the mariculture production of the Chinese mainland was 23.6 million t (Table 1), contributing to nearly 65 percent of global production of cultured aquatic products. Currently aquaculture in China encounters challenges such as environmental deterioration and eutrophication caused by fed mariculture. Although the growth of mariculture in China continues to be high, the sustainability of its development has drawn critical attention. The mariculture industry worldwide is searching for sustainable methods and integrated multitrophic aquaculture (IMTA) has been proposed as a potential solution (Troell et al. 2003, Neori et al. 2004, Soto 2009). Two types of IMTA are practiced in northern China. One type is sea ranching or sea bottom culture in the subtidal zone of Zhangzidao Island and Sungo Bay (also known as Sanggou Bay), China, which includes the following combinations: seaweed + sea urchin + sea cucumber, sea cucumber + scallop, seaweed + abalone, eelgrass + sea cucumber + clam. Another type is IMTA practiced for suspended mariculture in Sungo Bay, China. This article describes these two types of IMTA as they are practiced in China. IMTA for Sea Ranching in the Subtidal Zone Zhangzidao Island. IMTA for sea ranching has been implemented by the Zhang Zi Dao Fishery Group Company adjacent to Zhangzidao Island. In this IMTA system (Table 2), seaweed and scallops are produced from natural recruitment. Seaweed is used as food for abalone and sea urchins, while benthic seaweed in the system has the function of providing shelter for swimming animals and benthic organisms. Seaweed plays an important role in nutrient cycling. In this system, the faeces of scallop and abalone and natural organic sediment are used as food by sea cucumbers. Ammonia excreted by fed animals is absorbed by phytoplankton and seaweed. Phytoplankton is used as the food base of scallops and seaweed and phytoplankton provide dissolved oxygen to the animals. Sungo Bay. IMTA experiments of sea-ranching abalone and sea cucumber were carried out in the area managed by the Chudao Island Company, located at the south cape of Sungo Bay. In this area, seaweed is used as food for abalone and sea urchin, while sea grass in the system has the function of providing shelter for swimming animals and benthic organisms and for nutrient cycling. In this system, the faeces of clam and abalone and natural organic sediment are used as food by the sea cucumber. Ammonia excreted by fed animals is absorbed by phytoplankton and seaweed. Phytoplankton is used by clams and seaweed and phytoplankton provide oxygen to the animals. The enhancement of abalone Haliotis discus hannai, sea TABLE 1. The annual marine aquaculture production (t) in China and the proportion of global marine aquaculture production from China in 2010 (FAO 2012). Total Shellfish Seaweeds (wet weight) World 36,704,512 13,843,761 18,384,434 China 23,625,465 11,082,973 10,995,210 China/World 64.4% 80.1% 59.8%
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